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Fixing Femoral Flow with the Endologix DETOUR System: Clinical Trial Results in Practice

Author Thomas O'Rourke covers Fixing Femoral Flow with the Endologix DETOUR System: Clinical Trial Results in Practice on BackTable VI

Thomas O'Rourke • Dec 21, 2023 • 114 hits

Percutaneous transmural arterial bypass (PTAB) with the Endologix DETOUR system has shown promising clinical trial results for its ability to bypass flow through damaged segments of the femoral artery. As with any innovation in medicine, there are some important considerations to make before PTAB can be fully implemented into everyday practice. Although this transition can sometimes be difficult, it is made easier with insights from Dr. Sean Lyden. He discusses his knowledge of PTAB as it relates to training, cost, complications, and use in everyday practice.

This article features transcripts for the BackTable Vascular & Interventional Podcast. We’ve provided the highlight reel here, and you can listen to the full podcast below.

The BackTable Brief

• In clinical trials thus far, no increase in venous morbidity was observed using the venous clinical severity score and the Villalta score.

• The full cost of the Endologix DETOUR system is yet to be determined, but according to Dr. Lyden, it has the potential to be safer and more cost-effective than the current standard of care.

• It is important to start with simpler cases that match those of the clinical trial before attempting to use the DETOUR system for more difficult cases or off-label use.

• Post-procedural leg swelling is a common and expected response following PTAB due to blood flow restoration. Patients can manage this at home with compression socks and leg elevation.

• A patient who undergoes PTAB will have a non-compressible flow channel running through the femoral vein. This may result in DVT misdiagnosis in emergency settings.

Fixing Femoral Flow with the Endologix DETOUR System: Clinical Trial Results in Practice

Table of Contents

(1) PTAB Training, Cost & Clinical Efficacy

(2) Transitioning from Clinical Trial to Clinical Practice

(3) Navigating PTAB Side Effects & Complications

PTAB Training, Cost & Clinical Efficacy

Dr. Lyden emphasizes the importance of comprehensive training for clinicians, a prerequisite set by Endologix and the FDA, to ensure optimal use of the DETOUR system. The commitment to training reflects a proactive approach to minimize complications and improve patient outcomes. The cost of this technology remains uncertain, as it is still under review by value analysis committees. However, the Detour System presents a compelling value proposition by offering a solution for complex lesions that current technologies cannot address. Notably, the system shows superior two-year patency rates compared to traditional PTFE femoral-popliteal bypass, with fewer wound complications. This advancement in PTAB is not just a leap in procedural technique but also a step towards reducing post-operative complications, highlighting its potential to become a standard approach for certain vascular conditions.

[Dr. Sabeen Dhand]
Do you think is there a plan as far as say, "Once I can get it at my hospital"? Is there like a training or proctor type of system for this, or just go ahead and do it?

[Dr. Sean Lyden]
No, a lot of the discussion, because this is a novel device and it's really tried to become a therapy, was that the agreement with Endologix and the FDA part of the approval process is there will be a mandatory required training. I've already done mine and I've helped lead one. They know they've done three so far nationwide, and so that's going to slow the rollout, but I look when there's a new unique therapy, the best thing a company can do is make sure that you have everybody as trained up as they can be so their results are good.

I'm sure it'll frustrate a few people waiting to get their hands on it, but I look at it that when EVAR came out, if we hadn't spent a lot of time training people, we'd had a lot more complications, and so when things are new, sometimes spending a little extra time to show people how a device works, talk through good case planning, talk about lessons learned in the trial, about cases that are good for the trial and cases that are bad and those kinds of things are kind of unique.

[Dr. Sabeen Dhand]
I know. My mind is already running about different cases that I can just use this on. I had a case last week of just totally occluded stents in the fem-pop, I mean, 10 years. This would be perfect just bypass that easily with a nice landing zone in the pop. What about another elephant in the room is cost? Is this going to be like a $20,000 device or is this going to be something that is very easy for smaller hospitals to use?

[Dr. Sean Lyden]
That I don't know yet. As of at least the last time I talked to Endologix, about 10 days ago, they had not said all on the cost. I said that I had already talked to our endovascular new product committee at the Cleveland Clinic because we were part of the trial. I had exemption on worry about cost on the first case so we can evaluate it, but then it'll go to our value analysis committee to decide how and where it can be used. To me, the argument of what's going to help get it through most value analysis committees is it will provide a solution that current technology doesn't. It'll allow treatment of patients that don't, and if you look at the durability of endovascular devices for these kind of lesions, it's terrible. At least the two-year data that we now have available, the patency is better than what it would be of a surgical PTFE bypass.

[Dr. Sabeen Dhand]
What is the two-year patency for this now?

[Dr. Sean Lyden]
I just presented it at the Vascular Annual Meeting. I think you have to realize there's a couple of things to talk about. If you talk about the different definitions of patency, the trial defined patency as that there was not a clinically-driven target lesion revascularization, and by duplex, there was not a peak systolic velocity ratio greater than, equal to 2.5. The reason why I point that out is from PTFE bypasses, duplex is completely not helpful in predicting stenosis or occlusions. If we took the patency as defined, it was 59.4% at two years, but if we just look at the freedom from clinically-driven TLR, it was 76%. Then if you look at it just the way we do a PTFE FEM bypass, is it open or not?

With a PTFE fem-pop bypass, I could get a duplex today and it looks perfect. I get a duplex and it has a stenosis and it goes on to be fine or thrombosis the next day. For most of the studies we looked at, the patency at two years is probably somewhere between 60 and 70%, and this trial, if you look at 24 months, open or close, it was 87.6%. The key is then you don't have all those wound issues. As a vascular surgeon, PTFE FEM bypass, we'll brag it's two hours, it's an easy case until you develop a wound infection that goes down to the graft, which is then catastrophic to the patient in terms of limb loss. That's, to me, the other exciting thing is I can do something I could do surgically without all the wound issues.

[Dr. Sabeen Dhand]
Yes, it sounds like if you're going to do a proximal SFA to PTFE bypass, you're not going to do that open anymore. You're going to do it via the Detour. There's no point.

[Dr. Sean Lyden]
Exactly. If they needed something done to their femoral profunda, I would still do that, but otherwise, if I don't need that or if I can do that beforehand and stage it, I'm doing this every day.

Listen to the Full Podcast

Percutaneous Transmural Arterial Bypass (PTAB) as a Treatment Option for CTOs with Dr. Sean Lyden on the BackTable VI Podcast)
Ep 364 Percutaneous Transmural Arterial Bypass (PTAB) as a Treatment Option for CTOs with Dr. Sean Lyden
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Transitioning from Clinical Trial to Clinical Practice

Clinical trials have inherent limitations to them due to adherence to strict procedures. Dr. Lyden believes that the DETOUR system will be used for many off-label interventional strategies post-FDA approval. The system is already capable of shortening treatment time for extremely calcified femoral-popliteal lesions, and could potentially have applications in other similarly calcified lesions. Dr. Lyden emphasizes, however, the importance of starting out using the DETOUR system on cases that best match those of the trial. Once trial outcomes are replicated in practice, physicians can then investigate unique approaches.

[Dr. Sabeen Dhand]
You said it has to have a single patent tibial runoff. Can that be a recanalized tibial during the procedure or it needs to be a–

[Dr. Sean Lyden]
For the trial, it couldn't be. Now, once it's FDA approved, I'm sure people will want to do what they can, but we know from endovascular treatment that the more tibials you have open and the bigger the tibials are, the better that anything we do in the fem-pop segment is going to be, so I'm sure this device will be no different. Once it's FDA approved, you have someone with severe disease and you treat their tibial and have a good result, I am sure there will be people that get treated with PTAB. Hopefully they do a bunch of it right about it, but at least during the trial was excluded.

[Dr. Sabeen Dhand]
It's going to be quite remarkable to see what kind of quote off-label techniques people are going to use with this in different areas. I think it's going to be pretty remarkable.

[Dr. Sean Lyden]
To me, the unique thing is I've always felt that when I have some of the flush SFA occlusion, it doesn't reopen into a tibial. If you're going from a 5, 6, 7 millimeter proximal vessel into a 3-distal and you have to treat it, the results are never as good. I think that's something that we saw if we looked at the BEST trial, whereas the BASIL trial was really more just tibial disease. If you could actually have a good treatment of the below-knee POP and tibial and get a good outcome, I think it would completely change the durability of having a PTAB in there to treat the occluded femoral popliteal segment. To me, that person with reoccluded stent graft that's super, super calcified lesion that you spend forever trying to use etherate to be on or lithoplasty on or-

[Dr. Sabeen Dhand]
Long case.

[Dr. Sean Lyden]
-stents designed for that, they're long, long cases, and if I can just avoid all that.

[Dr. Sabeen Dhand]
A hour-and-a-half sounds amazing.

[Dr. Sean Lyden]
Right. Exactly. Anybody who has a bunch of this in their practice, you tell them, "You can do this an hour-and-a-half," they're like-

[Dr. Sabeen Dhand]
Yes, sure.

[Dr. Sean Lyden]
"Okay." Then they'll do it, and they'll say, "No, it really wasn't that hard."

[Dr. Sabeen Dhand]
Yes. Sean, this has been great. Any kind of parting words of wisdom to people who are either familiar or unfamiliar with Detour and thinking about bringing this into their practice?

[Dr. Sean Lyden]
Hopefully we'll have the report out there of the outcomes for one year of the JVS as where we're going to plan on submitting it to you, hopefully in the next week or so. The trial results for the two-year presented at the Vascular Annual Meeting, so they will be available through that format. I just tell people when you're getting new devices and having trained people on carotid stents, SFA stents, atherectomy devices, EVAR devices, TEVAR devices, look at what the trial looked at, try to make those your first patients. Don't try to do the hardest case your first case, and once you're good at it, then kind of live off, kilter a little bit, trying to do something harder.

You can play around a little bit, but I always tell people that I always do the straightforward, simple cases because I want when I now have the device in my hands to prove I can continue to do what I did in the trial and that my results are good, and not to sit there and find the worst, hardest case that everybody would say, "You did it and it's great." You want to sit there and reproduce those outcomes from the trial of your own first before you start doing the really toughies.

[Dr. Sabeen Dhand]
Yes. No, that's great advice. Don't start off with something so hard and with the new device, that's just going to make things 10 times tougher. Sean, thank you so much. Thanks for taking the time to be on our podcast today and teach everyone about Detour and PTAB. I think it's something-- it's almost-- this thing is too good to be true. All the stuff you're saying, it's so nice. I'm really looking forward to now seeing it in clinical practice in other people's hands, and hopefully we can bring it into my practice too. This sounds great. literally my mind is already spinning with multiple patients who'd benefit from this. Thank you so much. Thanks, Nick, for being our engineer today. We look forward to seeing you again, Sean. Thank you.

[Dr. Sean Lyden]
Thank you so much for having me. It's been my pleasure.

Navigating PTAB Side Effects & Complications

Early clinical trials show that PTAB is a reliable procedure with minimal severe complications. Venous Clinical Severity and Villalta scores for the trial showed that through one year there was no increase in venous-related mortality. Minor complications such as leg swelling are common, but normal and not life-threatening. Leg swelling, for example, is a normal response once proper blood flow is restored to the leg. Most of these cases can be managed at home with compression socks and leg elevation. It is important to educate patients to avoid unnecessary ER visits. It may also be beneficial to send patients home with information on PTAB to share in any future ER visits. PTAB alters the flow and compressibility of the femoral vein, which may present on an ultrasound as a DVT. While not a direct complication, it is important to avoid misdiagnosis.

[Dr. Sabeen Dhand]
That's awesome. I honestly I'm very excited to see this. One thing is kind of hard to talk about, too, but did you see any kind of weird complications during your experience with Detour that were unexpected, the stents causing a dissection or anything like that?

[Dr. Sean Lyden]
No. The one big complication we had during the trial was when we stopped requiring CT scan ahead of time and we allowed people treatment of common femoral disease concomitant with the procedure with a good outcome, the one acute occlusion we had was a person who had a common femoral atherectomy and into the profunda origin, and when we looked at the CEC, looked at the films after the case, they really didn't get the lumen of the common femoral profunda open enough, and that acutely occluded.

The other key thing is, I think, something that anybody who does any ultrasound imaging or does any interventional radiology will realize is that you get a film around the stent grip. No different than if you have a tunneled center lining or dialysis lining, they get fibrin sheath lining that device. I think one of the reasons we don't see the late DVT and PE risk is this device basically it's a fibrin layer around it. The normal way you define DVT on an ultrasound is lack of compressibility, lack of flow.

The Core Lab had to come up with new definitions because you now have a vein that you can see a flow channel, you can see it compress, but it won't compress all the way because it's now arterialized, and so if it's a duplicate vein, it's easy, but if you don't, it's not. I think the one thing that we're going to have to get out there is that when someone has this and the patient is going to have to know or maybe have some sort of card to help the ERs when they come in with leg swelling for some other cause that it doesn't get reported out as a DVT because the ultrasonographers are not going to know what they're looking at when they see.

[Dr. Sabeen Dhand]
They're going to be like, "What is that flow channel?" I actually would love to see what that ultrasound looks like, that there's this like graft within a vein and it's flowing the different flows. It probably looks pretty gnarly.

[Dr. Sean Lyden]
It works really well, but I tell you we had to basically modify the definition of DVT. We saw this fibrin sheath usually like a millimeter thickness, but it's no different than any other prosthetic device you live with in the venous segment. I think the key to remind people is that, hey, we put a new arterial channel in the vein. It's okay. You cannot squish because that's pressurized artery. You're going to compress the remaining venous channel, and at least through two years, we've only had that 4% instance of DVT and we should have the three-year data soon by this fall. We'll hopefully present it at a meeting next spring.

[Dr. Sabeen Dhand]
Back to the creating that channel. Any issues with deep venous reflux and someone who might have like superficial venous reflux, too? Did they have worse leg swelling or some symptoms like that?

[Dr. Sean Lyden]
In the trial, we did look at the venous clinical severity score and the Villalta score through one year and there was no increase in venous morbidity. It was not collected out after two years, mostly knowing that when you harvest the femoral vein, if they don't have a morbidity by year, we've not seen that in the surgical literature, and so it's no different than if you harvest the femoral vein from something else and you tie it off, they do get a little bit of leg swelling from the calf down. I tend to put my surgical patients on compression stockings. I've done the same with my PTAB patients, just said it's going to swell a little bit, but six months later, it'll be completely back to baseline, and that's what I found.

[Dr. Sabeen Dhand]
Yes, I'm sure. Their extreme claudication went away that, they don't mind the little swelling.

[Dr. Sean Lyden]
No, they don't care at all. It's no different than if you revascularize those people endovascular surgically, their legs swell. I always remind myself when patients come back to the ED because they have a swelling issue, it's usually because I forgot to tell them that once I restore flow, they're going to swell, and when you remind people that that's going to happen and say, you need to put ACE on or elevate your legs, they're always, "Oh, yes, that means the flow is better. I'm so happy, Doc." As opposed to when you forget, they call the ED and they're like, "No, that's normal. You don't have a DVT. I know you're going to get a DVT ultrasound, but it's fine."

Podcast Contributors

Dr. Sean Lyden discusses Percutaneous Transmural Arterial Bypass (PTAB) as a Treatment Option for CTOs on the BackTable 364 Podcast

Dr. Sean Lyden

Dr. Sean Lyden is the chairman of vascular surgery and a professor of surgery with Cleveland Clinic in Cleveland, Ohio.

Dr. Sabeen Dhand discusses Percutaneous Transmural Arterial Bypass (PTAB) as a Treatment Option for CTOs on the BackTable 364 Podcast

Dr. Sabeen Dhand

Dr. Sabeen Dhand is a practicing interventional radiologist with PIH Health in Los Angeles.

Cite This Podcast

BackTable, LLC (Producer). (2023, September 11). Ep. 364 – Percutaneous Transmural Arterial Bypass (PTAB) as a Treatment Option for CTOs [Audio podcast]. Retrieved from https://www.backtable.com

Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.

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