[MUSIC PLAYING]

MARIA VEGA: Hi, thank you, everyone, for joining us this evening. My name is Maria Vega. I am the senior product manager for the Venovo Venous Stent System. This evening, Dr. Paul Gagne you will be presenting on his experience using Venovo's stent, and on how he can optimize venous stenting outcomes.

But before we get started. Here's a brief introduction on our presenter. Dr. Paul Gagne is a world renowned vascular surgeon who specializes in vascular and endovascular techniques for the treatment of arterial and venous disease. He joined the Vascular Experts in 2007, is the president of the Vascular Health Forum, and is a distinguished member of the Society of Vascular Surgery and of the American Venous Forum.

Dr. Gagne also served in the US Navy as both general and vascular surgeon. His research focuses on deep vein system. And he was part of Venovo Stent VERNACULAR clinical trial, which allowed him to gain significant insight and knowledge into the Venovo Venous Stent. And since FDA approval in March of 2019, he has had extensive experience using the Venovo Stent.

With that said, I would like to invite Dr. Gagne to present on his experience using Venovo on how to optimize venous stenting outcomes. Also, please do not hesitate to ask questions in the chat box below the screen and use the adjacent polling tool to submit your answers during the polling questions throughout the presentation.

So with that said, Dr. Gagne?

DR PAUL GAGNE: Thank you, Maria. It's a real pleasure to participate in this webcast tonight. The world of deep venous disease and treatment for those who are suffering from the worst of chronic venous hypertension, it has made big leaps in the last decade in the treatment of venous outflow obstruction.

And now that we have great new tools such as the Venovo Stent available to us commercially, it makes our life better. And it gives us better outcomes for our patients. So tonight we'll talk about the stent study that was published and its two year outcome data. And we'll also talk about some of the tips and tricks that I think of as I'm undertaking the treatment of these patients.

So we'll go ahead and share my slides. Share the screen. And I think we're a go.

All right. So the Venovo Venous Stent was approved as Maria said in March of last year for the treatment of symptomatic iliofemoral vein outflow tract obstruction. It's a self-expanding nitinol stent specifically designed for the deep veins. It has flared ends designed to ensure that there's good wall apposition between the stent and the vein to prevent migration. There's a tri-axial delivery system and a copious amount of markers so that the stent is easily seen.

It comes in a broad range of diameters, 10 to 20 millimeters in two-millimeter increments. And it goes from 40 to 160 millimeters long. And it is deployed in an eight through 10 French system.

The VERNACULAR study was the Pivotal IDE Study that led to commercialization. The objective of the study was to assess the performance of the stent for iliac and common femoral vein outflow tract obstruction treatment. It was a prospective, multi-center study, non-randomized single arm. 170 patients at 21 sites around the world were enrolled. And there was independent analysis on the venograms with core lab evaluation of the venograms and radiological imaging to look for problems such as stent fracture, and also on the duplex ultrasound imaging used in pre and post-op evaluation.

The inclusion and exclusion criteria are as shown. Inclusion was unilateral, common femoral common or external iliac vein disease. The patients had to be symptomatic, and therefore had to have at least C3 clinical disease, or edema, and a VCSS pain score greater than 2. And a greater than 50% diameter reduction by venography was the bar for inclusion radiographically.

The reference vessel diameter had to be between 7 millimeters and 19 millimeters so that the stent was used within its IFU.

The exclusion criteria was by bilateral disease, or uncorrectable bleeding diathesis, prior stents in the targeted vessel, or any ability to cross the total occlusion. You can see here that the mean age was 52. There were slightly more women than men in a 2 to 1 ratio. And if you look at the types of lesions that were treated, about a little less than half had post-thrombotic syndrome. And the rest were NIVL or compression lesions.

And you can see that there was a lot more men represented in the PTS group than in the NIVL group. And then if you look at the lesion types that were treated, the common iliac vein was most commonly treated, followed closely thereafter by the external iliac vein, and then the common femoral vein. And if you look at the PTS group, the common femoral vein was much more commonly treated due to the nature of these lesions, which are much more lengthy than as a NIVL lesion, where it was rarer that the common femoral vein had to be stented.

If you look at the mean lesion length, it was 80 millimeters in the PTS group versus 55 millimeters in the compression group, not surprising. Thrombus presence was more common in the post-thrombotic group than in the compression group, again not surprising. And then finally the mean stented length was longer at just over 10 centimeters in the PTS group versus the compression or NIVL group. But it's important to note here that in general in the venous system, we use long stents.

If you look at the 24 month outcome data, you can see that the primary patency was excellent. At 24 months, you have 83% patency as an aggregate. There have been no stent fractures noted within this IDE trial. If you look at the patency rates for the post-thrombotic group versus the compression group, again, consistent with the literature experience in this field. There was 73% patency at 24 months, which is quite robust. And 95% patency in the compression group.

So again, both groups doing quite well as far as primary patency.

Now the Arnsberg Registry was another data set on the Venovo Venous Stent. And this is a real world study. It's a registry that Dr. Lichtenberg and Dr. de Graaf have been maintaining. And they looked at primary patency at 12 months with clinical outcomes at 12 months in patients that they treated who had iliac and common femoral, both post-thrombotic and non-thrombotic disease in their clinic and using the Venovo Stent.

And what they found was that they've used CEAP 3, 4, 5, and 6 patients. About half their patients were the more severe CEAP 4 through 6. And 20% of these were extending from the common femoral vein up through the common iliac vein. Another 10% under the inguinal ligament to the common femoral vein on the left, and then about 15% on the right. So a large group under the inguinal ligament.

And what you see here is they had excellent primary patency for all patients at 12 months. They had primary patency that was 96%, and it was not much different for compression lesions versus post-thrombotic diseases. So in the hands of very experienced investigators, you can see excellent long term results irrelevant of the lesion type using this stent.

So in conclusion, the IDE trial, the VERNACULAR study, showed excellent primary patency of 84% with zero stent fractures. And improvement in the VCSS pain score and the CIVIQ quality of life score, which were the two clinical parameters that were tracked. And then mirroring this is the results from the Arnsberg Registry, showing significant VCSS improvement in over half the patients. And the CEAP score is decreasing on average from 4.3 down to 2.7 after treatment.

So how do you get these excellent outcomes with the patients who present with some complicated problems using the new technology that we now have available? Well the first question, is when to stent. And we have a question.

MARIA VEGA: We are going to go to question number one. So on your chat box, a question will pop up. And the first question is, what clinical CEAP categories have the best clinical response to iliofemoral vein IVIS imaging and stenting of a 50% cross section area reduction? You'll see the options there on your screen. Please go ahead and start clicking your answers. We'll give you about 30 seconds.

And I think for now we can, while people put in the answers, we can move on to the next slide.

DR PAUL GAGNE: So, this is what I call my persons of interest slide. These are the patients that I think about when I'm focusing on patients who are most likely to have iliofemoral outflow obstruction that would be amenable to balloon angioplasty and stent treatment.

If you look on the left, you can see this patient has unilateral swelling and hyper pigmentation in his leg with some erosions on the back of the ankle. You see in the middle picture, swelling that induration of the skin and stasis dermatitis. And even though it's bilateral, the feet are spared, and these patients often-time have iliac vein outflow obstruction. And then you can see in the right panel, the patient who has skin damage starting to wrap around the leg. It's not just focal to the medial balalus, even though the ulcer is present.

And so patients that have skin damage wrapping around the leg with or without an active or healed ulcer, if you've treated other superficial disease, and they've still got skin damage, skin induration, inflammation, they probably have some outflow obstruction.

MARIA VEGA: Dr. Gagne, we got the answers for the first question. What clinical CEAP categories have the best clinical response to iliofemoral vein IVIS imaging and stenting of a 50% cross-section area reduction? The majority of the people answered C, CEAP 4, 5, 6, with 52%. And then the second answer was D, CEAP 3, 4, 5, with 31%. What do you think about those results?

DR PAUL GAGNE: Well, I favor the answer. I think the patients who have an active ulcer or a healed ulcer-- the patients who have a healed ulcer oftentimes have ongoing skin damage. They've got induration in the skin. It's fragile. There could be inflammation. I think that's unresolved chronic venous hypertension. And I think a lot of those patients have outflow obstruction.

The ulcers, I think, those patients, especially you'll find you've treated their superficial disease maybe they're perforators, and they're just not getting better. And those patients oftentimes have outflow obstruction.

The CEAP 4 patients, again, they're kind of pre-ulcerative. They have a lot of skin damage. They've got induration. The skin is thick, and it's fragile. And it's cracking, and it's prone to ulceration. The CEAP 3 patients may improve, but it's 50-50. That's what the data would tell us. And so if you're really looking for the patients that seem to respond best to evaluating as a group, it's really 4, 5, and 6.

MARIA VEGA: Thank you for the input.

DR PAUL GAGNE: Yeah. All right. So let's talk a little bit about what this pathology looks like. So this is what a non-thrombotic iliac vein compression looks like. You can see, as we all know, you have the spine, you have the iliac vessels confluencing to the vena cava as you see on the left. And then you have the aorta bifurcating into the common iliac arteries over that.

And depending on the orientation in the body, and this is everybody's unique anatomy. Sometimes the common iliac artery on the right historically has been identified as compressing the left common iliac vein. But we know that the right common iliac artery can also crossover as it does to go down to the right leg and compress the right common iliac vein. And we also know that these arteries can compress the veins along the length of the vein, not just at one focal spot. There's a lot of variability.

And we also know that where the internal iliac artery bifurcates off of the common iliac artery in the pelvis, both on the right and the left. It can compress the cranial portion of the external iliac vein and cause a stenosis at that point. So there are multiple points in the pelvis where the veins can be compressed leading to a significant stenosis and outflow obstruction.

This has been a big advance in our understanding in the last decade.

This is the other problem that we are often treating, and this is post-thrombotic disease. This is a slide courtesy of Dr. Comrata, where you see this dense scar within a common femoral vein. And this is what we're fighting through when we're dealing with a long segment occlusion, trying to get from the common femoral vein up to the vena cava in many of these patients.

What you see is sort of this Swiss cheese lumen where you can get a wire, you can get a catheter through there, but once you do that, you have to expand this lump of collagen with a balloon and stent. And you can tear the collagen with the balloon. But if it's not supported by a stent with good outward force, it's going to not stay open. It's going to compress. And so that's been the big leap forward with the new nitinol stent that the board has now made available to us, the Venovo Stent.

Is that it does keep this collagen plug open, so that we get better patency and better lumen gain.

OK, question number two.

MARIA VEGA: Question number two. The question is going to pop up in a few seconds. In the meantime, I'm going to read the question to you. What did the video trail teach us about iliofemoral vein imaging in CEAP 4 to 6 patients? So that's going to be the question that is going to come up.

Another question that we asked then is a little bit more relevant to this question as well. We asked the audience, do you currently use IVIS in venous interventions? It was A, yes, always used IVIS. And that was the majority of them with 46%. And then followed by 31% with intermittently they use IVIS. And 23% said no. What are your thoughts on that?

DR PAUL GAGNE: So 23% aren't using IVIS at all?

MARIA VEGA: Correct.

DR PAUL GAGNE: Yeah. So I use IVIS routinely. And there's two reasons for that. One is the more I've done this, the more I've seen detail with IVIS that you just aren't going to see anyway else. You're not going to see it on a venogram. You're not going to see it on MR venography. You're not going to see it on a CT venogram.

There's trabeculations. There's subtle changes across the lumen. You see a scar in the lumen that tells you that this patient may have a sclerotic wall. There's just detail that you pick up on IVIS that give you a little clues that there are points of compression, there are points of narrowing, that are limiting flow through these systems.

So these other imaging modalities can be helpful. But you need IVIS to not miss disease, because if you go ahead and do an intervention or an evaluation on a patient, and you send them away. And they've got an active venous ulcer, or they've got CEAP 4 disease. And you say, yup, you're fine. There's nothing wrong with you. And you've missed the diagnosis, because you didn't use IVIS. Then you've probably not served that patient well.

The second reason is you need to stent safely. And if you don't want these stents to embolize, you need to be able to measure the size of the vein. And these veins can change with respiration. And so you need to do a real time evaluation of the vein size to make sure you know how big that vein can get when that patient is taking a deep breath or [INAUDIBLE], so that that stent is not undersized and doesn't embolize to the heart and lungs. So I use IVIS routinely. It also cuts down on radiation.

MARIA VEGA: Yeah. So we get the answer for the question. The question was, what is the video trial teach us about iliofemoral vein imaging in CEAP 4 through 6 patients? The majority of them, with 95%, answered B and C, which is multi-planar venogram. Is that equip for identifying significant iliac and common femoral vein occlusive disease? And, oh sorry. I read the wrong one. B, intravascular ultrasound detects and diagnose significant iliac and common femoral occlusive disease more frequently than MPV in the same patients, and IVIS imaging changes the treatment plan of patients with iliofemoral vein occlusive disease compared to MPV.

So both, the majority of them got it right.

DR PAUL GAGNE: Sounds good. I'm glad that information is now well absorbed into our community.

MARIA VEGA: Yeah. Exactly.

DR PAUL GAGNE: All right. So, what do we need to know in the literature? So we touched on the video trial. And it was looking at the role of intravascular ultrasound versus 3-view multiplanar venography for diagnosing and guiding treatment of iliofemoral vein obstruction. It was a prospective, single arm study, 100 patients. 14 sites in the US and Europe with independent core lab adjudication of the intravascular ultrasound images and the venograms.

And what it showed is, as we talked about in the question, is that IVIS had superior diagnostic accuracy than multiplanar venography. And more importantly, you change the treatment plan in 57% of the cases.

And then, we did a post-hoc analysis of outcomes at six months, looking at VCSS scores in patients who were treated based on IVIS versus how they would have been treated with multiplanar venography. And what we found is that, the measurement of stenosis based on intravascular ultrasound pre-stent was able to predict a statistically clinical improvement when that cross-sectional area was greater than 50%.

Whereas a venogram diagnosis of a 50% diameter reduction or greater did not predict clinical improvement after stenting. So you could identify a lesion potentially on venogram. But if you stented that lesion, they did not necessarily get better. Versus, stenting after IVIS tended to predict clinical improvement. So that's a powerful statement.

Now what are the criteria for intervention? As I mentioned, it's been used for a long time for non-thrombotic regions of 50% cross-sectional area reduction. And it seems to correlate reasonably well with clinical improvement. This is a stenosis that's referenced to the adjacent normal vein. And the question comes up sometimes, well in arteries a 50% cross-sectional area reduction isn't much of a diameter stenosis.

The problem is, veins don't exist like arteries as circles. They exist as an ellipse. So when you do the math, a 50% cross-sectional area reduction actually correlates to a greater than 60% diameter stenosis if the circumference of the vein is fixed. And so that is why a 50% cross sectional error reduction in veins actually makes some sense.

But in post-thrombotic patients where you may not have a normal vein for reference, or where the vein may be nearly occluded, then how do you know what the size of the true vein is? Well there's a couple of strategies. You can look for adjacent segments on ipsilateral leg. Maybe your common femoral vein is measuring 14, and your external and common iliac veins are occluded, well that means that probably your external and your common need to be 14 to 16, or at least that.

But you can always look at the contralateral leg, if it's normal, and see what the size of the veins are there. And then if all else fails, theoretically some studies that have been done and published previously have shown that on average the common femoral vein should be about 12 millimeters. The external iliac veins should be about 14 millimeters. And the common iliac vein should be about 16 millimeters.

Now obviously, there's a lot of variation in that. Patients depending on their body habitus and their size--

[PHONE RINGING]

--and so. Excuse me. And so there is some variation on your initial intravascular ultrasound imaging. But this is a guideline for choosing the correct size stent in the post-thrombotic patient. Now how do you get started?

So there are several options for access to the deep venous system to do these evaluations. Personally, the popliteal vein is my favorite. The access is fairly simple, although the patient does have to be in the prone position. So not every patient is able to do that. And patients, I find, that have particular problems with that position are those that have chronic back pain, COPD, the grossly obese, and then sometimes in patients who have severe post-thrombotic disease. The femoral popliteal veins are occluded or markedly diseased. And it's not a great place to get started.

The mid thigh femoral vein is actually one of the more common places to access. It's not the common femoral vein, and it's not the saphenous vein. It's the mid thigh femoral vein. And the reason you want to go here rather than the common femoral vein or the greater saphenous vein is that it allows you to evaluate the entirety of the common femoral vein and the confluence of the deep femoral vein and the femoral vein. So that you know your landing site caudally is patent and is wide open so you have good inflow, because if you don't have good inflow on your stent, it's not going to stay open.

And so you really want to be inferior and peripheral to the lesser trochanter of the femur to make sure you're below the confluence of the profunda femoris and femoral vein.

The other thing you want to be careful about is avoid a 90 degree sheath. So sometimes an extremely obese or large thighs, an 11 centimeter sheath may be too short, as maybe the access needle. And if you have to deal with the thigh that's large like that, going in at 90 degrees can make the subsequent intervention difficult. And so then you may want to think about a different access site such as the popliteal vein, or the third most common option, which be the internal jugular vein.

It's not my favorite, but it's actually quite functional. And a lot of people use it routinely. It gives you access to both legs, the iliac systems bilaterally, down to the femoral vein in most people. Sometimes it's hard to cross some lesions if you don't get enough support even with the sheath. But generally you can even cross the most complicated post-thrombotic lesions.

It's hard to work and deploy stents bilaterally at the confluence of the common iliac vein and cava if you do them in kissing stents without doing a second puncture. But all these are technical challenges that certainly can be overcome.

Now as far as imaging is concerned, we always start with duplex ultrasound. But we don't just image the infra-inguinal vessels, we also image the iliocaval vessels to look for any evidence of scar, compression, or chronic occlusion. And then, most of the time we proceed to venography and intravascular ultrasound.

We do a venogram from our leg axis side if not the internal jugular to look at the entirety from the lesser trochanter. So that we see the confluence of the profunda and femoral vein up to the vena cava. And then, we'll look at the IVIS imaging in a pull through, typically from the level of the renal veins down through the cava, through the common and extra iliac veins and the common femoral vein.

We look at the cava to see if it's distended, because some patients you'll find just have a big dilated vena cava. And that means they've probably got some fluid overload. They've got some right heart failure. And we've had a number of patients come to us with chronic problems in their legs that could be chronic venous hypertension. They've been cleared by their cardiologist, saying there's no issues with their heart. And yet their vena cava is chockablock full, and they're just fluid overloaded, either from right heart pressure, elevation, or some renal issues.

We use the 0.035 system with the IVIS catheter, because it really is the only catheter size that gives you the proper field of view for these big vessels. This is an eight to eight and a half French system. The five and six French systems just don't show you the entirety of the veins.

We intermittently will use axial imaging, especially if we have somebody who has extensive post-thrombotic disease to help plan the procedure and the duration of the procedure. And sometimes, whether we do this in an outpatient setting or at the operating room, patients who have a long standing filter and/or have bilateral symptoms and a history of DVT especially up in the pelvic veins, we'll get a CAT scan to help plan the procedure.

And then finally, if we have a patient that has a rapid onset of symptoms in the last 6 to 12 months, then we'll get a CAT scan to make sure they don't have a neoplasm as part of the problem.

And now for our third question.

MARIA VEGA: OK. So our third question is, what chronic vein pathology can acute deep vein thrombosis result in? So the question is going to be up on the poll, and we're going to give it a couple of seconds there. In the meantime, Dr. Gagne, I wanted to ask you. You said that the jugular access is the least commonly used access site. I have met some physicians that do it all the time, some that just shy away from it. Can you tell me why some physicians are just completely hesitant? And also you said the popliteal access, I think, it's good, and it gives people access to the lesion. Can you give a little bit more insight on choosing jugular access versus popliteal access?

DR PAUL GAGNE: So, I think jugular access is not my favorite, but I do think for some people it's their preferred technique. So I think there's a lot of dealer's choice in that, physician choice as to whether it's popliteal or jugular. I used to tell people that I used the popliteal preferentially and most of the time accept in patients they wouldn't tolerate it. But then I looked at my data. And I was actually using the mid femoral vein 55% of the time. The popliteal 35% or so of the time, and the jugular 15% of the time.

So I think that the reality is that the popliteal can't be used in a lot of patients. I think that the jugular is great access, because the vein is relatively superficial. It's easy to get hemostasis at the end of the procedure. You just sit the patient up t 30, 40 degrees, and you've got hemostasis.

The thigh can be a deep place to work in some patients. You get some hematomas and some bruising, although it's usually not something that requires anything more than conservative treatment. I think the most important thing is that you need to be able to evaluate and treat the entirety of the common femoral vein from the profunda up to the cava.

And if you have a tall person, coming in from the jugular in some cases may limit what technologies you have available to use. One of the advantages of the jugular is that if you have a diseased femoral vein with a lot of scar, and you've got some disease in the profunda femorous vein, but in general it's open, you have the ability to stent down into the profunda femorous vein and improve the flow directly from the deep vein, into your common femoral vein, and through your iliac vein system.

So there is an advantage in that setting to be able to come in from the jugular vein.

MARIA VEGA: Thank you for that. We do have the answers for the question, what chronic vein pathology can acute deep vein thrombosis result in? The correct answer is E, all of the above, which is intraluminal web, intramural scars sclerotic vein and [INAUDIBLE] small lumen, occluded vein, intraluminal scar, and luminal stenosis. So the majority, 92%, got it right.

DR PAUL GAGNE: We have a smart group tonight.

MARIA VEGA: Yeah we do.

DR PAUL GAGNE: All right. So this is an example of what you'd be looking for. This was a patient who as a young woman at the time of pregnancy got a DVT, and then had a swollen left leg for the next 4 years. And we got this CAT scan to see what was going on, because 40 years ago, there were some interesting treatments for DVT including ligation of vessels.

And what we saw was this very sclerotic, as you can see with the pointer, this very sclerotic vein underneath the iliac arteries across the front of the spine. You can see here, it's just really a wisp of scar tissue. You don't really see any lumen. And you can see it here as well.

And then if you look over here, you can see the small partially open external iliac vein and the normal contralateral vein. These are the types of things you want to check on CAT scan, because sometimes when you order a CAT scan, especially at a center that has a lot of general radiologists who aren't used to looking at this type of pathology, you don't necessarily get it reported in your report.

So you want to look at these things yourself in order to see if there's abnormalities. I find CAT scan can be very specific when you see an abnormality. But it misses a fair amount of disease.

Now this is, as I think as we've talked about, IVIS is really the primary imaging modality for diagnosing disease and then measuring the size of the vein. You can see here on the left it's a very severe external iliac vein compression stenosis. You can see the cross-sectional area, only 37 millimeters.

We're really looking for something between 100 and 150 millimeters. But on the right, you can see a much more normal adjacent segment measuring 135 millimeters squared. And this was the inferior external iliac vein of the same patient.

And so this calculates out to a 75% to 80% cross-sectional area reduction. And you can see on the right panel in the lower left of the picture, the area is 135 millimeters squared. The middle of diameter is 10.6. The maximum diameter is 17.4. In order to get a sense of what your vein diameter is, you add the two up, divide by 2. So that's 28, divided by 2 is 14. So that's a 14 millimeter vein.

And assuming when you have your IVIS, and the patient takes some deep breaths, there's no phasic changes with the vein opening and closing. And I've seen a 30% change with respiration. So you do want to do that. But assuming this is the fixed size of the vein, that if you were going to stent you, you would want to get a stent that's larger than 14 millimeters. And the IFU for Venovo is one to three millimeters. And that's your range. A 16-millimeter stent would probably appropriate here.

Here's some other pathology that you'll pick up on IVIS. You can see here on panel one, this white echo coming through the center of the lumen. Here's the artery. Here's the vein. Here's a web coming up through the vein. And you can see that the vein itself is, in fact, the same size or smaller than the artery. And we know that the veins should be much bigger than the artery. As you see here, a normal vein next to a normal artery.

So the fact that this vein is shrunken, it's got this hyperchoic echo right through the middle of the lumen. This is post-thrombotic scar and sclerosis of the wall. You can see here these little chunks like little rocks on the edges, this irregular border, again this is post-thrombotic disease. The vein is open, but the vein is not as big as it should be. It should be much larger compared to the artery.

This is the smallest shrunken vein. You pick up these abnormalities on IVIS. It'll be an open vein on venogram. It will be an open vein on CAT scan. But if you see these abnormalities, this is not a compliant vein. This is a stiff vein that does not conduct blood normally. And this is the type of abnormalities that you can treat with stenting.

And then finally, this is a very subtle web that you pick up on IVIS. And in fact, it's so subtle. And this is a patient that had no stenosis. The patient had no history DVT. It has this web in here. And this web here you look at and you go, well, is that really something?

And then you put a balloon up. And I will tell you that I took my foot off the pedal, because the waist started right about over here. And this was a bow-tie. And you can see this tight narrowing, and you treat these patients and their stasis dermatitis, and their edema, and their induration goes away.

So if IVIS is so helpful, why do you want to do a venogram? Well if you see collaterals, that's a pretty good tip off that you have a pressure gradient. So it's always nice to see those when you start your intervention. You make sure you put your wire in the right place. You know exactly where you are. And then, especially after stenting, you want to see what the flow through the stent is. Is there spontaneous washout of contrast as the patient breathes?

You can push the contrast out with bolus of saline. That's not going to tell you whether the stent is going to stay open or not. If you have spontaneous drainage of contrast and good wash out with just deep breaths, then you know that stint has good inflow, good outflow, and it's likely going to stay open in the post-procedure period.

Now my protocol for evaluating for a non-thrombotic iliac vein lesions, NIVLs, is I put my catheter up at the renal vein, and I do a pullback down to the level of the femoral vein. And that allows me to assess the inferior vena cava for any phase changes to see if the patient is fluid overloaded. I get a good look at the common iliac vein, the confluence of the right and left common iliac vein with the cava. Sometimes the inferior vena cava at that level is small, and sometimes the common iliac vein is actually larger than the inferior vena cava just above the conference.

It's good to know about that if you're stenting into the IVC. And then I want to see what the vein segments of the common and extra iliac vein look like. And I want to see what the origins of the femoral and deep femoral veins look like and where they are. So that if I'm stenting into the common femoral vein, I try not to jail that inflow into my stent.

And I also see the pathology we've shown in the preceding slides. And then I look for the compression that we've talked about. If I do my initial pullback, and I don't really see much of anything, I put the catheter back up at the caval iliac conference, and do a very slow, steady, tedious pullback looking for discrepancies in vein size that could suggest a pressure gradient, areas of hyper-dense echo in the wall that might suggest prior scar, and then the occasional web that you see.

And then if you go ahead, and you don't see anything. And let's say the extra iliac vein is measuring 90 millimeters. You know, there's some discussion about whether it needs to be 125 millimeters squared. And I think in general, we don't have good data to support those kind of numbers. So I would say that if the veins in general look normal, and you can't really find any pathology, especially if the vein seems to match the body habitus of the patient, stenting may not be the right thing to do.

Now this is what post-thrombotic imaging can look like. You start off with the venogram. The collaterals will be evident. You can then see where the normal vein ends. And a lot of times as you can see here, in this little wisp of the common femoral and extra iliac vein, a track that you can then feed a wire up through. And once you get your wire through, you can start to balloon dilate. I typically would start with a 4 or 6 millimeter long, 15 or 20 millimeter balloon to create a channel.

And then I'd just start going up to my larger balloons. And usually I'll go up to a 14 and 16 Atlas balloon in order to disrupt the scar in that track. And once you've dilated to the size that you want, then go ahead and deliver your stent from a part of the vein that's open so you have good inflow to a part of the vein that's open up above so you get good outflow. And then you post dilate up to the size you want that vessel to be.

And then I do it an intravascular ultrasound image to make sure that the vein is opened up adequately, so that I don't have any persistent narrowing that could threaten the patency of that stent. And then I do a venogram to make sure I have good spontaneous wash up, because if contrast is just sitting there, it's not going to be a successful revascularization.

And we'll look at a case of this a little later on where we had a great result with the new Venovo system. When we do treat the post-thrombotic patients, we want to treat the entirety of the disease segment. If we overlap stents, it's usually two centimeters minimum so that in the torturous anatomy of the pelvis doesn't get stent separation that can then lead to stenosis and thrombosis.

We talked about inflow. We talked about post-dilating. You really want your stent to be 12 to 40 millimeters in size or bigger after it's been deployed and post-dilated.

All right, so the venous anatomy comes in a variety of flavors. And you can see here different anatomy. So you have a short common iliac vein. You can have a long common iliac vein, and that's relative between the conference and the take off of the internal iliac vein. You can see the external iliac vein coming down to the common. And sometimes there's a duplicated deep femoral vein coming off of the common, or joining the common rather than a single vein, as is taught in the anatomy books.

Identifying these nuances and differences in anatomy is important in planning your stenting. And although we think that the average size of these veins based on anatomy studies is 12, 14, and 16 millimeters, not everybody's veins are those size. And so they do not have to be that size if they otherwise appear to be normal.

So how does the anatomy play into how you place a stent? Well if you've got a classic May-Thurner lesion, oftentimes you have some pre-stenotic dilatation. So you could have a vein here that measures a lumen of eight millimeters at the top of the common iliac. You may have a vein here that measures 23 millimeters. And you're thinking, well, this is supposed to be about a 16 millimeter common iliac vein.

If you go ahead and stent here, you're only going to have wall apposition here. So what we oftentimes will do is we can either extend a stent down from the external iliac vein all the way through the stenosis and just into the IVC. And this is where the flared end on the Venovo Stent is nice, because you don't have to extend too far. The flare will help not only to oppose the stent down here and give you good anchoring, but up here, it can keep the artery from rolling over the end of the stent and make sure that you open up the vein and don't have a late re-stenosis.

But you can put a smaller stent here and extend a bigger stent telescoping it in size, so that you'd fill this up and get a proper sizing, say 14 here and 16 here. You don't want to put a 23 millimeter stent in here, because it's going to be too big in the cava. And it's going to threaten the outfall from the other leg.

If you have a long common iliac vein like this, then you can anchor it down here, and come up through the stenosis here. And if you have a narrowing in this section of your right common iliac vein, then you don't have to extend all the way down into the external iliac vein. So depending on the length of the common iliac vein there are different strategies for stenting.

If you look here, the external iliac vein especially has a very tortuous course in the pelvis. It starts a little straight, then it dips down deep into the pelvis, and then it flattens out, and comes up the superficial again at the level of the inguinal ligament. And so, there's really three parts. There's this initial straighter part. There's dipping deep part, and then this later superficial part of the common femoral vein junction.

And so, I call it the rule of thirds, because if you go ahead and you stent in this dipping part, at the end of your stent, either the caudal or the cranial end of your stent, ends down here in the dipping part of the external iliac vein. You can see on this lateral view, the vein down here.

Then what's going to happen is the stent is going to want to straighten out. And you may get a little narrowing created just by tension on the vein wall. So when you stent, you want to stay in the upper third, two to three centimeters of the external iliac vein, or the lower two to three centimeters of the external iliac vein. And sometimes that means you need to make the stent longer if you need to come all the way down to here. Or you go off from the common femoral. And sometimes you may need to extend all the way up here, trying to avoid ending your stent either cranial or caudally in this middle third.

And it will make your stenting easier, and there's really not any consequence to having a longer stent.

Now this is again just emphasizing, if you have a common femoral lesion and you've got disease extending across even a ligament, then you would need the stent north. You don't want to end up in the middle here. You want to stay in the lower third of the external iliac vein or extend it up higher. And again, this is an example of extending it up higher, past the middle third of the external iliac vein. You can avoid complications of tenting and narrowing the vein.

And then here, you typically want to oversize your stent. So let's say this is a 14 millimeter external iliac vein. You've got an eight millimeter narrowing here. You've got a 23 millimeter pre-stenotic dilatation. If you take a 16 millimeter stent, you extend it 2 to 3 centimeters into the external iliac vein, that will anchor in the external iliac vein. And even if it's free floating here in the pre-stenotic dilatation and fixed here, this stent not only will not go anywhere, but it will give you the 16 millimeter lumen here that you need to get good hemodynamic flow and get rid of your chronic venous hypertension.

So in some cases, you want to anchor your step down here, especially with a short common iliac vein that's dilated. Over here, you can see again if this is a 12 millimeter external iliac vein, you may want to stent up with a 14 millimeter stent to here, and then telescope out of that, putting the 16 millimeter stent inside the 14. That anchors the 16 and 2 to 3 centimeters of the 14 millimeter stent, so it's not traveling anywhere. And it gives you a good scaffold to open up the compression point, which may be 8 and that will be 16. And you don't have to have wall apposition here, and you'll get a good outcome.