Podcast Transcript: Pedal Acceleration Time for Limb Salvage

[Mary Costantino]
So, I have a couple of ways in mind that we use it, but let's talk. Why don't you tell the audience how you and I use this on a typical day in the OBL.

[Jill Sommerset]
So, we scan all of our patients in Dr. Costantino's lab in an outpatient setting, and we do pedal acceleration time on every single arterial patient. It can be for a foot pain, for claudication and, of course, for tissue loss and rest pain. This is just an extension of the arterial duplex. We can do a limited arterial duplex, and that's billable for PAT. It's the 93926 CPT code. So, it's all billable. So, we use PAT in the preoperative ultrasound, and then when she does her case, I like to mark on the patient's foot where the vessel is if it's right next to a lute. We'll do a PAT right before the patient rolls into the cath lab. Then I know exactly where to place my probe when she's delivering therapy.

We're oftentimes the only ones in the cath lab to jump up and down and be so excited when we see that dramatic change, especially in the antegrade access. It is instant. Once she does atherectomy and does balloon angioplasty, that PAT changes on the table, and then we use it postoperatively as well for wound surveillance.

[Mary Costantino]
Yeah. So, we just had a case last week where the guy had an occluded femoral artery, an occluded PTFE, fem-pop graft, and an occluded fem-tib venous graft. Started having grafts in 1984, had surgical groins bilaterally, and reported a seven-hour surgery for some leg aneurysm from his previous surgeries that "didn't work". So, we knew his groins were a nightmare. He had scars all over his legs.

Jill mapped him. He had a profunda that had elevated velocities, and then branches going into his AT. His contralateral groin was heavily calcified, about 60%-70%, bulky calcification, so it's unfavorable. He was on Plavix for coronary stents and he was obese with a large panis. So, Jill hands me that ultrasound. So, I did this radially, and that's not the interesting part because I think a lot of us could do that. I just went down into the profunda, atherectomized the profunda, ballooned the profunda, and what I used Jill for was she went on down to that foot and he had a class IV PAT. I didn't know if I was making any difference in this foot.

After I pushed the intervention as far as I could from the profunda, she looked at the PAT, and it was a class III, which is not exactly where we want it, but much improved. So, I knew that I had actually reestablished flow down to his foot. He has an ulcer and a pretty ischemic foot.

Then the decision was: do I need to do an attempt at any tibial revascularization? You had occluded AT and PT and you just had a single peroneal. So, complex case, and knowing that I had improved the flow to the foot with just the atherectomy and angioplasty, the peroneal allowed me to stop then to see how he was doing over the next couple of days. That was really critical information because had I gone down to this guy's AT and PT, I don't know that he had enough flow in them to really keep them open if I had put a sheath in. I think I would have given myself just about 15 minutes to do the case because I was worried about occluding one of his tibials.

So, really critical information that allowed me to make a decision I was pretty confident about. The other way I used Jill in that case was that he did have a small aneurysm in the common femoral artery right before the profunda, and I didn't want to atherectomize in the aneurysm. So, I had the wire down the profunda, and I was envisioning the orbital atherectomy device flying around in the aneurysm. So, I wanted to start right at the origin of the calcification, and I had marked it with IVIS, but he had moved and all this. I mean, we're talking millimeters of difference. So, I had her ultrasound over the orch and the profunda. I lined up the atherectomy device exactly where the calcium started, and I knew exactly how far I had to go. So, it was a completely visualized atherectomy, which helped because of the proximal aneurysm.

So, you can gain a lot of confidence in these procedures when you have a tech that can actually direct you. I think anytime we can actually see what we're doing and have some less subjective and more objective data, that's valuable.

[Jill Sommerset]
So, one of the common questions, too, is do you have a dedicated vascular technologist in the cath lab, and my answer is yes because not only can we monitor PAT, but we can also be really valuable for just what you spoke about, which is extravascular ultrasound, where a new set of eyes that we can get right at the CTO cap with wires or catheters or help place balloons or stents extravascular. So, I think that in itself is an extra tool that can be really helpful.

[Mary Costantino]
Yeah. Can you describe how you do that? Can you describe just the flow of the case? Let's say I have a CTO and it's on a Jill Day, which, of course, they always will be. Describe your role in the cath lab. You don't just sit there the whole time. I mean, you're out working and coming in and out. So, describe for the audience how the flow of that work goes.

[Jill Sommerset]
So, in my opinion, we always have to plan. I did the preoperative duplex ultrasound prior to the case, so I should know that patient's perfusion and occlusions, and CTO caps better than you. So, when I do the preop marking, I mark on the patient's leg where the CTO caps are, so I know the length of occlusion and I know exactly where to place my probe during the case. I also mark on the patient's foot, so I know where if I'm going to look at their arcuate artery, their dorsal metatarsal artery or the lateral plantar, I know exactly where to go.

So, then when the patient rolls in, I'm prepped and ready to go because the physician is always asking questions like, "Oh, how far do I have left to go?" or "Where's the cap?" or "What does this look like?" So, I always want to be two steps ahead of you and my time, as we know, well, time in the cath lab is precious. We have to be quick and efficient. So, as a vascular tech, we get into precarious positions to reach under the drape or go over at their folded prep, but while you're holding a balloon for a prolonged inflation, I'm going to get my ultrasound ready. I know exactly what the setting should be. Therefore, when the balloon is deflated and you pull it out, I can go straight to the patient's area that we need to look at and be really efficient. So, I think that there's a lot of prep that goes into these cases. So, the ultrasound tech can be very efficient.

[Mary Costantino]
Yeah. So, Jill will do the ultrasound of the patient preoperatively. Like she said, she knows the patient better than I do at that point. We also are doing a lot of patients with kidney disease as most of us doing a lot of PAD are. So, I have dilute contrast. I'm usually trying to use between 20 and 30 cc of contrast at most. So, these big beautiful runs that I use to get in the hospital when you power inject through the pigtail within the aorta. In the aorta, you get these beautiful images. They just don't happen because I'm trying to use a dilute metacontrast.

So, I can sometimes see the distal reconstituted vessels and sometimes not, but it actually doesn't matter. So, I just reduce the contrast dose between IVIS. Jill, I actually have done full CTOs with under 5 cc of contrast, and that's pretty incredible. We love to do that. So, Jill will usually be outside of the lab, and I'll be working away, and she'll be doing stuff out there.

I anticipate I'm getting the sheath up and over, going antegrade. I usually like to go antegrade, getting the lay of the land, figuring out what I want to do. If I anticipate I'm going to need Jill, I'll have my nurse or somebody go out and get here, and it takes her I would say under five minutes--probably under three. The machines are in the room. The machine is positioned. It's turned on, and the patient's name is inputted in there. The patient's marked. She knows exactly where she's going.

She just comes in. I don't think she keeps lead on, but she just gets her lead on, cap and mask and everything. She gets sterile and pops around and starts ultrasounding. That takes I would say under two minutes. So, we have no delay. Doing this adds zero delay. In fact, it saves a ton of time, contrast and runs.

So, if I have a CTO, I'll get positioned right in that cap. Of course, I'll try the old school way. I'll try to open it just through angio, but if this thing is heavily calcified, which I know because we've talked about it before. Maybe it's got a big calcified cap, but the rest of it is soft versus a 10 cm heavily calcified just pile of rocks segment versus all soft.

So, I'll give a little college try, try to poke a wire through there, but if it doesn't go or it's budding or it's going into that horrible little collateral that is coming off right where the cap is, I'm already calling for Jill. That allows me to position my catheter right up against the cap, and it allows me to do what I call really dangerous things. I'll say, "I'm about to do a really dangerous thing," but I don't really say that out loud because you can't say that out loud with an awake patient, but I'll get the backend. It's all stuff that we know how to do, but we don't like to do that much, like reversed ends.

I've used the reversed end of a weighted wire. Man, that thing is sharp as heck, but if I know I'm intraluminal and I'm right next to that cap and I'm watching, I can see where my catheter is, maybe I have a trailblazer down there, maybe I just have a regular Kumpe catheter, it doesn't matter. You got the catheter poked right in there and you can take that wire and you can shove really hard. I mean, I actually want to get a needle, that's my next thing because I just need to pop through that cap. If I know I'm intraluminal and I'm watching with ultrasound, you can be really aggressive.

We've gotten through some really incredible CTOs that way, and just the heavily calcified one we just march down. I'll ask Jill 14 times, "Am I intraluminal? Am I intraluminal? Am I intraluminal?" These are the cases where by angio the wire is making a little curvy twist and turn. You don't really know, "Am I going around the calcification or am I going subintimal or am I out of the vessel entirely?"

I like to say intraluminal because I do because I went subintimal once and have always regretted it. So, I like to say intraluminal. So, Jill will come in and out on those cases. When we're trying to get across a CTO, she's going to stay there the whole time, and I'm going to do basically the whole CTO by ultrasound.

The only time you can't do it is when that calcium shadows and we miss a centimeter. Sometimes you gotta watch that under angio. Then we always have the moment of celebration of when we actually get through, and then we move along with the rest of the case, and Jill's done until the PAT time. So, Jill, where is PAT being used? How are you seeing it used nationally and worldwide?