Retrograde Pedal Access Collaboration, Case Selection & Benefits

[Aaron Fritts]
Jim, what inspired you to first start trying pedal access, since it is a relatively newer technique? How did you learn it and how long did it take you before you felt comfortable?

[Jim Melton]
Over at the heart hospital, in 2013, I started sticking... if I was going to try to get through a CTO with an ulcer of an SFA or something, I got tired of not getting all the way through it or even being able to get past the proximal cap at all. I started sticking pedals with ultrasound guidance which, as you know, an interventional radiologist is the best, by far, no questions asked, period. And then, I mean, it was a skill I had to learn. I learned that and just stuck small needles and put a wire in, just so I could know I could do it. And then I said, "You know what? Let me try to get through this distal cap." And it just became very obvious, very quickly, that distal caps were so much softer than the proximal caps. A lot of times you just fly up with not a lot of product cost involved and you're able to save a bypass for another rainy day. I hardly ever stick a femoral or anything. That's from 2015 to present.

[Aaron Fritts]
Blake, was pedal access something that you learned in fellowship?

[Blake Parsons]
Sure. We did a lot of peripheral arterial work. We were fortunate, and this kind of goes back to me working with a vascular surgeon. At MCW you kind of worked hand-in-hand with the vascular surgery program there, so I had already had previous relations during fellowship between vascular surgery and interventional radiology. It was great. I would say we only did a handful of true retro-pedal, what people call TAMI cases. When we stuck tibial arteries it was because you were doing a Safari or something of that nature. I talked to Jim on the phone and he'd be bragging about how many retro-pedal cases he's doing and giving me a hard time. I was like, "Yeah, yeah, yeah." And then sure enough I got back and my practice was obviously slow at the beginning because trying to get the general public to understand what the heck an interventional radiologist is, is just part of the battle. So, I'd scrub in on cases with him and watch him do cases and, sure enough, he had a lot of retro-pedal access… I became a believer. And then my peripheral work increased over the past three years to 95% pedal. Now, there's still times I'll go integrate a femoral or SFA or up and over femoral if I know it's all below ankle or pedal loop or something like that where I want to get a better vantage point. But, for the most part, I also go retro-pedal from the foot.

[Aaron Fritts]
You talk about the Safari technique where you're still getting the access in the groin and in the foot. Would you mind clarifying that? Like, what you guys are doing? You're just solely getting access in the foot in the majority of the cases rather than getting dual access, right?

[Blake Parsons]
So we call it retro-pedal. I know the other name out there is TAMI. But, yes, we're talking single access within a distal tibial artery, PT or AT, sheath placed, and then all treatment is done from that sole tibial artery access. We're able to, like we said, accomplish that probably 95% of the time.

[Jim Melton]
I can tell you, my practice since we opened in '15, I haven't done one Safari. I think Blake's done a few just because of the extent of the disease or whatever.

[Blake Parsons]
Pretty rare.

[Aaron Fritts]
Let's go into how you guys approach a case. The majority of your cases are done by pedal access because you guys have the experience and the confidence. But, for somebody maybe newer... you guys get a lot of visitors that come through and watch you guys. Probably a common question is, what are the big contraindications to pedal access for you?

[Jim Melton]
It all starts with a really good clinical exam. That's what, again, what I was a little worried about with IR in general. But Blake, like I said, he came from a program that had that and it was really a pleasant surprise. A good clinical exam with a hand-held Doppler in the room, trying to figure out where these lesions are, is really the coolest thing that I do in clinic. I walk out and I know, pretty much, exactly where this lesion is. I also tell the docs that come and haven't done much pedal to go ahead and do a Duplex below the knee and visualize that the AT and PT is open. It makes them feel a little more comfortable sticking it. Or the interosseous, any of those three vessels. For your first 100 cases or so I would probably stay from one vessel run off. Blake and I both, still to this day, do that a little bit. If we think it's a one vessel run off case, we'll probably do a diagnostic first with either a little antegrade dilator or something like that, or an up and over small sheath and then decide whether we want to go primary pedal or not. Pretty rare on that but I think, at the end of the day, once you get some under your belt you feel more comfortable doing one vessel run off also. But, I think that just comes with a comfort level and experience as you go, going down the road. Pedal access is a really good way to recanalize a lot of vessels below the knee that are totally occluded with the selection of wires. I think at the end of the day, it's good for all three levels, below knee, obviously SFA's that have never dreamed of getting through, and then in foot disease also.

[Aaron Fritts]
And so, a lot of your patients are obviously CLI patients, guys with wounds. Anything in terms of like where the wounds located or do you worry about the access itself causing a wound?

[Jim Melton]
We like to try to identify the wound in these certain angiosomes for sure and try to figure out which vessel is important to healing that angiosome. That's part of that clinical exam deal on the front end. We try to cover up all the wounds on the prep, on the patient, and prep them out, if you will, and try to obviously stick away. We have over 2500 cases, CLI cases now for sure. I've never seen a wound caused by the perc stick that didn't heal or anything, to date. Distal AT, PT usually around the ankle--it just kind of depends whether we'll stick a DP more distal. Obviously, you're a little limited on your sheath size if you think there's more proximal disease. If I know and am pretty sure they've only got say a single vessel AT to the foot and I can't hear signal in their peroneal or their posterior, then I'll sometimes even just try sticking their occluded vessel and see how hard the plaque is. I'm not going to hurt it. So, I'll stick it and then it's kind of like a freebie. As long as I can get up through that, then I can get up and fix everything from there. We do have a pretty good idea before we ever step into the room. But, obviously, you've got to adjust on the fly some too.

[Aaron Fritts]
Getting started, I didn't want any bad outcomes so I was very particular in terms of my case selection. The best starter case for me, personally, was an obese patient with kind of a hostile groin and had an isolated tibial disease. It was relatively easy to get in, balloon angioplasty, give my post-injection and be done. And so, I think that, to me, was an ideal case to start out with. Do you guys have any suggestions on people who want to get started and maybe are a little bit hesitant?

[Jim Melton]
Yeah, you nailed it Aaron. I think, at the end of the day it’s those people that are just high risk to stick a groin. The radial's an option if you talk it through, but the radiation difference is drastic. I think that, at the end of the day, your ideal candidates for your first cases are two or three vessel run off and a total SFA with an ulcer. Those are your best ones to practice on. Below-the-knee disease is good. There's a lot of techniques that we try to teach when the docs come about up and over from PT to AT or AT to PT, or interosseous, either one. And so, we do those also without sticking the groin. The best cases and the most satisfying cases are the ones you can't get to from the top but you just fly through them from the bottom and you've healed up an ulcer. When you're a Critical Limb Ischemia Center of Excellence or that's what you want to be, you don't see a lot of those. But, at the end of the day, those are really good cases to practice and get a lot of confidence with.