- Thank you very much for the opportunity to speak carbon dioxide angiography, which is one of my favorite topics and today I will like to talk to you about the value of CO2 angiography for abdominal and pelvic trauma and why and how to use carbon dioxide angiography with massive bleeding and when to supplement CO2 with iodinated contrast.
Disclosures, none. The value of CO2 angiography, what are the advantages perhaps? Carbon dioxide is non-allergic and non-nephrotoxic contrast agent, meaning CO2 is the only proven safe contrast in patients with a contrast allergy and the renal failure.
Carbon dioxide is very highly soluble (20 to 30 times more soluble than oxygen). It's very low viscosity, which is a very unique physical property that you can take advantage of it in doing angiography and CO2 is 1/400 iodinated contrast in viscosity.
Because of low viscosity, now we can use smaller catheter, like a micro-catheter, coaxially to the angiogram using end hole catheter. You do not need five hole catheter such as Pigtail. Also, because of low viscosity, you can detect bleeding much more efficiently.
It demonstrates to the aneurysm and arteriovenous fistula. The other interesting part of the CO2 when you inject in the vessel the CO2 basically refluxes back so you can see the more central vessel. In other words, when you inject contrast, you see only forward vessel, whereas when you inject CO2,
you do a pass with not only peripheral vessels and also see more central vessels. So basically you see the vessels around the lesions and you can use unlimited volumes of CO2 if you separate two to three minutes because CO2 is exhaled by the respirations
so basically you can inject large volumes particularly when you have long prolonged procedures, and most importantly, CO2 is very inexpensive. Where there are basically two methods that will deliver CO2. One is the plastic bag system which you basically fill up with a CO2 tank three times and then empty three times
and keep the fourth time and then you connect to the delivery system and basically closest inject for DSA. The other devices, the CO2mmander with the angio assist, which I saw in the booth outside. That's FDA approved for CO2 injections and is very convenient to use.
It's called CO2mmander. So, most of the CO2 angios can be done with end hole catheter. So basically you eliminate the need for pigtail. You can use any of these cobra catheters, shepherd hook and the Simmons.
If you look at this image in the Levitor study with vascular model, when you inject end hole catheter when the CO2 exits from the tip of catheter, it forms very homogenous bolus, displaces the blood because you're imaging the blood vessel by displacing blood with contrast is mixed with blood, therefore as CO2
travels distally it maintains the CO2 density whereas contrast dilutes and lose the densities. So we recommend end hole catheter. So that means you can do an arteriogram with end hole catheter and then do a select arteriogram. You don't need to replace the pigtail
for selective injection following your aortographies. Here's the basic techniques: Now when you do CO2 angiogram, trauma patient, abdominal/pelvic traumas, start with CO2 aortography. You'll be surprised, you'll see many of those bleeding on aortogram, and also you can repeat, if necessary,
with CO2 at the multiple different levels like, celiac, renal, or aortic bifurcation but be sure to inject below diaphragm. Do not go above diaphragm, for example, thoracic aorta coronary, and brachial, and the subclavian if you inject CO2, you'll have some serious problems.
So stay below the diaphragm as an arterial contrast. Selective injection iodinated contrast for a road map. We like to do super selective arteriogram for embolization et cetera. Then use a contrast to get anomalies. Super selective injection with iodinated contrast
before embolization if there's no bleeding then repeat with CO2 because of low viscocity and also explosion of the gas you will often see the bleeding. That makes it more comfortable before embolization. Here is a splenic trauma patient.
CO2 is injected into the aorta at the level of the celiac access. Now you see the extra vascularization from the low polar spleen, then you catheterize celiac access of the veins. You microcatheter in the distal splenic arteries
and inject the contrast. Oops, there's no bleeding. Make you very uncomfortable for embolizations. We always like to see the actual vascularization before place particle or coils. At that time you can inject CO2 and you can see
actual vascularization and make you more comfortable before embolization. You can inject CO2, the selective injection like in here in a patient with the splenic trauma. The celiac injection of CO2 shows the growth, laceration splenic with extra vascularization with the gas.
There's multiple small, little collection. We call this Starry Night by Van Gogh. That means malpighian marginal sinus with stagnation with the CO2 gives multiple globular appearance of the stars called Starry Night.
You can see the early filling of the portal vein because of disruption of the intrasplenic microvascular structures. Now you see the splenic vein. Normally, you shouldn't see splenic vein while following CO2 injections.
This is a case of the liver traumas. Because the liver is a little more anterior the celiac that is coming off of the anterior aspect of the aorta, therefore, CO2 likes to go there because of buoyancy so we take advantage of buoyancy. Now you see the rupture here in this liver
with following the aortic injections then you inject contrast in the celiac axis to get road map so you can travel through this torus anatomy for embolizations for the road map for with contrast. This patient with elaston loss
with ruptured venal arteries, massive bleeding from many renal rupture with retro peritoneal bleeding with CO2 and aortic injection and then you inject contrast into renal artery and coil embolization but I think the stent is very dangerous in a patient with elaston loss.
We want to really separate the renal artery. Then you're basically at the mercy of the bleeding. So we like a very soft coil but basically coil the entire renal arteries. That was done. - Thank you very much.
- Time is over already? - Yeah. - Oh, OK. Let's finish up. Arteriogram and we inject CO2 contrast twice. Here's the final conclusions.
CO2 is a valuable imaging modality for abdominal and pelvic trauma. Start with CO2 aortography, if indicated. Repeat injections at multiple levels below diaphragm and selective injection road map with contrast. The last advice fo
t air contamination during the CO2 angiograms. Thank you.
- I want to thank the organizers for putting together such an excellent symposium. This is quite unique in our field. So the number of dialysis patients in the US is on the order of 700 thousand as of 2015, which is the last USRDS that's available. The reality is that adrenal disease is increasing worldwide
and the need for access is increasing. Of course fistula first is an important portion of what we do for these patients. But the reality is 80 to 90% of these patients end up starting with a tunneled dialysis catheter. While placement of a tunneled dialysis catheter
is considered fairly routine, it's also clearly associated with a small chance of mechanical complications on the order of 1% at least with bleeding or hema pneumothorax. And when we've looked through the literature, we can notice that these issues
that have been looked at have been, the literature is somewhat old. It seemed to be at variance of what our clinical practice was. So we decided, let's go look back at our data. Inpatients who underwent placement
of a tunneled dialysis catheter between 1998 and 2017 reviewed all their catheters. These are all inpatients. We have a 2,220 Tesio catheter places, in 1,400 different patients. 93% of them placed on the right side
and all the catheters were placed with ultrasound guidance for the puncture. Now the puncture in general was performed with an 18 gauge needle. However, if we notice that the vein was somewhat collapsing with respiratory variation,
then we would use a routinely use a micropuncture set. All of the patients after the procedures had chest x-ray performed at the end of the procedure. Just to document that everything was okay. The patients had the classic risk factors that you'd expect. They're old, diabetes, hypertension,
coronary artery disease, et cetera. In this consecutive series, we had no case of post operative hemo or pneumothorax. We had two cut downs, however, for arterial bleeding from branches of the external carotid artery that we couldn't see very well,
and when we took out the dilator, patient started to bleed. We had three patients in the series that had to have a subsequent revision of the catheter due to mal positioning of the catheter. We suggest that using modern day techniques
with ultrasound guidance that you can minimize your incidents of mechanical complications for tunnel dialysis catheter placement. We also suggest that other centers need to confirm this data using ultrasound guidance as a routine portion of the cannulation
of the internal jugular veins. The KDOQI guidelines actually do suggest the routine use of duplex ultrasonography for placement of tunnel dialysis catheters, but this really hasn't been incorporated in much of the literature outside of KDOQI.
We would suggest that it may actually be something that may be worth putting into the surgical critical care literature also. Now having said that, not everything was all roses. We did have some cases where things didn't go
so straight forward. We want to drill down a little bit into this also. We had 35 patients when we put, after we cannulated the vein, we can see that it was patent. If it wasn't we'd go to the other side
or do something else. But in 35%, 35 patients, we can put the needle into the vein and get good flashback but the wire won't go down into the central circulation.
Those patients, we would routinely do a venogram, we would try to cross the lesion if we saw a lesion. If it was a chronically occluded vein, and we weren't able to cross it, we would just go to another site. Those venograms, however, gave us some information.
On occasion, the vein which is torturous for some reason or another, we did a venogram, it was torturous. We rolled across the vein and completed the procedure. In six of the patients, the veins were chronically occluded
and we had to go someplace else. In 20 patients, however, they had prior cannulation in the central vein at some time, remote. There was a severe stenosis of the intrathoracic veins. In 19 of those cases, we were able to cross the lesion in the central veins.
Do a balloon angioplasty with an 8 millimeter balloon and then place the catheter. One additional case, however, do the balloon angioplasty but we were still not able to place the catheter and we had to go to another site.
Seven of these lesions underwent balloon angioplasty of the innominate vein. 11 of them were in the proximal internal jugular vein, and two of them were in the superior vena cava. We had no subsequent severe swelling of the neck, arm, or face,
despite having a stenotic vein that we just put a catheter into, and no subsequent DVT on duplexes that were obtained after these procedures. Based on these data, we suggest that venous balloon angioplasty can be used in these patients
to maintain the site of an access, even with the stenotic vein that if your wire doesn't go down on the first pass, don't abandon the vein, shoot a little dye, see what the problem is,
and you may be able to use that vein still and maintain the other arm for AV access or fistular graft or whatever they need. Based upon these data, we feel that using ultrasound guidance should be a routine portion of these procedures,
and venoplasty should be performed when the wire is not passing for a central vein problem. Thank you.
- These are my disclosures. So central venous access is frequently employed throughout the world for a variety of purposes. These catheters range anywhere between seven and 11 French sheaths. And it's recognized, even in the best case scenario, that there are iatrogenic arterial injuries
that can occur, ranging between three to 5%. And even a smaller proportion of patients will present after complications from access with either a pseudoaneurysm, fistula formation, dissection, or distal embolization. In thinking about these, as you see these as consultations
on your service, our thoughts are to think about it in four primary things. Number one is the anatomic location, and I think imaging is very helpful. This is a vas cath in the carotid artery. The second is th
how long the device has been dwelling in the carotid or the subclavian circulation. Assessment for thrombus around the catheter, and then obviously the size of the hole and the size of the catheter.
Several years ago we undertook a retrospective review and looked at this, and we looked at all carotid, subclavian, and innominate iatrogenic injuries, and we excluded all the injuries that were treated, that were manifest early and treated with just manual compression.
It's a small cohort of patients, we had 12 cases. Eight were treated with a variety of endovascular techniques and four were treated with open surgery. So, to illustrate our approach, I thought what I would do is just show you four cases on how we treated some of these types of problems.
The first one is a 75 year-old gentleman who's three days status post a coronary bypass graft with a LIMA graft to his LAD. He had a cordis catheter in his chest on the left side, which was discovered to be in the left subclavian artery as opposed to the vein.
So this nine French sheath, this is the imaging showing where the entry site is, just underneath the clavicle. You can see the vertebral and the IMA are both patent. And this is an angiogram from a catheter with which was placed in the femoral artery at the time that we were going to take care of this
with a four French catheter. For this case, we had duel access, so we had access from the groin with a sheath and a wire in place in case we needed to treat this from below. Then from above, we rewired the cordis catheter,
placed a suture-mediated closure device, sutured it down, left the wire in place, and shot this angiogram, which you can see very clearly has now taken care of the bleeding site. There's some pinching here after the wire was removed,
this abated without any difficulty. Second case is a 26 year-old woman with a diagnosis of vascular EDS. She presented to the operating room for a small bowel obstruction. Anesthesia has tried to attempt to put a central venous
catheter access in there. There unfortunately was an injury to the right subclavian vein. After she recovered from her operation, on cross sectional imaging you can see that she has this large pseudoaneurysm
coming from the subclavian artery on this axial cut and also on the sagittal view. Because she's a vascular EDS patient, we did this open brachial approach. We placed a stent graft across the area of injury to exclude the aneurism.
And you can see that there's still some filling in this region here. And it appeared to be coming from the internal mammary artery. We gave her a few days, it still was patent. Cross-sectional imaging confirmed this,
and so this was eventually treated with thoracoscopic clipping and resolved flow into the aneurism. The next case is a little bit more complicated. This is an 80 year-old woman with polycythemia vera who had a plasmapheresis catheter,
nine French sheath placed on the left subclavian artery which was diagnosed five days post procedure when she presented with a posterior circulation stroke. As you can see on the imaging, her vertebral's open, her mammary's open, she has this catheter in the significant clot
in this region. To manage this, again, we did duel access. So right femoral approach, left brachial approach. We placed the filter element in the vertebral artery. Balloon occlusion of the subclavian, and then a stent graft coverage of the area
and took the plasmapheresis catheter out and then suction embolectomy. And then the last case is a 47 year-old woman who had an attempted right subclavian vein access and it was known that she had a pulsatile mass in the supraclavicular fossa.
Was noted to have a 3cm subclavian artery pseudoaneurysm. Very broad base, short neck, and we elected to treat this with open surgical technique. So I think as you see these consults, the things to factor in to your management decision are: number one, the location.
Number two, the complication of whether it's thrombus, pseudoaneurysm, or fistula. It's very important to identify whether there is pericatheter thrombus. There's a variety of techniques available for treatment, ranging from manual compression,
endovascular techniques, and open repair. I think the primary point here is the prevention with ultrasound guidance is very important when placing these catheters. Thank you. (clapping)
- Talk to you a little bit about again a major paradigm shift in AVMs which is the retrograde vein approach. I mean I think the biggest benefit and the biggest change that we've seen has been in the Yakes classification the acknowledgment
and understanding that the safety, efficacy and cure rate for AVMs is essentially 100% in certain types of lesions where the transvenous approach is not only safer, but easier and far more effective. So, it's the Yakes classification
and we're talking about a variety of lesions including Yakes one, coils and plugs. Two A the classic nidus. Three B single outflow vein. And we're talking now about these type of lesions. Three A aneurysmal vein single outflow.
Three B multiple outflows and diffuse. This is what I personally refer to as venous predominant lesions. And it's these lesions which I think have yielded the most gratifying and most dramatic results. Close to 100% cure if done properly
and that's the Yakes classification and that's really what it's given us to a great degree. So, Yakes one has been talked about, not a problem put a plus in it it's just an artery to vein.
We all know how to do that. That's pulmonary AVM or other things. Yakes two B however, is a nidus is still present but there is a single outflow aneurysmal vein. And there are two endovascular approaches. Direct puncture, transarterial,
but transvenous retrograde or direct puncture of the vein aneurism with the coil, right. You got to get to the vein, and the way to get to the vein is either by directly puncturing which is increasingly used, but occasionally transvenous. So, here's an example I showed a similar one before,
as I said I think some of these are post phlebitic but they represent the archetype of this type of lesion a two B where coil embolization results in cure, durable usually one step sometimes a little more. In the old days we used to do multiple
arterial injections, we now know that that's not necessary. This is this case I showed earlier. I think the thing I want to show here is the nature of the arteriovenous connection. Notice the nidus there just on this side of the
vein wall with a single venous outflow, and this can of course be cured by puncture, there's the needle coming in. And interestingly these needles can be placed in any way. Wayne and I have talked about this.
I've gone through the bladder under ultrasound guidance, I've gone from behind and whatever access you can get that's safe, as long as you can get a needle into it an 18 gauge needle, blow coils in you get a little tired, and you're there a long time putting in
coils and guide wires and so on. But the cures are miraculous, nothing short of miraculous. And many of these patients are patients who have been treated inappropriately in the past and have had very poor outcomes,
and they can be cured. And that a three year follow-up. The transcatheter retrograde vein is occasionally available. Here's an example of an acquired but still an AVM an acquired AVM
of the uterus where you see the venous filling on the left, lots of arteries. This cannot be treated with the arterial approach folks. So, this one happened to be available
and I was having fun with it as well, which is through the contralateral vein in and I was able to catheterize that coil embolization, cured so. Three A is a slightly different variant but it's important it is different.
Multiple in-flow arteries into an aneurysmal vein wall. And the important identification Wayne has given us is that the vein wall itself is the nidus and there's a single out-flow vein. So, once again, attacking the vein wall by destroying the vein, packing
and thrombosing that nidus. I think it's a combination of compression and thrombosis can often be curative. A few examples of that this was shown earlier, this is from Dr. Yake's experience but it's a beautiful example
and we try to give you the best examples of a singular type of lesion so you understand the anatomy. That's the sequential and now you see single out-flow vein. How do you treat this?
Coil embolization, direct puncture and ultimately a cure. And that's the arteriogram. Cured. And I think it's a several year follow-up two or three year follow-up on this one.
So a simple lesion, but illustrative of what we're trying to do here. A foot AVM with a single out-flow vein, this is cured by a combination of direct puncture right at the vein. And you know I would say that the beauty of
venous approach is actually something which it isn't widely acknowledged, which is the safety element. Let's say you're wrong, let's say you're treating an AVM and you think okay I'm going to attack
from the vein side, well, if you're not successful from the vein side, you've lost nothing. The risk in all of these folks is, if you're in the artery and you don't understand that the artery is feeding significant tissue,
these are where all the catastrophic, disastrous complications you've heard so much about have occurred. It's because the individuals do not understand that they're in a nutrient artery. So, when in doubt direct puncture
and stay on the venous side. You can't hurt yourself with ethanol and that's why ethanol is as safe as it is when it's used properly. So, three B finally is multiple in-flow arteries/arterioles shunting into an aneurysmal vein
this is multiple out-flow veins. So direct puncture, coils into multiple veins multiple sessions. So, here's an example of that. This is with alcohol this is a gentleman I saw with a bad ulcer,
and this looks impossible correct? But look at the left hand arteriogram, you can see the filling of veins. Look at the right hand in a slight oblique. The answer here is to puncture that vein. Where do we have our coil.
The answer is to puncture here, and this is thin tissue, but we're injecting there. See we're right at the vein, right here and this is a combination arteriogram. Artery first, injection into the vein.
Now we're at the (mumbles), alcohol is repeatedly placed into this, and you can see that we're actually filling the nidus here. See here. There's sclerosis beginning destruction of the vein
with allowing the alcohol to go into the nidus and we see progressive healing and ultimately resolution of the ulcer. So, a very complex lesion which seemingly looks impossible is cured by alcohol in an out-flow vein.
So the Yakes classification of AVMs is the only one in which architecture inform treatment and produces consistent cures. And venous predominant lesions, as I've shown you here, are now curable in a high percentage of cases
when the underlying anatomy is understood and the proper techniques are chosen. Thanks very much.
- Good morning. I'd like to thank Dr. Veith and Symposium for my opportunity to speak. I have no disclosures. So the in Endovascular Surgery, there is decrease open surgical bypass. But, bypass is still required for many patients with PAD.
Autologous vein is preferred for increase patency lower infection rate. And, Traditional Open Vein Harvest does require lengthy incisions. In 1996 cardiac surgery reported Endoscopic Vein Harvest. So the early prospective randomized trial
in the cardiac literature, did report wound complications from Open Vein Harvest to be as high as 19-20%, and decreased down to 4% with Endoscopic Vein Harvest. Lopes et al, initially, reported increase risk of 12-18 month graft failure and increased three year mortality.
But, there were many small studies that show no effect on patency and decreased wound complications. So, in 2005, Endoscopic Vein Harvest was recommended as standard of care in cardiac surgical patients. So what about our field? The advantages of Open Vein Harvest,
we all know how to do it. There's no learning curve. It's performed under direct visualization. Side branches are ligated with suture and divided sharply. Long term patency of the bypass is established. Disadvantages of the Open Vein Harvest,
large wound or many skip wounds has an increased morbidity. PAD patients have an increased risk for wound complications compared to the cardiac patients as high as 22-44%. The poor healing can be due to ischemia, diabetes, renal failure, and other comorbid conditions.
These can include hematoma, dehiscense, infection, and increased length of stay. So the advantages of Endoscopic Vein Harvest, is that there's no long incisions, they can be performed via one or two small incisions. Limiting the size of an incision
decreases wound complications. It's the standard of care in cardiac surgery, and there's an overall lower morbidity. The disadvantages of is that there's a learning curve. Electro-cautery is used to divide the branches, you need longer vein compared to cardiac surgery.
There's concern about inferior primary patency, and there are variable wound complications reported. So recent PAD data, there, in 2014, a review of the Society of Vascular Surgery registry, of 5000 patients, showed that continuous Open Vein Harvest
was performed 49% of the time and a Endo Vein Harvest about 13% of the time. The primary patency was 70%, for Continuous versus just under 59% for Endoscopic, and that was significant. Endoscopic Vein Harvest was found to be an independent risk factor for a lower one year
primary patency, in the study. And, the length of stay due to wounds was not significantly different. So, systematic review of Endoscopic Vein Harvest data in the lower extremity bypass from '96 to 2013 did show that this technique may reduce
primary patency with no change in wound complications. Reasons for decreased primary patency, inexperienced operator, increased electrocautery injury to the vein. Increase in vein manipulation, you can't do the no touch technique,
like you could do with an Open Harvest. You need a longer conduit. So, I do believe there's a roll for this, in the vascular surgeon's armamentarium. I would recommend, how I use it in my practices is, I'm fairly inexperienced with Endoscopic Vein Harvest,
so I do work with the cardiac PA's. With increased percutaneous procedures, my practice has seen decreased Saphenous Vein Bypasses, so, I've less volume to master the technique. If the PA is not available, or the conduit is small, I recommend an Open Vein Harvest.
The PA can decrease the labor required during these cases. So, it's sometimes nice to have help with these long cases. Close surveillance follow up with Non-Invasive Arterial Imaging is mandatory every three months for the first year at least. Thank you.
- Thank you for introduction. Thanks to Frank Veith for the kind invitation to present here our really primarily single-center experience on this new technique. This is my disclosure. So what you really want
in the thromboembolic acute events is a quick flow restoration, avoid lytic therapies, and reduce the risk of bleeding. And this can be achieved by surgery. However, causal directed local thrombolysis
is much less invasive and also give us a panoramic view and topographic view that is very useful in these cases. But it takes time and is statistically implied
and increases risk of bleeding. So theoretically percutaneous thrombectomy can accomplish all these tasks including a shorter hospital stay. So among the percutaneous thrombectomy devices the Indigo System is based on a really simple
aspiration mechanism and it has shown high success in ischemic stroke. This is one of my first cases with the Indigo System using a 5 MAX needle intervention
adapted to this condition. And it's very easy to understand how is fast and effective this approach to treat intraprocedural distal embolization avoiding potential dramatic clinical consequences, especially in cases like this,
the only one foot vessel. This is also confirmed by this technical note published in 2015 from an Italian group. More recently, other papers came up. This, for example, tell us that
there has been 85% below-the-knee primary endpoint achievement and 54% in above-the-knee lesions. The TIMI score after VAT significantly higher for BTK lesions and for ATK lesions
a necessity of a concomitant endovascular therapy. And James Benenati has already told us the results of the PRISM trials. Looking into our case data very quickly and very superficially we can summarize that we had 78% full revascularization.
In 42% of cases, we did not perform any lytic therapy or very short lytic therapy within three hours. And in 36% a long lytic therapy was necessary, however within 24 hours. We had also 22% failure
with three surgery necessary and one amputation. I must say that among this group of patients, twenty patients, there were also patients like this with extended thrombosis from the groin to the ankle
and through an antegrade approach, that I strongly recommend whenever possible, we were able to lower the aspiration of the clots also in the vessel, in the tibial vessels, leaving only this region, thrombosis
needed for additional three hour infusion of TPA achieving at the end a beautiful result and the patient was discharged a day after. However not every case had similar brilliant result. This patient went to surgery and he went eventually to amputation.
Why this? And why VAT perform better in BTK than in ATK? Just hypotheses. For ATK we can have unknown underlying chronic pathology. And the mismatch between the vessel and the catheter can be a problem.
In BTK, the thrombus is usually soft and short because it is an acute iatrogenic event. Most importantly is the thrombotic load. If it is light, no short, no lytic or short lytic therapy is necessary. Say if heavy, a longer lytic therapy and a failure,
regardless of the location of the thrombosis, must be expected. So moving to the other topic, venous occlusive thrombosis. This is a paper from a German group. The most exciting, a high success rate
without any adjunctive therapy and nine vessels half of them prosthetic branch. The only caution is about the excessive blood loss as a main potential complication to be checked during and after the procedure. This is a case at my cath lab.
An acute aortic renal thrombosis after a open repair. We were able to find the proximate thrombosis in this flush occlusion to aspirate close to fix the distal stenosis
and the distal stenosis here and to obtain two-thirds of the kidney parenchyma on both sides. And this is another patient presenting with acute mesenteric ischemia from vein thrombosis.
This device can be used also transsympatically. We were able to aspirate thrombi but after initial improvement, the patient condition worsened overnight. And the CT scan showed us a re-thrombosis of the vein. Probably we need to learn more
in the management of these patients especially under the pharmacology point of view. And this is a rapid overview on our out-of-lower-limb case series. We had good results in reimplanted renal artery, renal artery, and the pulmonary artery as well.
But poor results in brachial artery, fistula, and superior mesenteric vein. So in conclusion, this technology is an option for quick thromboembolic treatment. It's very effective for BTK intraprocedural embolic events.
The main advantage is a speeding up the blood flow and reestablishing without prolonged thrombolysis or reducing the dosage of the thrombolysis. Completely cleaning up extensive thromobosed vessels is impossible without local lytic therapies. This must be said very clearly.
Indigo technology is promising and effective for treatment of acute renovisceral artery occlusion and sub massive pulmonary embolism. Thank you for your attention. I apologize for not being able to stay for the discussion
because I have a flight in a few hours. Thank you very much.
- So I don't have to give you any data. I just have to tell you how we do it. So this is the easiest talk of this session. Step-by-step technical tips. Now our definition of pharmaco-mechanical may vary between us so I'll give that as we go along. These are my conflicts.
When to use it. Well certainly as you already heard, Massive PE has contraindication to full dose lytic is one area. Submassive elevated risk may be another. We've already seen multiple people put up
these guidelines so what we're really talking about at this point in time is those patients that we just talked, that those two groups that they just talked about because those are the ones that we're trying to treat. The biggest thing is don't be frozen by indecision.
Majority of patients eligible for thrombolysis do not receive it. It's amazing to me as a referral center to get the call from an outside community hospital or the patient with hypotension, abnormal RV or biomarkers and they've barely given the patient
Heparin and they just want to transfer the patient out of there and you tell them that's a massive PE. Please give them systemic thrombolysis and they go what? And I go you now have 10 times the death rate of an acute myocardial infarction. Would you give this patient lytics for acute MI?
Yes. Then give them the freaking lytics. Save their life. It's amazing what's going on in this country. So the PERT Consortium and everything, we really need to educate the community
because it's ridiculous. If you look at the utilization of thrombolysis, it's going down. Unbelievable and if you look at the in-hospital mortality for these patients that have significant PE, the in-hospital mortality is much higher
if you don't give thrombolysis. You've already seen this indirectly in a bunch of different lectures, but I just wanted to show you very quickly how to do this on an echo or CT. You want to get the center line, get it at the valve and then measure it one centimeter
below that valvular plane. This is something you don't have to depend on radiology just to do. You can just look at the transfer CT. You can look at the echo. You don't have to fight with your echo guy to give you that.
It's also very evident and often times just looking at the images. Why treat submassive elevated risk PE? You know what? I've heard all the mortality stuff. I get it.
It doesn't change mortality that much. It does and we should measure it as a primary endpoint in our trials. Change your discharge time and in this day and age, medicine is so expensive. Time in the hospital, repeat procedures,
elevated your amount of treatment for that patient really has to be looked at as part of that, not just mortality. But there's eight times more recurrent PE and four times a mortality rate if you have a PE and unresolved RV dysfunction at discharge
and that should be looked at prior to discharge, not just say well they look like they're doing okay. Treatment of IVC, higher risk PE. Certainly the other thing we have to look at is there's other things to do. You've already heard a little bit
that there's IVC filters out there. We take out 90 some percent of our IVC filters in our section. We actually as a system now are up to 60% at seven months and it only takes effort. The patients that I see die in our hospital
in the last year that shouldn't have died are patients that should've gotten an IVC filter because they got heroic things to take out their PE and nobody put a filter in even though they had significant DVT left over because they were afraid of the TV commercials?
Oh my gosh. If you look at the 27 extra deaths that we've had from IVC filters that were removable in the United States, and you take our experience and multiply it by the number of tertiary care hospitals in the United States, use them when they're appropriate.
Take them out so the risk is low, but don't go away from them. They've already been shown to be beneficial for the right patient population. But you also have embolectomy and surgery should also be considered.
Step by step. Make the decision and clinically be consistent. PERT team or other consistent mechanisms. We have an app that we use. This is throughout our entire healthcare system so all the vascular specialists have this.
It's an algorithm that's supposed to be used both in the ER and for the different vascular specialties so everybody's being treated very similarly. We have all the different definitions. We have the PESI calculator. All this is in an app
that's readily available to our constituents. Special consideration certainly is the tolerance of thrombolysis, underlying tolerance of pulmonary hypertension. Again, we need to evaluate the patient, not just label them as a PE.
And I also think there's a special population we need to study and that's the socked in pulmonary artery with no perfusion on a CT scan. I think this is a different population long term and we need to study that a little bit more. We got to get the patient back from the edge.
I think I'm opposite of Jeff. I don't want to see them get worse and then treat 'em. I want to prevent them from getting worse as long as I'm selecting that population in a thoughtful matter. We primarily use low dose TNK.
This is nothing I'm going to give you data on. This is an institutional, what do you want to call it, anecdotal experience and we lost our contracts except for TNK so we had to go to this and so we do a lot of catheter-directed. You've already seen all these trials.
There's a ton of different devices out there. The one I want to talk to you about is using a really fancy one called a pigtail catheter and another one called an ethos catheter. This is a patient that had a significant PE. You can see that they've got bilateral main PE.
This is on table. This is what we do for the vast majority of our patients. We sit there, we use ultrasound guided access to the vein so that we cut down our venous complications for access site. The patient is given 20 and 30% of a loading dose
of TNK and then we watch them. If you look at thrombus in a test tube and you give a thrombolytic therapy, it takes about 20 minutes for fibrinolysis. So this is what we do. As you're going to see, this is over 25 minutes
and we see the patient went from a pulmonary pressure of 65 and a heart rate of 115 down to 25 minutes, the patient's pulmonary pressure is about 44 and their heart rate is in the 90's. This patient then has all the catheters removed on the table even though they got lytic
and they're heparinized. This is a venipuncture, so big IV. We send them up to the unit and we typically discharge them the next day. We have an echo B4 discharge to make sure there's been a significant recovery of RV.
If not we'll watch them an extra day and then all these patients get a CT again. I'm sorry an echo again at 30 days to make sure that we're getting good resolution from that. On table results, decrease your complications. Thrombolysis has always been associated with the
duration of thrombolytic therapy and intracranial bleed. Now you can either use a pigtail catheter which is what we use for most of these people because we can measure pressure in it. We spin it around a little bit in the pulmonary arteries and give the dosage.
Again, we give 20-30% of the dose. There is no data for that. If significant improvement does not occur, they'll get dripped overnight in the ICU at usually .5 to 1 milligram per hour. You've already seen the data for EKOS.
We use this if we think we need a little bit quicker Thrombolysis such as in a socked in pulmonary artery 'cause we have no flow. We do think that may help, but we don't have any data for that. It makes us feel good.
We spend a lot more money and so we think that may be reasonable at that point in time. This is just what it looks like when you put in bilateral EKOS catheters. Certainly the patient can be put in the ICU for this. I do think that we should do a trial looking at EKOS
with a little higher dose, do it for 30 minutes, look at those pulmonary pressures right on the table. I think, again, my own opinion is after 25 years, the closer we get to being done on table, catheters out, patients doing well, the better, safer procedure we have,
the less chance of mortality, the less chance of complication and as you decrease complications, your benefit improves. We've already seen the results and you'll see more of these from non-randomized trials such as Seattle 2 which looked at 150 patients,
but they saw very quick recovery of the RV which was very important. If you look at technical success, it was very high. The dosage of thrombolytic exceedingly lower, lower than what we're giving in a PTO catheter, that's for sure.
And if you look at the RV from Ultima Trial which was randomized. There was faster RV recovery utilizing this device. Thank you very much.
Thanks very much, Tom. I'll be talking about thermal ablation on anticoagula is it safe and effective? I have no disclosures. As we know, extensive review of both RF and laser
ablation procedures have demonstrated excellent treatment effectiveness and durability in each modality, but there is less data regarding treatment effectiveness and durability for those procedures in patients who are also on systemic anticoagulation. As we know, there's multiple studies have been done
over the past 10 years, with which we're all most familiar showing a percent of the durable ablation, both modalities from 87% to 95% at two to five years. There's less data on those on the anticoagulation undergoing thermal ablation.
The largest study with any long-term follow up was by Sharifi in 2011, and that was 88 patients and follow-up at one year. Both RF and the EVLA had 100% durable ablation with minimal bleeding complications. The other studies were all smaller groups
or for very much shorter follow-up. In 2017, a very large study came out, looking at the EVLA and RF using 375 subjects undergoing with anticoagulation. But it was only a 30-day follow-up, but it did show a 30% durable ablation
at that short time interval. Our objective was to evaluate efficacy, durability, and safety of RF and EVLA, the GSV and the SSV to treat symptomatic reflux in patients on therapeutic anticoagulation, and this group is with warfarin.
The data was collected from NYU, single-center. Patients who had undergone RF or laser ablation between 2011 and 2013. Ninety-two vessels of patients on warfarin at the time of endothermal ablation were selected for study. That's the largest to date with some long-term follow-up.
And this group was compared to a matched group of 124 control patients. Devices used were the ClosureFast catheter and the NeverTouch kits by Angiodynamics. Technical details, standard IFU for the catheters. Tumescent anesthetic.
And fiber tips were kept about 2.5 centimeters from the SFJ or the SPJ. Vein occlusion was defined as the absence of blood flow by duplex scan along the length of the treated vein. You're all familiar with the devices, so the methods included follow-up, duplex ultrasound
at one week post-procedure, and then six months, and then also at a year. And then annually. Outcomes were analyzed with Kaplan-Meier plots and log rank tests. The results of the anticoagulation patients, 92,
control, 124, the mean follow-up was 470 days. And you can see that the demographics were rather similar between the two groups. There was some more coronary disease and hypertension in the anticoagulated groups, and that's really not much of a surprise
and some more male patients. Vessels treated, primarily GSV. A smaller amount of SSV in both the anticoagulated and the control groups. Indications for anticoagulation.
About half of the patients were in atrial fibrillation. Another 30% had a remote DVT in the contralateral limb. About 8% had mechanical valves, and 11% were for other reasons. And the results. The persistent vein ablation at 12 months,
the anticoagulation patients was 97%, and the controls was 99%. Persistent vein ablation by treated vessel, on anticoagulation. Didn't matter if it was GSV or SSV. Both had persistent ablation,
and by treatment modality, also did not matter whether it was laser or RF. Both equivalent. If there was antiplatelet therapy in addition to the anticoagulation, again if you added aspirin or Clopidogrel,
also no change. And that was at 12 months. We looked then at persistent vein ablation out at 18 months. It was still at 95% for the controls, and 91% for the anticoagulated patients. Still not statistically significantly different.
At 24 months, 89% in both groups. Although the numbers were smaller at 36 months, there was actually still no statistically significant difference. Interestingly, the anticoagulated group actually had a better persistent closure rate
than the control group. That may just be because the patients that come back at 36 months who didn't have anticoagulation may have been skewed. The ones we actually saw were ones that had a problem. It gets harder to have patients
come back at three months who haven't had an uneventful venous ablation procedure. Complication, no significant hematomas. Three patients had DVTs within 30 days. One anticoagulation patient had a popliteal DVT, and one control patient.
And one control patient had a calf vein DVT. Two EHITs. One GSV treated with laser on anticoagulation noted at six days, and one not on anticoagulation at seven days. Endovenous RF and EVLA can be safely performed
in patients undergoing long-term warfarin therapy. Our experience has demonstrated a similar short- and mid-term durability for RF ablation and laser, and platelet therapy does not appear to impact the closer rates,
which is consistent with the prior studies. And the frequency of vein recanalization following venous ablation procedures while on ACs is not worse compared to controls, and to the expected incidence as described in the literature.
This is the largest study to date with follow-up beyond 30 days with thermal ablation procedures on anticoagulation patients. We continue to look at these patients for even longer term durability. Thanks very much for your attention.
- Thank you Mr. Chairman. Ladies and gentleman, first of all, I would like to thank Dr. Veith for the honor of the podium. Fenestrated and branched stent graft are becoming a widespread use in the treatment of thoracoabdominal
and pararenal aortic aneurysms. Nevertheless, the risk of reinterventions during the follow-up of these procedures is not negligible. The Mayo Clinic group has recently proposed this classification for endoleaks
after FEVAR and BEVAR, that takes into account all the potential sources of aneurysm sac reperfusion after stent graft implant. If we look at the published data, the reported reintervention rate ranges between three and 25% of cases.
So this is still an open issue. We started our experience with fenestrated and branched stent grafts in January 2016, with 29 patients treated so far, for thoracoabdominal and pararenal/juxtarenal aortic aneurysms. We report an elective mortality rate of 7.7%.
That is significantly higher in urgent settings. We had two cases of transient paraparesis and both of them recovered, and two cases of complete paraplegia after urgent procedures, and both of them died. This is the surveillance protocol we applied
to the 25 patients that survived the first operation. As you can see here, we used to do a CT scan prior to discharge, and then again at three and 12 months after the intervention, and yearly thereafter, and according to our experience
there is no room for ultrasound examination in the follow-up of these procedures. We report five reinterventions according for 20% of cases. All of them were due to endoleaks and were fixed with bridging stent relining,
or embolization in case of type II, with no complications, no mortality. I'm going to show you a couple of cases from our series. A 66 years old man, a very complex surgical history. In 2005 he underwent open repair of descending thoracic aneurysm.
In 2009, a surgical debranching of visceral vessels followed by TEVAR for a type III thoracoabdominal aortic aneurysms. In 2016, the implant of a tube fenestrated stent-graft to fix a distal type I endoleak. And two years later the patient was readmitted
for a type II endoleak with aneurysm growth of more than one centimeter. This is the preoperative CT scan, and you see now the type II endoleak that comes from a left gastric artery that independently arises from the aneurysm sac.
This is the endoleak route that starts from a branch of the hepatic artery with retrograde flow into the left gastric artery, and then into the aneurysm sac. We approached this case from below through the fenestration for the SMA and the celiac trunk,
and here on the left side you see the superselective catheterization of the branch of the hepatic artery, and on the right side the microcatheter that has reached the nidus of the endoleak. We then embolized with onyx the endoleak
and the feeding vessel, and this is the nice final result in two different angiographic projections. Another case, a 76 years old man. In 2008, open repair for a AAA and right common iliac aneurysm.
Eight years later, the implant of a T-branch stent graft for a recurrent type IV thoracoabdominal aneurysm. And one year later, the patient was admitted again for a type IIIc endoleak, plus aneurysm of the left common iliac artery. This is the CT scan of this patient.
You will see here the endoleak at the level of the left renal branch here, and the aneurysm of the left common iliac just below the stent graft. We first treated the iliac aneurysm implanting an iliac branched device on the left side,
so preserving the left hypogastric artery. And in the same operation, from a bowl, we catheterized the left renal branch and fixed the endoleak that you see on the left side, with a total stent relining, with a nice final result on the right side.
And this is the CT scan follow-up one year after the reintervention. No endoleak at the level of the left renal branch, and nice exclusion of the left common iliac aneurysm. In conclusion, ladies and gentlemen, the risk of type I endoleak after FEVAR and BEVAR
is very low when the repair is planning with an adequate proximal sealing zone as we heard before from Professor Verhoeven. Much of reinterventions are due to type II and III endoleaks that can be treated by embolization or stent reinforcement. Last, but not least, the strict follow-up program
with CT scan is of paramount importance after these procedures. I thank you very much for your attention.
- [Bill] Thank you Vikay. I think this is an interesting topic for many reasons but one of the key ones is that if you look at our health care policies by insurers, this tends to define our practice. So I looked at BlueCross BlueShield's policy and they say that treatment of the GSV or SSV
is medically necessary when there is demonstrated saphenous reflux and I looked for more and there was no more. That's all they said so they must think that reflux a time correlates with venous severity. So is this true?
I think, personally, that there are other things that are involved and that volume is really the key. Time, velocity and the diameter of the vein are likely all part of the process and we all know that obstruction
is also critically important as well and probably the worse patients are those that have both reflux and obstruction. Probably reflux is worse in the deep system but we know that large GSV and SSV patients can develop CEAP four to six symptoms
and do very well with saphenous ablations. And I think this is a nice analogy. I love this guy, it looks like he came off of his lawn chair to help the firefighters out but he's probably not going to do so much with his little garden hose now, is he?
So I think size and velocity do matter. What does the literature tell us? Chris Lattimer and his group have done an elegant set of studies looking at how various parameters correlate to air plethysmography and venous filling times. They did show that there is a correlation
between venous filling time and reflux time. However, other things were probably more correlated such as GSV diameter and reflux velocity. And in this nice study of 300 patients they found that there was a relatively weak correlation between reflux time and clinical severity
and their conclusion was that it was a good parameter to identify reflux but not for quantifying the severity. So here's how we use this clinically in my practice. So you see many patients such as this that have mixed venous disease.
53-year-old female, severe edema. You do her studies and she's got reflux in the deep and the superficial system. So how to we decide if saphenous ablation is going to help this patient or not and correct these symptoms, prevent further ulcerations?
So all reflux is not created equal. The top is a popliteal tracing where the maximum reflux velocity is about five centimeters per second versus the bottom one that's about thirty to forty centimeters per second
so these probably aren't going to behave similarly in when we look at them. So we studied this in 75 patients and reported this back in 2008. We look at the maximum reflux velocity in the popliteal vein to tell if these patients
would improve after we ablated their saphenous or not. We found that this was a significant predictor of both improvement in venous filling index and the venous clinical severity score so we think velocity really does matter. And this is where we're seeing this clinically.
This is a patient that was referred to me for a second opinion concerning whether she would need ablation of her great saphenous vein. And this is the reflux tracing and you can see the scale here is turned up so that this is a measurement of reflux at about two centimeters per second.
This was used to document abnormal reflux and to justify ablation of the saphenous. So I checked one of our tracings. This is what it looks like.
- Thank you chairman, ladies and gentlemen. I have no conflict of interest for this talk. So, basically for vTOS we have the well known treatment options. Either the conservative approach with DOAC or anticoagulation for three months or longer supported by elastic stockings.
And alternatively there's the invasive approach with catheter thrombolysis and decompression surgery and as we've just heard in the talk but Ben Jackson, also in surgeons preference, additional PTA and continuation or not of anticoagulation.
And basically the chosen therapy is very much based on the specific specialist where the patient is referred to. Both treatment approaches have their specific complications. Rethrombosis pulmonary embolism,
but especially the post-thrombotic syndrome which is reported in conservative treatment in 26 up to 66%, but also in the invasive treatment approach up to 25%. And of course there are already well known complications related to surgery.
The problem is, with the current evidence, that it's only small retrospective studies. There is no comparative studies and especially no randomized trials. So basically there's a lack of high quality evidence leading to varying guideline recommendations.
And I'm not going through them in detail 'cause it's a rather busy slide. But if you take a quick look then you can see some disparencies between the different guidelines and at some aspects there is no recommendation at all,
or the guidelines refer to selected patients, but they define how they should be selected. So again, the current evidence is insufficient to determine the most clinically and cost effective treatment approach, and we believe that a randomized trial is warranted.
And this is the UTOPIA trial. And I'm going to take you a bit through the design. So the research question underline this trial is, does surgical treatment, consisting of catheter directed thrombolysis and first rib section, significantly reduce post-thrombotic syndrome
occurrence, as compared to conservative therapy with DOAC anticoagulation, in adults with primary upper extremity deep vein thrombosis? The design is multicenter randomized and the population is all adults with first case of primary Upper Extremity
Deep Venous Thrombosis. And our primary outcome is occurrence of post-thrombotic syndrome, and this the find according the modified Villalta score. And there are several secondary outcomes, which of course we will take into account,
such as procedural complications, but also quality of life. This is the trial design. Inclusion informed consent and randomization are performed at first presentation either with the emergency department or outpatient clinic.
When we look at patients 18 years or older and the symptoms should be there for less than 14 days. Exclusion criteria are relevant when there's a secondary upper extremity deep vein thrombosis or any contra-indication for DOACs or catheter directed thrombolysis.
We do perform imaging at baseline with a CT venography. We require this to compare baseline characteristics of both groups to mainly determine what the underlying cause of the thrombosis being either vTOS or idiopathic.
And then a patient follows the course of the trial either the invasive treatment with decompression surgery and thrombolysis and whether or not PTA is required or not, or conservative treatment and we have to prefer DOAC Rivaroxaban or apixaban to be used.
Further down the patient is checked for one month and the Villalta score is adapted for use in the upper extremity and we also apply quality of life scores and scores for cost effectiveness analysis. And this is the complete flowchart of the whole trial.
Again, very busy slide, but just to show you that the patient is followed up at several time points, one, three, six, and 12 months and the 12 months control is actually the endpoint of the trial
And then again, a control CT venography is performed. Sample size and power calculation. We believe that there's an effect size of 20% reduction in post-thrombotic syndrome in favor of the invasive treatment and there's a two-side p-value of 0.05
and at 80% power, we consider that there will be some loss to follow up, and therefore we need just over 150 patients to perform this trial. So, in short, this slide more or less summarize it. It shows the several treatment options
that are available for these patients with Upper Extremity Venous Thrombosis. And in the trial we want to see, make this comparison to see if anticoagulation alone is as best as invasive therapy. I thank for your attention.
- Thank you, Captain, and I'd like to thank Doctor Veith for the opportunity today to further this discussion about vascular injury care, specifically endovascular options that have continued to emerge and become a bigger part of our practice. Vascular trauma remains a challenging entity
for anyone who takes care of trauma patients, on the battlefield it accounts for 12% of our trauma incidents and it's the second leading cause of death in both civilian and military trauma. And some of the most challenging
are those non-compressible sites which represent a majority of those that we really struggle with. There are a number of involving technologies and approaches that have been applied to trauma, we were going to talk in other talks about
REBOA and some of those options. But for the purpose of the talk here, I'm really going to talk about endovascular stent grafts as emergent and definitive tool managements. These make sense for a variety of reasons,
endovascular is becoming a bigger part of the trauma toolkit because we've had a significant shift in elective and emergency vascular work towards endovascular surgery. Every trauma center now, if they don't have one, is developing a hybrid OR environment
which is capable of providing high-end endovascular care. And we have an increase in familiarity both among surgeons, IR providers, and a variety of providers who take care of these trauma patients. Unfortunately, however, we as of yet do not have
any trials yet to prove the practice is better than open approaches. But we do have some success stories. A blunt thoracic aortic injury, if you have to pick one, is certainly a success story in trauma. Everyone in this audience is familiar
with the way that this has evolved. This is just one of a number of studies including the two AAST Center studies in 2008 and 2009 by the Aortic Trauma Foundation recently published in 2015 which showed that TEVAR was associated with lower transfusion requirements,
lower overall mortality, and lower aortic-correlated mortality compared to traditional open-repair modalities. And in the time that these technologies have been introduced, they have really changed practice. But what about other locations?
We have a variety of other anatomic locations that historically and traditionally have been challenging surgical exposures, the carotid at the base of the skull, the thoracic inlet, all these represent challenging options for open repair amongst trauma surgeons.
We do have some good evidence that needs to be expanded and further built upon that carotid capabilities from an endovascular stent graph repair perspective, particularly for those injuries at the base of the skull can be performed with a reasonable modicum of success. And with good followup to two weeks to two years,
patency rates are about 80% with low appreciable neurologic deficits after stent placement. Axillo-subclavian injuries represent another challenging open exposure for most trauma surgeons and an opportunity for vascular surgeons to introduce some more effective endovascular
stent graft technologies for application. Just one paper here from a myriad of trauma centers, a collaboration conducted by Doctor Branco, who showed that endovascular repair with injuries at these locations was associated with significantly lower mortality,
lower rates of surgical site infections, and a trend toward lower sepsis rates. And when you look overall at the invasion, if you will, of endovascular technologies this was a very nice review from a national trauma data bank of the American College of Surgeons,
which was conducted over nine years and over 40,000 vascular injuries. And you can see there, over time, we have seen a significant increase in use of endovascular procedures to deal with these injuries. I would say now that that is based upon data
from the PROOVIT Registry that is now roughly 20% of all vascular injuries have some endovascular technology applied. And these resulted in lowering hospital mortality following endovascular intervention and lower complication rate trends.
This is the most recent review, conducted by one of our visiting fellows when I was at David Grant, Major Robert Faulconer was a review of the AAST, or American Association for the Surgery of Trauma, perspective observational vascular injury treatment trial,
or called PROOVIT for short. And just very briefly, the punchline from this examination was that favorable outcomes were observed when arterial injury at non-compressible sites of truncal hemorrhage was managed with endovascular approaches.
The endovascular group, despite being more severely injured, had a lower mortality and a lower packed red blood cell requirement. And we're also learning that these technologies can be applied in hybrid techniques. This is just a simple example of a case
that was encountered at my own institution, this was a young man who had a gun shot wound through the right iliac artery and vein. He had an attempted interposition repair which blew out in the setting of small bowel contamination from associated bowel injury.
And we were really left with a very challenging situation in a patient who was physiologically depleted and would not tolerate a repeat definitive repair. And very little tissue to roll over the graft. So what we selected to do was what is known as a direct stent endo graft repair, or DSER.
And we basically bridged this gap with an endovascular stent graft utilizing the radial force to create a space for repair and not having a suture line now at risk in this contaminated field. This patient did quite well and
is now six months out with good results. This has been written about by several individuals and investigators to explain the use of stent grafts not only as a proxy or replacement for the typical plastic argyle shunt options, but these can actually potentially
become left in place when you come back for the repeat damage control surgery after initial repair. You can cover this with tissue graft and you now have a sutureless repair that is not prone to blow out as many of these injuries are in contaminated fields. Lots of unresolved issues with the investigation
and continued research in vascular traumas, particularly as it relates to endovascular graft repairs. Patient selection, we deal with young patients, small vessels, that natural history's not well established, anticoagulation and the definitive role of endovascular at a variety of locations is not well defined.
I mentioned the PROOVIT Registry, this has been going on for a number of years. It captures in-hospital outcomes and outpatient module questions. We do hope that this was able to answer some of the significant questions that we have in this area.
As of this month, we have over 4,000 patients in 27 centers, we still invite others to participate if anyone in the audience is interested. And we have a variety of issues we have already examined and will continue to examine in hopes that we can answer many of the questions
related to the optimal treatment of vascular injury. Thank you.
- This talk is a brief one about what I think is an entity that we need to be aware of because we see some. They're not AVMs obviously, they're acquired, but it nevertheless represents an entity which we've seen. We know the transvenous treatment of AVMs is a major advance in safety and efficacy.
And we know that the venous approach is indeed very, very favorable. This talk relates to some lesions, which we are successful in treating as a venous approach, but ultimately proved to be,
as I will show you in considerable experience now, I think that venous thrombosis and venous inflammatory disease result in acquired arteriovenous connections, we call them AVMs, but they're not. This patient, for example,
presented with extensive lower extremity swelling after an episode of DVT. And you can see the shunting there in the left lower extremity. Here we go in a later arterial phase. This lesion we found,
as others, is best treated. By the way, that was his original episode of DVT with occlusion. Was treated with stenting and restoration of flow and the elimination of the AVM.
So, compression of the lesion in the venous wall, which is actually interesting because in the type perivenous predominant lesions, those are actually lesions in the vein wall. So these in a form, or in a way, assimilate the AVMs that occur in the venous wall.
Another man, a 53-year-old gentleman with leg swelling after an episode of DVT, we can see the extensive filling via these collaterals, and these are inflammatory collaterals in the vein wall. This is another man with a prior episode of DVT. See his extensive anterior pelvic collaterals,
and he was treated with stenting and success. A recent case, that Dr. Resnick and I had, I was called with a gentleman said he had an AVM. And we can see that the arteriogram sent to me showed arterial venous shunting.
Well, what was interesting here was that the history had not been obtained of a prior total knee replacement. And he gave a very clear an unequivocal history of a DVT of sudden onset. And you can see the collaterals there
in the adjacent femoral popliteal vein. And there it is filling. So treatment here was venous stenting of the lesion and of the underlying stenosis. We tried an episode of angioplasty,
but ultimately successful. Swelling went down and so what you have is really a post-inflammatory DVT. Our other vast experience, I would say, are the so-called uterine AVMs. These are referred to as AVMs,
but these are clearly understood to be acquired, related to placental persistence and the connections between artery and veins in the uterus, which occurs, a part of normal pregnancy. These are best treated either with arterial embolization, which has been less successful,
but in some cases, with venous injection in venous thrombosis with coils or alcohol. There's a subset I believe of some of our pelvic AVMs, that have histories of DVT. I believe they're silent. I think the consistency of this lesion
that I'm showing you here, that if we all know, can be treated by coil embolization indicates to me that at least some, especially in patients in advanced stage are related to DVT. This is a 56-year-old, who had a known history of prostate cancer
and post-operative DVT and a very classic looking AVM, which we then treated with coil embolization. And we're able to cure, but no question in my mind at least based on the history and on the age, that this was post-phlebitic.
And I think some of these, and I think Wayne would agree with me, some of these are probably silent internal iliac venous thromboses, which we know can occur, which we know can produce pulmonary embolism.
And that's the curative final arteriogram. Other lesions such as this, I believe are related, at least some, although we don't have an antecedent history to the development of DVT, and again of course,
treated by the venous approach with cure. And then finally, some of the more problematic ones, another 56-year-old man with a history of prior iliofemoral DVT. Suddenly was fine, had been treated with heparin and anticoagulation.
And suddenly appeared with rapid onset of right lower extremity swelling and pain. So you see here that on an arteriogram of the right femoral, as well as, the super selective catheterization of some of these collaterals.
We can see the lesion itself. I think it's a nice demonstration of lesion. Under any other circumstance, this is an AVM. It is an AVM, but we know it to be acquired because he had no such swelling. This was treated in the only way I knew how to treat
with stenting of the vein. We placed a stent. That's a ballon expanded in the angiogram on your right is after with ballon inflation. And you can see the effect that the stenting pressure, and therefore subsequently occlusion of the compression,
and occlusion of the collaterals, and connections in the vein wall. He subsequently became asymptomatic. We had unfortunately had to stent extensively in the common femoral vein but he had an excellent result.
So I think pelvic AVMs are very similar in location and appearance. We've had 13 cases. Some with a positive history of DVT. I believe many are acquired post-DVT, and the treatment is the same venous coiling and or stent.
Wayne has seen some that are remarkable. Remember Wayne we saw at your place? A guy was in massive heart failure and clearly a DVT-related. So these are some of the cases we've seen
and I think it's noteworthy to keep in mind, that we still don't know everything there is to know about AVMs. Some AVMs are acquired, for example, pelvic post-DVT, and of course all uterine AVMs. Thanks very much.
(audience applause) - [Narrator] That's a very interesting hypothesis with a pelvic AVMs which are consistently looking similar. - [Robert] In the same place right? - [Narrator] All of them are appearing at an older age. - [Robert] Yep.
Yep. - This would be a very, very good explanation for that. I've never thought about that. - Yeah I think-- - I think this is very interesting. - [Robert] And remember, exactly.
And I remember that internal iliac DVT is always a silent process, and that you have this consistency, that I find very striking. - [Woman] So what do you think the mechanism is? The hypervascularity looked like it was primarily
arterial fluffy vessels. - [Robert] No, no, no it's in the vein wall. If you look closely, the arteriovenous connections and the hypervascularity, it's in the vein wall. The lesion is the vein wall,
it's the inflammatory vein. You remember Tony, that the thing that I always think of is how we used to do plain old ballon angioplasty in the SFA. And afterwards we'd get this
florid venous filling sometimes, not every case. And that's the very tight anatomic connection between those two. That's what I think is happening. Wayne? - [Wayne] This amount is almost always been here.
We just haven't recognized it. What has been recognized is dural fistula-- - Yep. - That we know and that's been documented. Chuck Kerber, wrote the first paper in '73 about the microvascular circulation
in the dural surface of the dural fistula, and it's related to venous thrombosis and mastoiditis and trauma. And then as the healing process occurs, you have neovascular stimulation and fistulization in that dural reflection,
which is a vein wall. And the same process happens here with a DVT with the healing, the recanalization, inflammation, neovascular stimulation, and the development of fistulas. increased vascular flow into the lumen
of the thrombosed area. So it's a neovascular stimulation phenomenon, that results in the vein wall developing fistula very identical to what happens in the head with dural fistula had nothing described of in the periphery.
- [Narrator] Okay, very interesting hypothesis.
- Thank you. I have two talks because Dr. Gaverde, I understand, is not well, so we- - [Man] Thank you very much. - We just merged the two talks. All right, it's a little joke. For today's talk we used fusion technology
to merge two talks on fusion technology. Hopefully the rest of the talk will be a little better than that. (laughs) I think we all know from doing endovascular aortic interventions
that you can be fooled by the 2D image and here's a real life view of how that can be an issue. I don't think I need to convince anyone in this room that 3D fusion imaging is essential for complex aortic work. Studies have clearly shown it decreases radiation,
it decreases fluoro time, and decreases contrast use, and I'll just point out that these data are derived from the standard mechanical based systems. And I'll be talking about a cloud-based system that's an alternative that has some advantages. So these traditional mechanical based 3D fusion images,
as I mentioned, do have some limitations. First of all, most of them require manual registration which can be cumbersome and time consuming. Think one big issue is the hardware based tracking system that they use. So they track the table rather than the patient
and certainly, as the table moves, and you move against the table, the patient is going to move relative to the table, and those images become unreliable. And then finally, the holy grail of all 3D fusion imaging is the distortion of pre-operative anatomy
by the wires and hardware that are introduced during the course of your procedure. And one thing I'd like to discuss is the possibility that deep machine learning might lead to a solution to these issues. How does 3D fusion, image-based 3D fusion work?
Well, you start, of course with your pre-operative CT dataset and then you create digitally reconstructed radiographs, which are derived from the pre-op CTA and these are images that resemble the fluoro image. And then tracking is done based on the identification
of two or more vertebral bodies and an automated algorithm matches the most appropriate DRR to the live fluoro image. Sounds like a lot of gobbledygook but let me explain how that works. So here is the AI machine learning,
matching what it recognizes as the vertebral bodies from the pre-operative CT scan to the fluoro image. And again, you get the CT plus the fluoro and then you can see the overlay with the green. And here's another version of that or view of that.
You can see the AI machine learning, identifying the vertebral bodies and then on your right you can see the fusion image. So just, once again, the AI recognizes the bony anatomy and it's going to register the CT with the fluoro image. It tracks the patient, not the table.
And the other thing that's really important is that it recognizes the postural change that the patient undergoes between the posture during the CT scan, versus the posture on the OR table usually, or often, under general anesthesia. And here is an image of the final overlay.
And you can see the visceral and renal arteries with orange circles to identify them. You can remove those, you can remove any of those if you like. This is the workflow. First thing you do is to upload the CT scan to the cloud.
Then, when you're ready to perform the procedure, that is downloaded onto the medical grade PC that's in your OR next to your fluoro screen, and as soon as you just step on the fluoro pedal, the CYDAR overlay appears next to your, or on top of your fluoro image,
next to your regular live fluoro image. And every time you move the table, the computer learning recognizes that the images change, and in a couple of seconds, it replaces with a new overlay based on the obliquity or table position that you have. There are some additional advantages
to cloud-based technology over mechanical technology. First of all, of course, or hardware type technology. Excuse me. You can upgrade it in real time as opposed to needing intermittent hardware upgrades. Works with any fluoro equipment, including a C-arm,
so you don't have to match your 3D imaging to the brand of your fluoro imaging. And there's enhanced accuracy compared to mechanical registration systems as imaging. So what are the clinical applications that this can be utilized for?
Fluoroscopy guided endovascular procedures in the lower thorax, abdomen, and pelvis, so that includes EVAR and FEVAR, mid distal TEVAR. At present, we do need two vertebral bodies and that does limit the use in TEVAR. And then angioplasty stenting and embolization
of common iliac, proximal external and proximal internal iliac artery. Anything where you can acquire a vertebral body image. So here, just a couple of examples of some additional non EVAR/FEVAR/TEVAR applications. This is, these are some cases
of internal iliac embolization, aortoiliac occlusion crossing, standard EVAR, complex EVAR. And I think then, that the final thing that I'd like to talk about is the use with C-arm, which is think is really, extremely important.
Has the potential to make a very big difference. All of us in our larger OR suites, know that we are short on hybrid availability, and yet it's difficult to get our institutions to build us another hybrid room. But if you could use a high quality 3D fusion imaging
with a high quality C-arm, you really expand your endovascular capability within the operating room in a much less expensive way. And then if you look at another set of circumstances where people don't have a hybrid room at all, but do want to be able to offer standard EVAR
to their patients, and perhaps maybe even basic FEVAR, if there is such a thing, and we could use good quality imaging to do that in the absence of an actual hybrid room. That would be extremely valuable to be able to extend good quality care
to patients in under-served areas. So I just was mentioning that we can use this and Tara Mastracci was talking yesterday about how happy she is with her new room where she has the use of CYDAR and an excellent C-arm and she feels that she is able to essentially run two rooms,
two hybrid rooms at once, using the full hybrid room and the C-arm hybrid room. Here's just one case of Dr. Goverde's. A vascular case that he did on a mobile C-arm with aortoiliac occlusive disease and he places kissing stents
using a CYDAR EV and a C-arm. And he used five mils of iodinated contrast. So let's talk about a little bit of data. This is out of Blain Demorell and Tara Mastrachi's group. And this is use of fusion technology in EVAR. And what they found was that the use of fusion imaging
reduced air kerma and DSA runs in standard EVAR. We also looked at our experience recently in EVAR and FEVAR and we compared our results. Pre-availability of image based fusion CT and post image based fusion CT. And just to clarify,
we did have the mechanical product that Phillip's offers, but we abandoned it after using it a half dozen times. So it's really no image fusion versus image fusion to be completely fair. We excluded patients that were urgent/emergent, parallel endographs, and IBEs.
And we looked at radiation exposure, contrast use, fluoro time, and procedure time. The demographics in the two groups were identical. We saw a statistically significant decrease in radiation dose using image based fusion CT. Statistically a significant reduction in fluoro time.
A reduction in contrast volume that looks significant, but was not. I'm guessing because of numbers. And a significantly different reduction in procedure time. So, in conclusion, image based 3D fusion CT decreases radiation exposure, fluoro time,
and procedure time. It does enable 3D overlays in all X-Ray sets, including mobile C-arm, expanding our capabilities for endovascular work. And image based 3D fusion CT has the potential to reduce costs
and improve clinical outcomes. Thank you.
- Relevant disclosures are shown in this slide. So when we treat patients with Multi-Segment Disease, the more segments that are involved, the more complex the outcomes that we should expect, with regards to the patient comorbidities and the complexity of the operation. And this is made even more complex
when we add aortic dissection to the patient population. We know that a large proportion of patients who undergo Thoracic Endovascular Aortic Repair, require planned coverage of the left subclavian artery. And this also been demonstrated that it's an increase risk for stroke, spinal cord ischemia and other complications.
What are the options when we have to cover the left subclavian artery? Well we can just cover the artery, we no that. That's commonly performed in emergency situations. The current standard is to bypass or transpose the artery. Or provide a totally endovascular revascularization option
with some off-label use , such as In Situ or In Vitro Fenestration, Parallel Grafting or hopefully soon we will see and will have available branched graft devices. These devices are currently investigational and the focus today's talk will be this one,
the Valiant Mona Lisa Stent Graft System. Currently the main body device is available in diameters between thirty and forty-six millimeters and they are all fifteen centimeters long. The device is designed with flexible cuff, which mimics what we call the "volcano" on the main body.
It's a pivotal connection. And it's a two wire pre-loaded system with a main system wire and a wire through the left subclavian artery branch. And this has predominately been delivered with a through and through wire of
that left subclavian branch. The system is based on the valiant device with tip capture. The left subclavian artery branch is also unique to this system. It's a nitinol helical stent, with polyester fabric. It has a proximal flare,
which allows fixation in that volcano cone. Comes in three diameters and they're all the same length, forty millimeters, with a fifteen french profile. The delivery system, which is delivered from the groin, same access point as the main body device. We did complete the early feasibility study
with nine subjects at three sites. The goals were to validate the procedure, assess safety, and collect imaging data. We did publish that a couple of years ago. Here's a case demonstration. This was a sixty-nine year old female
with a descending thoracic aneurysm at five and a half centimeters. The patient's anatomy met the criteria. We selected a thirty-four millimeter diameter device, with a twelve millimeter branch. And we chose to extend this repair down to the celiac artery
in this patient. The pre-operative CT scan looks like this. The aneurysm looks bigger with thrombus in it of course, but that was the device we got around the corner of that arch to get our seal. Access is obtained both from the groin
and from the arm as is common with many TEVAR procedures. Here we have the device up in the aorta. There's our access from the arm. We had a separate puncture for a "pigtail". Once the device is in position, we "snare" the wire, we confirm that we don't have
any "wire wrap". You can see we went into a areal position to doubly confirm that. And then the device is expanded, and as it's on sheath, it does creep forward a bit. And we have capture with that through and through wire
and tension on that through and through wire, while we expand the rest of the device. And you can see that the volcano is aligned right underneath the left subclavian artery. There's markers there where there's two rings, the outer and the inner ring of that volcano.
Once the device is deployed with that through and through wire access, we deliver the branch into the left subclavian artery. This is a slow deployment, so that we align the flair within the volcano and that volcano is flexible. In some patients, it sort of sits right at the level of
the aorta, like you see in this patient. Sometimes it protrudes. It doesn't really matter, as long as the two things are mated together. There is some flexibility built in the system. In this particular patient,
we had a little leak, so we were able to balloon this as we would any others. For a TEVAR, we just balloon both devices at the same time. Completion Angiogram shown here and we had an excellent result with this patient at six months and at a year the aneurysm continued
to re-sorb. In that series, we had successful delivery and deployment of all the devices. The duration of the procedure has improved with time. Several of these patients required an extension. We are in the feasibility phase.
We've added additional centers and we continue to enroll patients. And one of the things that we've learned is that details about the association between branches and the disease are critical. And patient selection is critical.
And we will continue to complete enrollment for the feasibility and hopefully we will see the pivotal studies start soon. Thank you very much
- [Speaker] Good morning everybody thanks for attending the session and again thanks for the invitation. These are my disclosures. I will start by illustrating one of the cases where we did not use cone beam CT and evidently there were numerous mistakes on this
from planning to conducting the case. But we didn't notice on the completion of geography in folding of the stent which was very clearly apparent on the first CT scan. Fortunately we were able to revise this and have a good outcome.
That certainly led to unnecessary re intervention. We have looked at over the years our usage of fusion and cone beam and as you can see for fenestrated cases, pretty much this was incorporated routinely in our practice in the later part of the experience.
When we looked at the study of the patients that didn't have the cone beam CT, eight percent had re intervention from a technical problem that was potentially avoidable and on the group that had cone beam CT, eight percent had findings that were immediately revised with no
re interventions that were potentially avoidable. This is the concept of our GE Discovery System with fusion and the ability to do cone beam CT. Our protocol includes two spins. First we do one without contrast to evaluate calcification and other artifacts and also to generate a rotational DSA.
That can be also analyzed on axial coronal with a 3D reconstruction. Which essentially evaluates the segment that was treated, whether it was the arch on the arch branch on a thoracoabdominal or aortoiliac segment.
We have recently conducted a prospective non-randomized study that was presented at the Vascular Annual Meeting by Dr. Tenario. On this study, we looked at findings that were to prompt an immediate re intervention that is either a type one
or a type 3 endoleak or a severe stent compression. This was a prospective study so we could be judged for being over cautious but 25% of the procedures had 52 positive findings. That included most often a stent compression or kink in 17% a type one or three endoleak
in 9% or a minority with dissection and thrombus. Evidently not all this triggered an immediate revision, but 16% we elected to treat because we thought it was potentially going to lead to a bad complication. Here is a case where on the completion selective angiography
of the SMA this apparently looks very good without any lesions. However on the cone beam CT, you can see on the axial view a dissection flap. We immediately re catheterized the SMA. You note here there is abrupt stop of the SMA.
We were unable to catheterize this with a blood wire. That led to a conversion where after proximal control we opened the SMA. There was a dissection flap which was excised using balloon control in the stent as proximal control.
We placed a patch and we got a good result with no complications. But considerably, if this patient was missed in the OR and found hours after the procedure he would have major mesenteric ischemia. On this study, DSA alone would have missed
positive findings in 34 of the 43 procedures, or 79% of the procedures that had positive findings including 21 of the 28 that triggered immediate revision. There were only four procedures. 2% had additional findings on the CT
that were not detectable by either the DSA or cone beam CT. And those were usually in the femoro puncture. For example one of the patients had a femoro puncture occlusion that was noted immediately by the femoro pulse.
The DSA accounts for approximately 20% of our total radiation dose. However, it allows us to eliminate CT post operatively which was done as part of this protocol, and therefore the amount of radiation exposed for the patient
was decreased by 55-65% in addition to the cost containment of avoiding this first CT scan in our prospective protocol. In conclusion cone beam CT has allowed immediate assessment to identify technical problems that are not easily detectable by DSA.
These immediate revisions may avoid unnecessary re interventions. What to do if you don't have it? You have to be aware that this procedure that are complex, they are bound to have some technical mistakes. You have to have incredible attention to detail.
Evidently the procedures can be done, but you would have to have a low threshold to revise. For example a flared stent if the dilator of the relic gleam or the dilator of you bifurcated devise encroach the stent during parts of the procedure. Thank you very much.
- So Beyond Vascular procedures, I guess we've conquered all the vascular procedures, now we're going to conquer the world, so let me take a little bit of time to say that these are my conflicts, while doing that, I think it's important that we encourage people to access the hybrid rooms,
It's much more important that the tar-verse done in the Hybrid Room, rather than moving on to the CAT labs, so we have some idea basically of what's going on. That certainly compresses the Hybrid Room availability, but you can't argue for more resources
if the Hybrid Room is running half-empty for example, the only way you get it is by opening this up and so things like laser lead extractions or tar-verse are predominantly still done basically in our hybrid rooms, and we try to make access for them. I don't need to go through this,
you've now think that Doctor Shirttail made a convincing argument for 3D imaging and 3D acquisition. I think the fundamental next revolution in surgery, Every subspecialty is the availability of 3D imaging in the operating room.
We have lead the way in that in vascular surgery, but you think how this could revolutionize urology, general surgery, neurosurgery, and so I think it's very important that we battle for imaging control. Don't give your administration the idea that
you're going to settle for a C-arm, that's the beginning of the end if you do that, this okay to augment use C-arms to augment your practice, but if you're a finishing fellow, you make sure you go to a place that's going to give you access to full hybrid room,
otherwise, you are the subservient imagers compared to radiologists and cardiologists. We need that access to this high quality room. And the new buzzword you're going to hear about is Multi Modality Imaging Suites, this combination of imaging suites that are
being put together, top left deserves with MR, we think MR is the cardiovascular imaging modality of the future, there's a whole group at NIH working at MR Guided Interventions which we're interested in, and the bottom right is the CT-scan in a hybrid op
in a hybrid room, this is actually from MD Anderson. And I think this is actually the Trauma Room of the future, makes no sense to me to take a patient from an emergency room to a CT scanner to an and-jure suite to an operator it's the most dangerous thing we do
with a trauma patient and I think this is actually a position statement from the Trauma Society we're involved in, talk about how important it is to co-localize this imaging, and I think the trauma room of the future is going to be an and-jure suite
down with a CT scanner built into it, and you need to be flexible. Now, the Empire Strikes Back in terms of cloud-based fusion in that Siemans actually just released a portable C-arm that does cone-beam CT. C-arm's basically a rapidly improving,
and I think a lot of these things are going to be available to you at reduced cost. So let me move on and basically just show a couple of examples. What you learn are techniques, then what you do is look for applications to apply this, and so we've been doing
translumbar embolization using fusion and imaging guidance, and this is a case of one of my partners, he'd done an ascending repair, and the patient came back three weeks later and said he had sudden-onset chest pain and the CT-scan showed that there was a
sutured line dehiscence which is a little alarming. I tried to embolize that endovascular, could not get to that tiny little orifice, and so we decided to watch it, it got worse, and bigger, over the course of a week, so clearly we had to go ahead and basically and fix this,
and we opted to use this, using a new guidance system and going directly parasternal. You can do fusion of blood vessels or bones, you can do it off anything you can see on flu-roid, here we actually fused off the sternal wires and this allows you to see if there's
respiratory motion, you can measure in the workstation the depth really to the target was almost four and a half centimeters straight back from the second sternal wire and that allowed us really using this image guidance system when you set up what's called the bullseye view,
you look straight down the barrel of a needle, and then the laser turns on and the undersurface of the hybrid room shows you where to stick the needle. This is something that we'd refined from doing localization of lung nodules
and I'll show you that next. And so this is the system using the C-star, we use the breast, and the localization needle, and we can actually basically advance that straight into that cavity, and you can see once you get in it,
we confirmed it by injecting into it, you can see the pseudo-aneurism, you can see the immediate stain of hematoma and then we simply embolize that directly. This is probably safer than going endovascular because that little neck protects about
the embolization from actually taking place, and you can see what the complete snan-ja-gram actually looked like, we had a pig tail in the aura so we could co-linearly check what was going on and we used docto-gramming make sure we don't have embolization.
This patient now basically about three months follow-up and this is a nice way to completely dissolve by avoiding really doing this. Let me give you another example, this actually one came from our transplant surgeon he wanted to put in a vas,
he said this patient is really sick, so well, by definition they're usually pretty sick, they say we need to make a small incision and target this and so what we did was we scanned the vas, that's the hardware device you're looking at here. These have to be
oriented with the inlet nozzle looking directly into the orifice of the mitro wall, and so we scanned the heart with, what you see is what you get with these devices, they're not deformed, we take a cell phone and implant it in your chest,
still going to look like a cell phone. And so what we did, image fusion was then used with two completely different data sets, it mimicking the procedure, and we lined this up basically with a mitro valve, we then used that same imaging guidance system
I was showing you, made a little incision really doing onto the apex of the heart, and to the eur-aph for the return cannula, and this is basically what it looked like, and you can actually check the efficacy of this by scanning the patient post operatively
and see whether or not you executed on this basically the same way, and so this was all basically developed basing off Lung Nodule Localization Techniques with that we've kind of fairly extensively published, use with men can base one of our thoracic surgeons
so I'd encourage you to look at other opportunities by which you can help other specialties, 'cause I think this 3D imaging is going to transform what our capabilities actually are. Thank you very much indeed for your attention.
- I'm going to take it slightly beyond the standard role for the VBX and use it as we use it now for our fenestrated and branch and chimney grafts. These are my disclosures. You've seen these slides already, but the flexibility of VBX really does give us a significant ability to conform it
to the anatomies that we're dealing with. It's a very trackable stent. It doesn't, you don't have to worry about it coming off the balloon. Flexible as individual stents and in case in a PTFE so you can see it really articulates
between each of these rings of PTFE, or rings of stent and not connected together. I found I can use the smaller grafts, the six millimeter, for parallel grafts then flare them distally into my landing zone to customize it but keep the gutter relatively small
and decrease the instance of gutter leaks. So let's start with a presentation. I know we just had lunch so try and shake it up a little bit here. 72-year-old male that came in, history of a previous end-to-side aortobifemoral bypass graft
and then came in, had bilateral occluded external iliac arteries. I assume that's for the end-to-side anastomosis. I had a history of COPD, coronary artery disease, and peripheral arterial disease, and presented with a pseudoaneurysm
in the proximal juxtarenal graft anastomosis. Here you can see coming down the thing of most concern is both iliacs are occluded, slight kink in the aortofemoral bypass graft, but you see a common iliac coming down to the hypogastric, and that's really the only blood flow to the pelvis.
The aneurysm itself actually extended close to the renal, so we felt we needed to do a fenestrated graft. We came in with a fenestrated graft. Here's the renal vessels here, SMA. And then we actually came in from above in the brachial access and catheterized
the common iliac artery going down through the stenosis into the hypogastric artery. With that we then put a VBX stent graft in there which nicely deployed that, and you can see how we can customize the stent starting with a smaller stent here
and then flaring it more proximal as we move up through the vessel. With that we then came in and did our fenestrated graft. You can see fenestrations. We do use VBX for a good number of our fenestrated grafts and here you can see the tailoring.
You can see where a smaller artery, able to flare it at the level of the fenestration flare more for a good seal. Within the fenestration itself excellent flow to the left. We repeated the procedure on the right. Again, more customizable at the fenestration and going out to the smaller vessel.
And then we came down and actually extended down in a parallel graft down into that VBX to give us that parallel graft perfusion of the pelvis, and thereby we sealed the pseudoaneurysm and maintain tail perfusion of the pelvis and then through the aortofemoral limbs
to both of the common femoral arteries, and that resolved the pseudoaneurysm and maintained perfusion for us. We did a retrospective review of our data from August of 2014 through March of 2018. We had 183 patients who underwent endovascular repair
for a complex aneurysm, 106 which had branch grafts to the renals and the visceral vessels for 238 grafts. When we look at the breakdown here, of those 106, 38 patients' stents involved the use of VBX. This was only limited by the late release of the VBX graft.
And so we had 68 patients who were treated with non-VBX grafts. Their other demographics were very similar. We then look at the use, we were able to use some of the smaller VBXs, as I mentioned, because we can tailor it more distally
so you don't have to put a seven or eight millimeter parallel graft in, and with that we found that we had excellent results with that. Lower use of actual number of grafts, so we had, for VBX side we only had one graft
per vessel treated. If you look at the other grafts, they're anywhere between 1.2 and two grafts per vessel treated. We had similar mortality and followup was good with excellent graft patency for the VBX grafts.
As mentioned, technical success of 99%, mimicking the data that Dr. Metzger put forward to us. So in conclusion, I think VBX is a safe and a very versatile graft we can use for treating these complex aneurysms for perfusion of iliac vessels as well as visceral vessels
as we illustrated. And we use it for aortoiliac occlusive disease, branch and fenestrated grafts and parallel grafts. It's patency is equal to if not better than the similar grafts and has a greater flexibility for modeling and conforming to the existing anatomy.
Thank you very much for your attention.
- The main results of the mid-term, I would call it rather than long-term, there were three years of the improved trial, were published almost immediately after the Veith Symposium last year. I have no disclosures other than to say this was a great team effort, and it wasn't just me,
it was all the many contributors to this project. I think the important thing to start with is to understand the design. This was a randomized trial of unselected patients with a clinical diagnosis of ruptured abdominal aortic aneurysm.
The trial was to investigate whether EVAR as a first option, or an endovascular strategy, would save lives compared with open repair. We randomized 613 patients quite quickly across 30 centers, and this comprised 67 percent of those who would have been eligible for this trial, so good external validity.
Survival was the primary outcome for this trial. This was assessed at 30 days, one, and three years. At 30 days as you can see there was no difference between the endovascular strategy group in blue, and the open repair group in red. However, already at 30 days we noticed
that of the discharges in the endovascular strategy group, 97 percent of these went home, versus only 77 percent in the open repair group. No significant difference in survival at one year, but now out at three years, the survival is 56 percent in the endovascular strategy
group versus 48 percent in the open repair group. This is not quite significant. If we look only at the 502 patients who actually had a repair of a rupture, the benefits of the endovascular strategy are much stronger. And a compliance analysis,
because there were some crossovers in this pragmatic trial, shows very similar results. And for the 133 women, these were the real beneficiaries of an endovascular strategy. The cumulative incidence of re-interventions to three years are shown here, and no difference between open
and endovascular strategy. And I'll dwell on these in more detail in a later presentation. But this did mean that there was no additional cost to the endovascular strategy over the three year period. I'd also like to point out to you that
apart from the re-interventions, the need for renal support in the early days was 50 percent more common after open repair. Patients had rather different concerns about their complications to clinicians. And when we discussed this with patients they were most
concerned about limb amputation and possibly unclosed stomas. All of these were relatively uncommon, but we had a great collaboration with the other two ruptured aneurysm trials in Europe, AJAX and ECAR. And we put our data together.
Took 12 months, and here you can see the very consistent results. That amputations are considerably less common after endovascular repair for rupture than open repair. We've just heard about quality of life. In Improve Trial there were real gains in quality of life.
Up to three years in the endovascular strategy group. And since costs were lower, this meant that this strategy was highly cost-effective. So in summary, at three years an endovascular strategy proves to be better than open repair. With better survival, higher qualities for the patients
in the endovascular strategy group, marginally lower costs, and it's cost-effective. And we've heard quite a lot even at this meeting about our new NICE guidelines in the UK. But an endovascular strategy is actually being recommended by them for the repair of ruptures.
And I think the most cogent reasons to recommend endovascular repair are the fact that it has benefits for patients at all time points. It gives them what they want: Getting home quickly, better quality of life, lower rates of amputation and open stoma,
and better midterm survival. Thank you very much.
- Thank you so much. We have no disclosures. So I think everybody would agree that the transposed basilic vein fistula is one of the most important fistulas that we currently operate with. There are many technical considerations
related to the fistula. One is whether to do one or two stage. Your local criteria may define how you do this, but, and some may do it arbitrarily. But some people would suggest that anything less than 4 mm would be a two stage,
and any one greater than 4 mm may be a one stage. The option of harvesting can be open or endovascular. The option of gaining a suitable access site can be transposition or superficialization. And the final arterial anastomosis, if you're not superficializing can either be
a new arterial anastomosis or a venovenous anastomosis. For the purposes of this talk, transposition is the dissection, transection and re tunneling of the basilic vein to the superior aspect of the arm, either as a primary or staged procedure. Superficialization is the dissection and elevation
of the basilic vein to the superior aspect of the upper arm, which may be done primarily, but most commonly is done as a staged procedure. The natural history of basilic veins with regard to nontransposed veins is very successful. And this more recent article would suggest
as you can see from the upper bands in both grafts that either transposed or non-transposed is superior to grafts in current environment. When one looks at two-stage basilic veins, they appear to be more durable and cost-effective than one-stage procedures with significantly higher
patency rates and lower rates of failure along comparable risk stratified groups from an article from the Journal of Vascular Surgery. Meta-ana, there are several meta-analysis and this one shows that between one and two stages there is really no difference in the failure and the patency rates.
The second one would suggest there is no overall difference in maturation rate, or in postoperative complication rates. With the patency rates primary assisted or secondary comparable in the majority of the papers published. And the very last one, again based on the data from the first two, also suggests there is evidence
that two stage basilic vein fistulas have higher maturation rates compared to the single stage. But I think that's probably true if one really realizes that the first stage may eliminate a lot of the poor biology that may have interfered with the one stage. But what we're really talking about is superficialization
versus transposition, which is the most favorite method. Or is there a favorite method? The early data has always suggested that transposition was superior, both in primary and in secondary patency, compared to superficialization. However, the data is contrary, as one can see,
in this paper, which showed the reverse, which is that superficialization is much superior to transposition, and in the primary patency range quite significantly. This paper reverses that theme again. So for each year that you go to the Journal of Vascular Surgery,
one gets a different data set that comes out. The final paper that was published recently at the Eastern Vascular suggested strongly that the second stage does consume more resources, when one does transposition versus superficialization. But more interestingly also found that these patients
who had the transposition had a greater high-grade re-stenosis problem at the venovenous or the veno-arterial anastomosis. Another point that they did make was that superficialization appeared to lead to faster maturation, compared to the transposition and thus they favored
superficialization over transposition. If one was to do a very rough meta-analysis and take the range of primary patencies and accumulative patencies from those papers that compare the two techniques that I've just described. Superficialization at about 12 months
for its primary patency will run about 57% range, 50-60 and transposition 53%, with a range of 49-80. So in the range of transposition area, there is a lot of people that may not be a well matched population, which may make meta-analysis in this area somewhat questionable.
But, if you get good results, you get good results. The cumulative patency, however, comes out to be closer in both groups at 78% for superficialization and 80% for transposition. So basilic vein transposition is a successful configuration. One or two stage procedures appear
to carry equally successful outcomes when appropriate selection criteria are used and the one the surgeon is most favored to use and is comfortable with. Primary patency of superficialization despite some papers, if one looks across the entire literature is equivalent to transposition.
Cumulative patency of superficialization is equivalent to transposition. And there is, appears to be no apparent difference in complications, maturation, or access duration. Thank you so much.
- Thank you very much. I'm going to talk on Improper and Suboptimal Antiplatelet Therapy which is probably currently the standard on most carotid angioplasty stent trials and I'm going to show you how it could potentially affect all of the results we have seen so far. I have nothing to disclose.
So introduction, based on the composite end point of stroke/death in our technical trials, they're always, in all randomized trials Endarterectomy always did marginally better than Carotid angioplasty and stenting. However, a small shift, just about a one person shift
could make carotid artery stenting better could shift the results of all these carotid stent trials. Let's just look at CREST. I think it's the gold standard for randomized trial comparing endarterectomy with stenting. You can see the combined death, streak and MI rate.
For endarterectomy, it's 6.8%, for CAS, 7.2%. For stroke, again 2.3, 4.1. Again, it's a one person shift in a direction of making stents better could actually show that stents were favorable, but comparable to it, not just inferior.
Now if you look at the data on CREST, it's very interesting that the majority of the strokes, about 80% of the strokes happened after about 24 hours. In fact, most of them happened on the third day period. So it wasn't a technical issue. You know, the biggest issue with current stenting
that we find is that we have filters, we have floor reversal. They're very worried about the time we place the stent, that we balloon, pre- and post-, but it wasn't a technical issue. Something was happening after 24 hours.
Another interesting fact that no one speaks about is if you look at the CREST data a little bit in more detail, most of the mortality associated with the stenting was actually associated with an access site bleed.
So if you could really decrease the late strokes, if you can decrease the access site bleeds, I think stents can be performed better than endarterectomies. The study design for all stent trials, there was a mandatory dual antiplatelet therapy.
Almost all patients had to be on aspirin and Plavix and on CREST, interestingly, they had to be on 75 milligrams BID for Plavix so they were all on very high dose Plavix. Now here's the interesting thing about Plavix that most people don't know.
Plavix is what is called a pro-drug. It requires to be converted to its active component by the liver for antiplatelet effect. And the particular liver enzyme that converts Plavix to its active metabolic enzyme is very variable patient to patient
and you're born that way. You're either born where you can convert its active metabolite or you can't convert it to its active metabolite and a test that's called 2C19 is actually interesting approved and covered by Medicare and here's the people
that read the black box warning for Plavix, that looked at the package insert. I just cut and paste this on the package that said for Plavix. I'm just showing you a few lines from the package insert. Now next to aspirin, it's the commonest prescribed drug
by vascular specialists, but most people probably have not looked at the package insert that says effectiveness of Plavix depends on activation by a liver enzyme called 2C19 and goes on to say that tests are available to identify to 2C19 genotype.
And then they go on to actually give you a recommendation on the package insert that says consider alternative treatment strategies in patients identified as 2C19 poor metabolizers. Now these are the people who cannot metabolize Plavix and convert them to its active metabolite.
So let's look at the actual incidents. Now we know there is resistance to, in some patients, to aspirin, but the incident is so small it doesn't make worth our time or doesn't make it worth the patient's outcome to be able to test everyone for aspirin resistance,
but look at the incidents for Plavix resistance. Again, this is just a slide explaining what does resistance mean so if you're a normal metabolizer, which we hope that most of us would be, you're going to expect advocacy from Plavix at 75 milligrams once a day.
Other hand, let's say you're a rapid or ultrarapid metabolizer. You have a much higher risk of bleeding. And then if you go to the other side where you are normal, intermediate or poor metabolizer, you're not going to convert Plavix to its active metabolite
and poor metabolizers, it's like giving a placebo. And interestingly, I'm a poor metabolizer. I got myself tested. If I ever have a cardiac interventionalist give me Plavix, they're giving me a placebo. So let's look at the actual incidents
of all these subsets in patients and see whether that's going to be an issue. So we took this from about 7,000 patients and interestingly in only about 40%, NM stands for nominal metabolizer or normal metabolizers. So only 40% get the expected efficacy of Plavix.
Let's look at just the extremes. Let's just assume people with normal metabolizers, normal intermediate and the subgroup between the ultra rapid, the normals, they're all going to respond well to Plavix. Let's just look at the extremes.
Ultra rapid and poor metabolizers. So these are the people who are going to convert Plavix to a much higher concentration of its active metabolite, but have a much higher risk of bleeding. Ultra rapid metabolizers. Poor metabolizers, Plavix doesn't work.
4%, 3%. That's not a small incidence. Now in no way am I saying that carotid stent trials itselves are totally based on Plavix resistance, but just look at the data from CREST. Let's say the patients with poor metabolizers,
that's 3%, so these people did not get Plavix. Plavix does not affect you in doses of up to 600 milligram for people with poor metabolizers. Incidents of embolic events in CREST trial for carotid stents was 4%. This happened after three days.
I believe it's possibly related to platelet debris occurring in the stent on people who did not receive a liquid anti-platelet therapy. How about the people who had the groin bleed? Remember I told you that access site bleeds were most highly predictable mortality.
If you're the ultra rapid metabolizers, that incidence was 4%. So these were the people that convert Plavix with a very high dose of active metabolite, very high risk of bleeding. Access site bleed rate,
if you look at the major/minor rates, 4.1%, very close to the ultra rapid metabolizers. So fact remains that carotid angioplasty stenting post procedure events are highly dependent on appropriate antiplatelet therapy to minimize embolic events and to decrease groin bleeds.
So in conclusion, if we just included 2C19 normal metabolizers, as was recommended by the packaging insert, so just test the people, include the people on normal metabolizers, exclude the rest, we are probably going to shift the results in favor of carotid angioplasty and stenting.
Results of all carotid angioplasty stent trials need to be questioned as a significant number of patients in the carotid angioplasty stent arm did not receive appropriate antiplatelet therapy. Thank you very much.
- This is a little bit more detailed explanation of the pathophysiology behind Type IV AVM's. Medical disclosures are none. And this is the Yakes classification and this is Type IV lesion we are going to talk about now. So, this angioarchitecture has not been described before, and was first described in the Yakes classification.
What is so unique? It has multiple arteries, arterioles, but these arterioles form innumerable fistulas that are of a microsize, and they infiltrate the affected tissue. So, this is, this can affect every kind of tissue,
skin involvement and muscle involvement, and other than brain AVM, bleeding occurs if mucosa involvement is present or if an ulcer is present. So, we have to think about the definition of an AVM, which is an artery to vein connection
without an intervening capillary bed. But, what applies in Type IV? As you can see here, very nice example of this infiltrating type is that the tissue where the AVM is located is also viable, so the assumption is that
normal capillary beds are interspersed into these innumerable AVMs existing next to the malformed AVM fistulas, and this is a new definition of AVM. So, how to access this lesion? Of course, transarterial is possible
with a catheter or micro catheter. If anatomy doesn't allow transarterial approach, direct puncture is an option. Also, as you can see, in the direct puncture in the lower video, you can see the venus drainage of these fistulas,
and direct puncture of the vein compressed to reflux ethanol into the fistulas is also an approach. But, what is the challenge here? If you want to treat this lesion, you have to keep in mind
that you don't want to occlude the capillaries that are supplying the tissue. So, to find the right treatment approach, the physiologic concept is often important to understand that the arteriovenous fistulas drain into multiple veins and arterialize these veins
so we have a high pressure on this venus outflow site. The normal capillaries have a normal outflow too but this is of lower pressure, and this comes to competition between the arterialized veins and the normal venus outflow, which is, which is inferior to the normal capillary outflow.
So, what follows is a restriction of normal tissue flow with back-up to the capillaries, and backing up into the arterial inflow. So, we have the situation that the arterial venus fistulas have a lower pressure, lower resistance, and an increased arterial flow
compared to the normal capillaries, and this has to be taken into advantage for treatment. How can this be achieved? Thicken the fluid and dilute the ethanol by creating a mixture of 50/50 contrast and ethanol. So, this mixture will follow the preferential flow
into the arteriovenous fistulas in transarterial injections bearing the normal capillaries. So, if it's possible to puncture into the fistulas, pure ethanol can be used, but especially in transarterial access where normal nutrient vessels can be filled,
50:50 mixture contrast is the key to treat a Type IV AVM, Type IV Yates AVM, and here, you can see, using this approach, how this AVM can partly be treated in many several treatment sessions. And here you can see the clinical result. So, this huge ulcer, after seven treatments, healed
because of the less venus hypertension in the lesion. So the additional benefit of 50/50% ethanol contrast mixture is that your injection is visible on flouroscopy so you can see if which vessels you are including. You can react and adjust the pressure you're injecting. So, it also has to be considered
that the more you give diluted, the more total ethanol can be needed, but it's not efficient in larger vessels. This is also the advantage that you just treat the microfistulas. It's of importance that you use non-ionic contrast
as ionic contrast precipitates in the mixture. So here, you can see again, see the Type IV AVM of the arm and hand, which I already showed in my first talk, and here, you see the cured result after multiple sessions showing good arterial drum without fistulas remaining.
So, the conclusion is that Yakes Type IV is a new entity. It's crucial to understand the hemodynamics and the concept of 50/50 contrast ethanol mixture to treat this lesion with also a curative approach. Thank you very much.
- Thank you to the moderators, thank you to Dr. Veith for having me. Let's go! So my topic is to kind of introduce the ATTRACT trial, and to talk a little bit about how it affected, at least my practice, when it comes to patients with acute DVT.
I'm on the scientific advisory board for a company that makes IVC filters, and I also advise to BTG, so you guys can ask me about it later if you want. So let's talk about a case. A 50-year-old man presents
from an outside hospital to our center with left lower extremity swelling. And this is what somebody looks like upon presentation. And pulses, motor function, and sensation are actually normal at this point.
And he says to us, "Well, symptoms started "three days ago. "They're about the same since they started," despite being on anticoagulation. And he said, "Listen guys, in the other hospital, "they wouldn't do anything.
"And I want a procedure because I want the clot "out of me." so he's found to have this common femoral vein DVT. And the question is should endovascular clot removal be performed for this patient?
Well the ATTRACT trial set off to try and prevent a complication you obviously all know about, called the post-thrombotic syndrome, which is a spectrum from sort of mild discomfort and a little bit of dyspigmentation and up
to venous ulcerations and quite a lot of morbidity. And in ATTRACT, patients with proximal DVT were randomized to anticoagulation alone or in combination with pharma mechanical catheter-directed thrombolysis.
And the reason I put proximal in quotes is because it wasn't only common sort of femoral vein clots, but also femoral vein clots including the distal femoral vein were included eventually. And so patients with clots were recruited,
and as I said, they were randomized to those two treatments. And what this here shows you is the division into the two groups. Now I know this is a little small, but I'll try and kind of highlight a few things
that are relevant to this talk. So if you just read the abstract of the ATTRACT trial published last year in the New England Journal of Medicine, it'll seem to you that the study was a negative study.
The conclusion and the abstract is basically that post-thrombotic syndrome was not prevented by performing these procedures. Definitely post-thrombotic syndrome is still frequent despite treatment. But there was a signal for less severe
post-thrombotic syndrome and for more bleeding. And I was hoping to bring you all, there's an upcoming publication in circulation, hopefully it'll be online, I guess, over the weekend or early next week, talking specifically about patients
with proximal DVT. But you know, I'm speaking now without those slides. So what I can basically show you here, that at 24 months, unfortunately, there was no, well not unfortunately,
but the fact is, it did cross the significance and it was not significant from that standpoint. And what you can see here, is sort of a continuous metric of post-thrombotic syndrome. And here there was a little bit of an advantage
towards reduction of severe post-thrombotic syndrome with the procedure. What it also shows you here in this rectangle, is that were more bleeds, obviously, in the patients who received the more aggressive therapy.
One thing that people don't always talk about is that we treat our patients for two reasons, right? We want to prevent post-thrombotic syndrome but obviously, we want to help them acutely. And so what the study also showed,
was that acute symptoms resolved more quickly in patients who received the more aggressive therapy as opposed to those who did not. Again, at the price of more bleeding. So what happened to this patient? Well you know,
he presented on a Friday, obviously. So we kind of said, "Yeah, we probably are able "to try and do something for you, "but let's wait until Monday." And by Monday, his leg looked like this, with sort of a little bit of bedrest
and continued anticoagulation. So at the end of the day, no procedure was done for this particular patient. What are my take home messages, for whatever that's worth? Well I think intervention for DVT
has several acute indications. Restore arterial flow when phlegmasia is the problem, and reduce acute symptoms. I think intervention for common femoral and more proximal DVT likely does have long-term benefit, and again, just be
on the lookout for that circ paper that's coming out. Intervention for femoral DVT, so more distal DVT, in my opinion, is rarely indicated. And in the absence of phlegmasia, for me, thigh swelling is a good marker for a need
for a procedure, and I owe Dr. Bob Schainfeld that little tidbit. So thank you very much for listening.
- So I'm just going to talk a little bit about what's new in our practice with regard to first rib resection. In particular, we've instituted the use of a 30 degree laparoscopic camera at times to better visualize the structures. I will give you a little bit of a update
about our results and then I'll address very briefly some controversies. Dr. Gelbart and Chan from Hong Kong and UCLA have proposed and popularized the use of a 30 degree laparoscopic camera for a better visualization of the structures
and I'll show you some of those pictures. From 2007 on, we've done 125 of these procedures. We always do venography first including intervascular intervention to open up the vein, and then a transaxillary first rib resection, and only do post-operative venography if the vein reclots.
So this is a 19 year old woman who's case I'm going to use to illustrate our approach. She developed acute onset left arm swelling, duplex and venogram demonstrated a collusion of the subclavian axillary veins. Percutaneous mechanical thrombectomy
and then balloon angioplasty were performed with persistent narrowing at the thoracic outlet. So a day later, she was taken to the operating room, a small incision made in the axilla, we air interiorly to avoid injury to the long thoracic nerve.
As soon as you dissect down to the chest wall, you can identify and protect the vein very easily. I start with electrocautery on the peripheral margin of the rib, and use that to start both digital and Matson elevator dissection of the periosteum pleura
off the first rib, and then get around the anterior scalene muscle under direct visualization with a right angle and you can see that the vein and the artery are identified and easily protected. Here's the 30 degree laparoscopic image
of getting around the anterior scalene muscle and performing the electrocautery and you can see the pulsatile vein up here anterior and superficial to the anterior scalene muscle. Here is a right angle around the first rib to make sure there are no structures
including the pleura still attached to it. I always divide, or try to divide, the posterior aspect of the rib first because I feel like then I can manipulate the ribs superiorly and inferiorly, and get the rib shears more anterior for the anterior cut
because that's most important for decompressing the vein. Again, here's the 30 degree laparoscopic view of the rib shears performing first the posterior cut, there and then the anterior cut here. The portion of rib is removed, and you can see both the artery and the vein
are identified and you can confirm that their decompressed. We insufflate with water or saline, and then perform valsalva to make sure that they're hasn't been any pneumothorax, and then after putting a drain in,
I actually also turn the patient supine before extirpating them to make sure that there isn't a pneumothorax on chest x-ray. You can see the Jackson-Pratt drain in the left axilla. One month later, duplex shows a patent vein. So we've had pretty good success with this approach.
23 patients have requires post operative reintervention, but no operative venous reconstruction or bypass has been performed, and 123 out of 125 axillosubclavian veins have been patent by duplex at last follow-up. A brief comment on controversies,
first of all, the surgical approach we continue to believe that a transaxillary approach is cosmetically preferable and just as effective as a paraclavicular or anterior approach, and we have started being more cautious
about postoperative anticoagulation. So we've had three patients in that series that had to go back to the operating room for washout of hematoma, one patient who actually needed a VATS to treat a hemathorax,
and so in recent times we've been more cautious. In fact 39 patients have been discharged only with oral antiplatelet therapy without any plan for definitive therapeutic anticoagulation and those patients have all done very well. Obviously that's contraindicated in some cases
of a preoperative PE, or hematology insistence, or documented hypercoagulability and we've also kind of included that, the incidence of postop thrombosis of the vein requiring reintervention, but a lot of patients we think can be discharged
on just antiplatelets. So again, our approach to this is a transaxillary first rib resection after a venogram and a vascular intervention. We think this cosmetically advantageous. Surgical venous reconstruction has not been required
in any case, and we've incorporated the use of a 30 degree laparoscopic camera for better intraoperative visualization, thanks.
- I'm going to be speaking about indirect access sites for access intervention. I'm going to be focusing on the transjugular approach. So access interventions, typically we perform them through a direct puncture of the fistula. Sometimes you place two introducers. There are some disadvantages to the direct approach.
The crossing catheters technique that we generally use for declots is awkward and cumbersome. The introducers can obstruct flow, there's dead space behind the introducers that can trap clot, and there's radiation exposure or the direct exposure
or scatter radiation from hands near the field. Admit it, we've all had access-site complications, suture-site necrosis and infection, as well as pseudoaneurysms. There's also prolonged procedure time related to needing to obtain hemostasis
in the high-pressure segment. There are also problems particularly to immature fistulas, such as hematoma formation, spasm at the introducer site causing pseudo-stenosis, decreased flow, and fistula thrombosis. Now, the good news is that we do have options
for alternative access sites. I'm sure many of you here use arterial access for immature fistulas in particular. Brachial access can be used to, this can be used for diagnostic or therapeutic purposes. We can also utilize radial or ulnar access.
Rarely, femoral access is used, as we saw in the last presentation. But there's also pendula venous access sites. You can sometimes, as a fortuitous tributary, what I call a target of opportunity, and also, the internal jugular vein.
Now, the transjugular approach was first reported in 1998. It does have some definite advantages over direct puncture technique. You can avoid the cumbersome access, you can keep your hands away from the beam, and there's no dead space as compared
to crossing sheaths for your declot. And if the intervention is unsuccessful, you can convert your IJ access to a catheter if you already have a wire in it. There are some technical challenges associated with this technique.
You do have to overcome the valves. It can be difficult to access the cephalic vein, but you can get around this by using a snare. And there's possibly a risk of IJ thrombosis if you're using large introducers. When to use this technique?
Well, when direct puncture's going to be difficult or cumbersome, when there's a short cannulation segment, when it's an extensively stented access, and when there's inflow pathology requiring a retrograde approach or arterial empathalogy, and it's a good option for clotted access.
The technique, micropuncture access of the jugular vein, ipsilateral or contralateral, place a sheath, and an important thing to use is a reverse-curve catheter, followed by glidewire. So here, we've cannulated the jugular vein going down,
glidewire out into the arm. If you're unable to cross into the cephalic vein, you can use that snare technique. And you can get a long, stable access in this way. It's been reported about, there's about 10 publications on transjugular approach, seven retrospective studies.
There's a large study that's reported thrombectomy. Also a large study looking at immature fistulas. Smaller studies looking at dysfunctional access and pseudoaneurysms. Two case reports, one review article, but there's of course no randomized studies.
There's a recent study from this year from Ferral and Alonzo. This was a retrospective study. Over two years they performed 30 transjugular AV access interventions. This accounted for 5% of their access experience
and this series was all fistulance. Indications for the procedure, 43% were declots, 43% were arterial and fistual pathology, there were two immature fistulas and two bleeding pseudoaneurysms. The access approach was 29 for ipsilateral,
only one contralateral. The results, 97% technical success, a snare was required in 4 cases, a catheter was inserted in two of the cases. There were no episodes of jugular vein thrombosis. In the remaining time, I'd like to show
a couple of case studies. Again, from Ferral and Alonzo. This is a case of an immature fistula. This was a partially occluded, immature left upper arm fistula. The initial fistulagram shows outflow stenosis
with a multiple stenosis in thrombus, and there's an arterial in stenosis that's distal to the access point, so you're not going to be able to treat that. They performed four millimeter angioplasty. Follow-up fistulagram shows a small, but patent vein
and the arterial end could not be treated. They brought the patient back in two weeks for a staged transjugular approach. And you can see the jugular catheter coming down. The vein diameter's improved, but there's still the untreated arterial end stenosis,
which is easily treated through the jugular approach. This is a study from, a case from Dr. Rabellino, ruptured pseudoaneurysm. This is a basilic transposition with a ruptured pseudoaneurysm at an infiltration site. Pretty ugly arm, swollen, skin necrosis.
I don't think we want to be sticking that arm. They initially went with a femoral approach for the fistulagram, demonstrated the pseudoaneurysm. As you can see here, tandem outflow stenoses. Coming up from below with the femoral artery diagnostic catheter.
Down and into the arm through the jugular approach. And here, you can see the venous outflow after angioplasty, covered stent deployed through the jugular access. So in summary, the transjugular approach is a useful but underutilized technique. The advantages include single-puncture intervention,
does not involve the outflow vein directly, simplified hemostasis, it's a low pressure system. It does have the advantage that you can use large introducers, there's less radiation for the operator, and you can convert to a catheter easily if needed. It is a useful technique for fistula maturation,
thrombectomy, and access maintenance. I say go for the jugular.
- Ladies and gentlemen, I thank Frank Veith and the organizing committee for the invitation. I have no disclosures for this presentation. Dialysis is the life line of patients with end-stage renal failure. Hemodialysis can be done by constructing an A-V fistula, utilizing a graft or through a central venous catheter.
Controversy as to the location of A-V fistula, size of adequate vein and priority of A-V fistula versus A-V graft exists among different societies. Our aims were to present our single center experience with A-V fistulas and grafts. Compare their patency rates,
compare different surgical sites, and come up with preferences to allow better and longer utilization. We collected all patients who underwent A-V fistula or A-V graft between the years 2008 through 2014. We included all patients who had preoperative
duplex scanning or those deemed to have good vessels on clinical examination. Arteries larger than two point five millimeter and veins larger than three millimeter were considered fit. Dialysis was performed three times per week. Follow up included check for a thrill,
distal pulse in the arter non-increased venous pressure or visible effective dialysis and no prolonged bleeding. Any change of one of the above would led to obtaining
fistulogram resulting in either endovascular or open repair of the fistula. We started with 503 patients, 32 of which were excluded due to primary failure within 24 hours. We considered this, of course, the surgeon's blame. So we left with 471 patients with a mean age of 58 years,
51 were older than 60, there was a male predominance of 63%, and over half were diabetics. The type of fistula was 41% brachio-cephalic fistula, 30% radio-cephalic fistula, 16% A-V Graft, and 13% brachio-basilic fistula.
Overall, we had 84% fistulas and 16% grafts. The time to first dialysis and maturation of fistula was approximately six weeks. First use of grafts was after two weeks. 11 patients with A-V fistula needed early intervention prior to or after the first dialysis session.
In sharp contrast, none of the A-V grafts needed early intervention. 68 patients were operated for their first ever fistula without duplex scanning due to clinically good vessels. Their patency was comparable to those who underwent a preoperative scanning.
Looking at complications, A-V grafts needed more reintervention than fistulas. All of them were late. Infection was more prominent in the graft group and pseudoaneurysms were more prominent in the A-V fistula group, some of them occluded
or invaded the skin and resulted in bleeding. Here's a central vein occlusion and you can see this lady is after a brachio-basilic A-V shunt. You can see the swollen arm, the collaterals. Here are multiple venous aneurysms. Here's an ulcer.
When we looked at primary patency of A-V fistulas versus graft, A-V fistulas fared better than grafts for as long as five years. When you looked at 50% patency in grafts, it was approximately 18 months, in Fistula, 13. Here's an assisted primary patency by endovascular technique
and when we looked at the secondary patency for the first 24, two years, months, there was no difference between A-V fistulas and A-V grafts, but there's a large difference afterwards. Comparing radio-cephalic fistula to brachio-cephalic fistula there was really no big difference in maturation.
The time was approximately six weeks. As for primary patency there is a trend towards better patency with brachio-cephalic fistula after six months, one year, and two years, but it didn't reach statistical significance. For patients with diabetes,
differences were statistically significant. Brachio-cephalic fistula showed a trend toward shorter maturation time, needed less reintervention, and had a longer patency rate. In conclusions then, ladies and gentlemen, A-V fistula require a longer maturation time
and have higher pseudoaneurysm formation rate, but better patency rates compared to A-V grafts. A-V grafts have a faster maturation time, but more late interventions are required and infection is more common. Finally, diabetic patients have a better result
with proximal A-V fistulas. Thank you for the opportunity to present our data.
- Thank you (mumbles). The purpose of deep venous valve repair is to correct the reflux. And we have different type of reflux. We know we have primary, secondary, the much more frequent and the rear valve agenesia. In primary deep venous incompetence,
valves are usually present but they are malfunctioning and the internal valvuloplasty is undoubtedly the best option. If we have a valve we can repair it and the results are undoubtedly the better of all deep vein surgery reconstruction
but when we are in the congenital absence of valve which is probably the worst situation or we are in post-thrombotic syndrome where cusps are fully destroyed, the situation is totally different. In this situation, we need alternative technique
to provide a reflux correction that may be transposition, new valve or valve transplants. The mono cuspid valve is an option between those and we can obtain it by parietal dissection. We use the fibrotic tissue determined by the
sickening of the PTS event obtaining a kind of flap that we call valve but as you can realize is absolutely something different from a native valve. The morphology may change depending on the wall feature and the wall thickness
but we have to manage the failure of the mono cuspid valve which is mainly due to the readhesion of the flap which is caused by the fact that if we have only a mono cuspid valve, we need a deeper pocket to reach the contralateral wall so bicuspid valve we have
smaller cusps in mono cuspid we have a larger one. And how can we prevent readhesion? In our first moment we can apply a technical element which is to stabilize the valve in the semi-open position in order not to have the collapse of the valve with itself and then we had decide to apply an hemodynamic element.
Whenever possible, the valve is created in front of a vein confluence. In this way we can obtain a kind of competing flow, a better washout and a more mobile flap. This is undoubtedly a situation that is not present in nature but helps in providing non-collapse
and non-thrombotic events in the cusp itself. In fact, if we look at the mathematical modeling in the flow on valve you can see how it does work in a bicuspid but when we are in a mono cuspid, you see that in the bottom of the flap
we have no flow and here there is the risk of thrombosis and here there is the risk of collapse. If we go to a competing flow pattern, the flap is washed out alternatively from one side to the other side and this suggest us the idea to go through a mono cuspid
valve which is not just opens forward during but is endovascular and in fact that's what we are working on. Undoubtedly open surgery at the present is the only available solution but we realized that obviously to have the possibility
to have an endovascular approach may be totally different. As you can understand we move out from the concept to mimic nature. We are not able to provide the same anatomy, the same structure of a valve and we have to put
in the field the possibility to have no thrombosis and much more mobile flap. This is the lesson we learn from many years of surgery. The problem is the mobile flap and the thrombosis inside the flap itself. The final result of a valve reconstruction
disregarding the type of method we apply is to obtain an anti-reflux mechanism. It is not a valve, it is just an anti-reflux mechanism but it can be a great opportunity for patient presenting a deep vein reflux that strongly affected their quality of life.
- Thank you very much Tony, It's an honor to be part of this distinguished faculty. This is a landmark paper that truly revolutionized the management of Iliac vein disease, and you can see in this great experience of Doctor Raju and Neglen,
that primary disease, May-Thurner syndrome, can be treated with a secondary patency of 100% at five years and even in post traumatic patients, the secondary patency rate in this series was 86%. Now it was not immediately recognized that Contralateral Deep Vein Thrombosis is a problem.
In this paper, the authors mentioned that Contralateral Iliac Vein Thrombosis was generally benign and infrequent, 1%. The same group however with increasing experience recognized that some patients, who undergo Iliac Vein stenting have a problem if the stent is extended into the iliac vein.
And they did a comparative series where one group included wallstents that were extended into the inferior vena cava because of the underlying anatomy to correctly treat the disease. And the control group had Z-Stent on top of the wallstent which as you could see in the previous presentation
has much larger gaps between the metal struts. Wallstent in critical areas like under the compression of the right common iliac artery or even the groin can be compressed because of the construction of the stent. And you can see that there was a significant difference from Ipsilateral Deep Vein Thrombosis
if you used a stronger Z-Stent than if you used just a wall stent. But obviously the important finding is that there was a significantly higher rate of Contralateral Deep Vein Thrombosis if you extended the wall stent without protection
of the Z-Stent. Now there are additional papers that have come out since this publication. This is a combined European experience that, oh no actually, this is just the conclusion of the study that obviously
the Z-Stent modifications provides protection. But this is the European experience that only show that 4% had identified multiple factors in addition to extension like Acute disease, previous Contralateral Deep Vein Thrombosis or non-compliance with anticoagulation.
This paper however didn't really differentiate between extension and coverage, complete coverage of the Contralateral outflow. This is another paper from Dr. Gillespie group that again, thought that those patients who were non-compliant with anticoagulation,
those had an increased risk of Contralateral Deep Vein Thrombosis. Now this is a very important paper. It's 111 patients that was just recently published in the Jvir What is interesting in this patient
that Contralateral Deep Vein Thrombosis developed in 10 patients at a median time of 40 month after the operation. And I think that's very important. That this is not an early complication. This is a late complication.
And it's obvious from their findings, that you may not find a significant difference as long as you partially cover the iliac vein. But if you completely cover the iliac vein, 32% of these patients had Contralateral Deep Vein Thrombosis with a significant difference.
We found that in our experience too that when we explanted a stent that the outflow was practically already halfway thrombosed and you can see the pseudointima that really depends on the poor size of the stent. And that's why actually any stent
that has this small size has a problem. And so we called to abandon on extending the wallstent into the inferior vena cava. I think the take home message now that you should remember is that overextension of the iliac vein stent into the IVC and completely covering the inflow
from the Contralateral Iliac Vein is obviously a clear and present danger of delayed, not early, delayed Contralateral Deep Vein Thrombosis. Thank you.
- So my charge is to talk about using band for steal. I have no relevant disclosures. We're all familiar with steal. The upper extremity particularly is able to accommodate for the short circuit that a access is with up to a 20 fold increase in flow. The problem is that the distal bed
is not necessarily as able to accommodate for that and that's where steal comes in. 10 to 20% of patients have some degree of steal if you ask them carefully. About 4% have it bad enough to require an intervention. Dialysis associated steal syndrome
is more prevalent in diabetics, connective tissue disease patients, patients with PVD, small vessels particularly, and females seem to be predisposed to this. The distal brachial artery as the inflow source seems to be the highest risk location. You see steal more commonly early with graft placement
and later with fistulas, and finally if you get it on one side you're very likely to get it on the other side. The symptoms that we are looking for are coldness, numbness, pain, at the hand, the digital level particularly, weakness in hand claudication, digital ulceration, and then finally gangrene in advanced cases.
So when you have this kind of a picture it's not too subtle. You know what's going on. However, it is difficult sometimes to differentiate steal from neuropathy and there is some interaction between the two.
We look for a relationship to blood pressure. If people get symptomatic when their blood pressure's low or when they're on the access circuit, that is more with steal. If it's following a dermatomal pattern that may be a median neuropathy
which we find to be pretty common in these patients. Diagnostic tests, digital pressures and pulse volume recordings are probably the best we have to assess this. Unfortunately the digital pressures are not, they're very sensitive but not very specific. There are a lot of patients with low digital pressures
that have no symptoms, and we think that a pressure less than 60 is probably consistent, or a digital brachial index of somewhere between .45 and .6. But again, specificity is poor. We think the digital pulse volume recordings is probably the most useful.
As you can see in this patient there's quite a difference in digital waveforms from one side to the other, and more importantly we like to see augmentation of that waveform with fistula compression not only diagnostically but also that is predictive of the benefit you'll get with treatment.
So what are our treatment options? Well, we have ligation. We have banding. We have the distal revascularization interval ligation, or DRIL, procedure. We have RUDI, revision using distal inflow,
and we have proximalization of arterial inflow as the approaches that have been used. Ligation is a, basically it restores baseline anatomy. It's a very simple procedure, but of course it abandons the access and many of these patients don't have a lot of good alternatives.
So it's not a great choice, but sometimes a necessary choice. This picture shows banding as we perform it, usually narrowing the anastomosis near the artery. It restricts flow so you preserve the fistula but with lower flows.
It's also simple and not very morbid to do. It's got a less predictable effect. This is a dynamic process, and so knowing exactly how tightly to band this and whether that's going to be enough is not always clear. This is not a good choice for low flow fistula,
'cause again, you are restricting flow. For the same reason, it's probably not a great choice for prosthetic fistulas which require more flow. So, the DRIL procedure most people are familiar with. It involves a proximalization of your inflow to five to 10 centimeters above the fistula
and then ligation of the artery just below and this has grown in popularity certainly over the last 10 or 15 years as the go to procedure. Because there is no flow restriction with this you don't sacrifice patency of the access for it. It does add additional distal flow to the extremity.
It's definitely a more morbid procedure. It involves generally harvesting the saphenous vein from patients that may not be the best risk surgical patients, but again, it's a good choice for low flow fistula. RUDI, revision using distal inflow, is basically
a flow restrictive procedure just like banding. You're simply, it's a little bit more complicated 'cause you're usually doing a vein graft from the radial artery to the fistula. But it's less complicated than DRIL. Similar limitations to banding.
Very limited clinical data. There's really just a few series of fewer than a dozen patients each to go by. Finally, a proximalization of arterial inflow, in this case rather than ligating the brachial artery you're ligating the fistula and going to a more proximal
vessel that often will accommodate higher flow. In our hands, we were often talking about going to the infraclavicular axillary artery. So, it's definitely more morbid than a banding would be. This is a better choice though for prosthetic grafts that, where you want to preserve flow.
Again, data on this is very limited as well. The (mumbles) a couple years ago they asked the audience what they like and clearly DRIL has become the most popular choice at 60%, but about 20% of people were still going to banding, and so my charge was to say when is banding
the right way to go. Again, it's effect is less predictable than DRIL. You definitely are going to slow the flows down, but remember with DRIL you are making the limb dependent on the patency of that graft which is always something of concern in somebody
who you have caused an ischemic hand in the first place, and again, the morbidity with the DRIL certainly more so than with the band. We looked at our results a few years back and we identified 31 patients who had steal. Most of these, they all had a physiologic test
confirming the diagnosis. All had some degree of pain or numbness. Only three of these patients had gangrene or ulcers. So, a relatively small cohort of limb, of advanced steal. Most of our patients were autogenous access,
so ciminos and brachycephalic fistula, but there was a little bit of everything mixed in there. The mean age was 66. 80% were diabetic. Patients had their access in for about four and a half months on average at the time of treatment,
although about almost 40% were treated within three weeks of access placement. This is how we do the banding. We basically expose the arterial anastomosis and apply wet clips trying to get a diameter that is less than the brachial artery.
It's got to be smaller than the brachial artery to do anything, and we monitor either pulse volume recordings of the digits or doppler flow at the palm or arch and basically apply these clips along the length and restricting more and more until we get
a satisfactory signal or waveform. Once we've accomplished that, we then are satisfied with the degree of narrowing, we then put some mattress sutures in because these clips will fall off, and fix it in place.
And basically this is the result you get. You go from a fistula that has no flow restriction to one that has restriction as seen there. What were our results? Well, at follow up that was about almost 16 months we found 29 of the 31 patients had improvement,
immediate improvement. The two failures, one was ligated about 12 days later and another one underwent a DRIL a few months later. We had four occlusions in these patients over one to 18 months. Two of these were salvaged with other procedures.
We only had two late recurrences of steal in these patients and one of these was, recurred when he was sent to a radiologist and underwent a balloon angioplasty of the banding. And we had no other morbidity. So this is really a very simple procedure.
So, this is how it compares with DRIL. Most of the pooled data shows that DRIL is effective in 90 plus percent of the patients. Patency also in the 80 to 90% range. The DRIL is better for late, or more often used in late patients,
and banding used more in earlier patients. There's a bigger blood pressure change with DRIL than with banding. So you definitely get more bang for the buck with that. Just quickly going through the literature again. Ellen Dillava's group has published on this.
DRIL definitely is more accepted. These patients have very high mortality. At two years 50% are going to be dead. So you have to keep in mind that when you're deciding what to do. So, I choose banding when there's no gangrene,
when there's moderate not severe pain, and in patients with high morbidity. As promised here's an algorithm that's a little complicated looking, but that's what we go by. Again, thanks very much.
- So this was born out of the idea that there were some patients who come to us with a positive physical exam or problems on dialysis, bleeding after dialysis, high pressures, low flows, that still have normal fistulograms. And as our nephrology colleagues teach us, each time you give a patient some contrast,
you lose some renal function that they maintain, even those patients who are on dialysis have some renal function. And constantly giving them contrasts is generally not a good thing. So we all know that intimal hyperplasia
is the Achilles Heel of dialysis access. We try to do surveillance. Debbie talked about the one minute check and how effective dialysis is. Has good sensitivity on good specificity, but poor sensitivity in determining
dialysis access problems. There are other measured parameters that we can use which have good specificity and a little better sensitivity. But what about ultrasound? What about using ultrasound as a surveillance tool and how do you use it?
Well the DOQI guidelines, the first ones, not the ones that are coming out, I guess, talked about different ways to assess dialysis access. And one of the ways, obviously, was using duplex ultrasound. Access flows that are less than 600
or if they're high flows with greater than 20% decrease, those are things that should stimulate a further look for clinical stenosis. Even the IACAVAL recommendations do, indeed, talk about volume flow and looking at volume flow. So is it volume flow?
Or is it velocity that we want to look at? And in our hands, it's been a very, very challenging subject and those of you who are involved with Vasculef probably have the same thing. Medicare has determined that dialysis shouldn't, dialysis access should not be surveilled with ultrasound.
It's not medically necessary unless you have a specific reason for looking at the dialysis access, you can't simply surveil as much as you do a bypass graft despite the work that's been done with bypass graft showing how intervening on a failing graft
is better than a failed graft. There was a good meta-analysis done a few years ago looking at all these different studies that have come out, looking at velocity versus volume. And in that study, their conclusion, unfortunately, is that it's really difficult to tell you
what you should use as volume versus velocity. The problem with it is this. And it becomes, and I'll show you towards the end, is a simple math problem that calculating volume flows is simply a product of area and velocity. In terms of area, you have to measure the luminal diameter,
and then you take the luminal diameter, and you calculate the area. Well area, we all remember, is pi r squared. So you now divide the diameter in half and then you square it. So I don't know about you,
but whenever I measure something on the ultrasound machine, you know, I could be off by half a millimeter, or even a millimeter. Well when you're talking about a four, five millimeter vessel, that's 10, 20% difference.
Now you square that and you've got a big difference. So it's important to use the longitudinal view when you're measuring diameter. Always measure it if you can. It peaks distally, and obviously try to measure it in an non-aneurysmal area.
Well, you know, I'm sure your patients are the same as mine. This is what some of our patients look like. Not many, but this is kind of an exaggerated point to make the point. There's tortuosity, there's aneurysms,
and the vein diameter varies along the length of the access that presents challenges. Well what about velocity? Well, I think most of us realize that a velocity between 100 to 300 is probably normal. A velocity that's over 500, in this case is about 600,
is probably abnormal, and probably represents a stenosis, right? Well, wait a minute, not necessarily. You have to look at the fluid dynamic model of this, and look at what we're actually looking at. This flow is very different.
This is not like any, not like a bypass graft. You've got flow taking a 180 degree turn at the anastomosis. Isn't that going to give you increased turbulence? Isn't that going to change your velocity? Some of the flow dynamic principles that are important
to understand when looking at this is that the difference between plug and laminar flow. Plug flow is where every bit is moving at the same velocity, the same point from top to bottom. But we know that's not true. We know that within vessels, for the most part,
we have laminar flow. So flow along the walls tends to be a little bit less than flow in the middle. That presents a problem for us. And then when you get into the aneurysmal section, and you've got turbulent flow,
then all bets are off there. So it's important, when you take your sample volume, you take it across the whole vessel. And then you get into something called the Time-Averaged mean velocity which is a term that's used in the ultrasound literature.
But it basically talks about making sure that your sample volume is as wide as it can be. You have to make sure that your angle is as normal in 60 degrees because once you get above 60 degrees, you start to throw it off.
So again, you've now got angulation of the anastomosis and then the compliance of a vein and a graft differs from the artery. So we use the two, we multiply it, and we come up with the volume flow. Well, people have said you should use a straight segment
of the graft to measure that. Five centimeters away from the anastomosis, or any major branches. Some people have actually suggested just using a brachial artery to assess that. Well the problems in dialysis access
is there are branches and bifurcations, pseudoaneurysms, occlusions, et cetera. I don't know about you, but if I have a AV graft, I can measure the volume flow at different points in the graft to get different numbers. How is that possible?
Absolutely not possible. You've got a tube with no branches that should be the same at the beginning and the end of the graft. But again, it becomes a simple math problem. The area that you're calculating is half the diameter squared.
So there's definitely measurement area with the electronic calipers. The velocity, you've got sampling error, you've got the anatomy, which distorts velocity, and then you've got the angle with which it is taken. So when you start multiplying all this,
you've got a big reason for variations in flow. We looked at 82 patients in our study. We double blinded it. We used a fistulagram as the gold standard. The duplex flow was calculated at three different spots. Duplex velocity at five different spots.
And then the diameters and aneurysmal areas were noted. This is the data. And basically, what it showed, was something totally non-significant. We really couldn't say anything about it. It was a trend toward lower flows,
how the gradients (mumbles) anastomosis, but nothing we could say. So as you all know, you can't really prove the null hypothesis. I'm not here to tell you to use one or use the other, I don't think that volume flow is something that
we can use as a predictor of success or failure, really. So in conclusion, what we found, is that Debbie Brow is right. Clinical examinations probably still the best technique. Look for abnormalities on dialysis. What's the use of duplex ultrasound in dialysis or patients?
And I think we're going to hear that in the next speaker. But probably good for vein mapping. Definitely good for vein mapping, arterial inflow, and maybe predicting maturation. Thank you very much.
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