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

[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.

[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."