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Dr. Hady Lichaa: Hello, everyone. This is Hady Lichaa, Interventional Cardiovascular Specialist from DocWire News, and I have the pleasure of having Dr. Matthew Bunte with me today. He is a world expert on vascular interventions and cardiac interventions. Extremely accomplished, had the opportunity to start building a deep venous arterialization program within their limb salvage program, and we’re kind of wanting to discuss this with him today. How are you, Dr. Bunte?
Dr. Matthew Bunte: I’m great, Hady. Thanks so much for having me today, and looking forward to the discussion.
Dr. Hady Lichaa: Yes, sir. So, if you can let the audience know about what you do mostly, especially on the endovascular side, and then we can delve into the topic.
Dr. Matthew Bunte: Yeah. Well, hello, everybody. I’m Matt Bunte. I’m from the Saint Luke’s Mid America Heart Institute in Kansas City, Missouri. I also am an associate professor at the University of Missouri Kansas City School of Medicine, and I’m the Director of Vascular Medicine for our health system. And my endovascular practice includes both artery and venous interventions, but more heavily focused on peripheral artery disease and chronic limb-threatening ischemia, which is how I got involved in the, we call it now transcatheter arterialization of the deep veins of that procedure.
Dr. Hady Lichaa: Excellent. So, tell us first, what is this procedure? What are we talking about here?
Dr. Matthew Bunte: Yeah. Approximately one in five patients with CLTI really have very challenging anatomy that makes them unsuitable for durable options of bypass surgery or durable balloon angioplasty. So, we call these patients so-called no-option patients, who really have exhausted endovascular surgical revascularization opportunities. And so they end up, many times, with an above or below the knee amputation. So, that’s really the group of patients we’re talking about here, not an infrequent population.
Dr. Hady Lichaa: Excellent. And what does the procedure consist of? Just a general guideline.
Dr. Matthew Bunte: Yeah. Yep. Most of the time, the issue for our diabetic patients or those with end-stage renal disease have very heavily-calcified small artery disease into the foot, so-called SAD disease. And that SAD disease is very difficult to treat, even with aggressive atherectomy techniques, and so these patients are typically those with desert foot. So desert foot being really no named vessels supplying the mid-foot or forefoot, and really no suitable expectation that if they have a wound in the forefoot or mid-foot that they’re going to heal without some additional flow.
So, what this procedure does is it borrows the veins in the foot and makes an arterial-to-venous connection in the proximal leg, where there’s usually some preserved inflow. And then through the veins, usually the posterior tibial vein, as was studied in the PROMISE-2 study, about 94% of the patients in that study, we borrowed one of the two paired posterior tibial veins. And we line that vein with essentially a self-expanding covered stent graft, all the way down to about the level of the calcaneus. And in the middle of the foot, there is a large venous plexus, called the lateral plantar vein, that has both superficial and deep connections. And that venous plexus then is perfused with arterialized blood and retrograde perfuses the venules, and eventually the capillary beds to supply the foot.
Dr. Hady Lichaa: Excellent. So, basically you’re creating an AV fistula at different levels, and obviously we’re going to ask you also about the different levels that you apply in every patient, depending on the anatomy. The blood flows from the artery into the vein in a retrograde fashion to the capillaries. Then tell us how does the patient kind of have a venous return at this point since you’re reversing the flow in the vein?
Dr. Matthew Bunte: Yep, yep. That’s a great question. As you’d imagine, we’re now putting a lot more blood flow into the veins all of the sudden with this procedure, so swelling is pretty common in the lower extremity. It’s a little tricky because just as you would manage a fresh arterial venous fistula for an end-stage renal disease patient who’s planning to use that fistula for dialysis, it takes a little bit of time for that to mature. And the same is true for this technique, that arterial of the veins is not an immediate process. It does take about three to four weeks to really set up and start providing real demonstrable perfusion to the tissue beds.
It is interesting that this procedure, even when the graft goes down, those little connections seem to be pretty well-preserved. And we’ll probably get into that later in our discussion. But effectively, this is not a quick fix. This is a procedure that does take a little more time for the circuit to mature and set up. And so that is a big difference between what we would consider a conventional angioplasty.
Dr. Hady Lichaa: And tell us your thoughts on proximal DVA versus distal DVA. Tell us what the differences are, where the connections are, and how different are these procedures?
Dr. Matthew Bunte: Yeah. What’s really interesting about this procedure, this deep vein materialization procedure, is the very first one that was ever done that we’re aware of was published in the Journal of Surgery, Gynecology and Obstetrics in January of 1912. And they did an anastomosis at the common femoral artery, common femoral vein. Fast-forward about 40 years, in 1951, I think, there was a case series of nine CLTI patients, all of them got amputated. There was an attempt to kind of revascularize and anastomosis proximally at the common femoral artery, common femoral vein.
And it wasn’t until Dr. Lengua from South America started to do this procedure and go a little farther, did about 60 arterializations. About two-thirds of them were successful, which interestingly is about the rate we’re now getting with this new technique we just published. And so he really helped pioneer this concept of arterializing the distal veins of the foot and that potentially being an option. So that experience, Dr. Lengua’s experience really is what helped develop this percutaneous treatment option that lymph flow offers of this distal deep venous arterialization.
