Atherectomy Devices for Peripheral Artery Disease

[Dr. Chris Beck]
I do want to set the scene as far as just broad strokes atherectomy. Tony, how do you think about [atherectomy] and how does it fit into your practice? By that I mean, who's getting atherectomy versus who's not getting atherectomy? You have a lot of choices with atherectomy. What's your thought process there?

[Dr. Tony Das]
That's a great question. For some people, atherectomy is a little bit more of a religion than a science. You believe in it. There may not be quite as much science as you'd like, but over time, we've continued to develop the science in this space. I think of atherectomy as an adjunctive tool. It rarely is a standalone. I think that there are lesions that really require a change in their overall response to balloon angioplasty or stenting, meaning we want to change their compliance. We use that as a broad term, but calcified lesions, we want to do something to make them less likely to dissect and have complications from balloon angioplasty. More fibrotic lesions or in-stent restenosis, we want to ablate some of that plaque. I think of it as an enabling tool. Depending on the type of lesion we're talking about, different forms of atherectomy seem to make more sense. We can talk a little bit about where we want to use certain types and where other types may be more helpful.

[Dr. Chris Beck]
For sure. One of the things I want to get at is atherectomy as an adjunct. In your practice, there's atherectomy plus. Let's exclude stenting for a second. Is it atherectomy plus POBO or atherectomy plus DCB? It depends on where? It depends on?

[Dr. Tony Das]
Yes. It depends a little bit on where, but I think that the DCB data has gotten so strong, and we finally put to bed the issue of whether there was a mortality signal for DCB. I think that's a topic that really sidetracked us for about two years. Now we understand that this is a safe technology. It's a durable technology. For me, typically, if the balloon sizes exist, especially in the above-the-knee territory, it's atherectomy plus drug-eluting balloon for the majority of the cases.

[Dr. Chris Beck]
I know that people can give whole lectures on this, but if you want to talk about the different choices that we have with atherectomy? Then, we'll zero in on where you like laser, and then for what reasons.

[Dr. Tony Das]
Just to put it in broad terms. Ablative technologies come in a couple of different flavors. There's rotational atherectomy. For those of us that are cardiologists, we used Rotablator even before there was any form of atherectomy for the lower extremity. Those were devices that had a diamond-tipped burr, and we used those to rotate it at 150,000, 160,000 RPMs. We used them for calcified lesions, and usually smaller vessels down into the tibialis, especially. Then came orbital atherectomy, which could give you a much larger lumen because the crown itself was rotating off-center, and so you could get larger lumens. We tend to use those in more calcified plaque as well. When there's more soft plaque, and there's a need for excising or blading, we use laser for in-stent restenosis.

We have proved that in a couple of different trials. Excisional atherectomy with eccentric plaque ablation like SilverHawk and the eccentric plaque, of those types, is how I think about it. Now, you can overlap those in different places. I think there's a need for some of those, but for the most part, if you have something that's fibrotic and soft, you tend not to want to use orbital. If you have things that are more fibrotic and hard, you might want to use that. I use lasers a lot. I use a laser to sort of change the compliance of the vessel, whether it's moderately calcified or fibrotic. In-stent restenosis, I almost exclusively use it there.

[Dr. Chris Beck]
We talked about broad strokes about different atherectomy devices and where and what types of lesions. What we didn't mention though is where you like each one. Maybe you divide it between above the knee and below the knee? This device if we're in smaller vessels, this device for bigger vessels, all things being equal? Is it more hard, soft discussion?

[Dr. Tony Das]
I think for me it's a little bit more above the knee and below the knee. It really does break back into hard and soft. Because if I got calcified, my tendency is to use something that's going to be more ablative, orbital atherectomy or even excisional atherectomy, but soft plaque, you can use pretty much anything there. What we've learned is the higher energies that laser atherectomy can afford us, even calcified plaque can be well suited for that. In the very small, very heavily calcified, we have the ability to use very high energies for laser, and that does change the compliance for those.

I think it's a little bit of both of those topics. Above the knee, I like using excisional atherectomy, and I also like to use orbital atherectomy. In the SFA, it can be a combination. Sometimes laser for instant resinosis or fibrotic tissue. Sometimes orbital atherectomy for more calcified but less fibrotic and soft. For in-stent, it is almost always laser. Then below the knee, you can use actually any one of those types. I tend to use a laser below the knee a fair amount because the lesions are pretty fibrotic. They're diffused. They're long. Oftentimes, they're calcified. Oftentimes, the only thing that will go through after a wire goes through is a laser because you don't have to change to a different type of wire. That's one big advantage of using something that doesn't require a unique wire to be able to deploy it.

[Dr. Chris Beck]
One of the things that stuck out to me was the adjunct treatments following atherectomy. You can correct me if I got this wrong, but roughly 25% DCBs afterwards. Does that mirror your practice, that a lot of its POBA follows atherectomy?

[Dr. Tony Das]
I don't know if this was broken down into above-the-knee and below-the-knee. I think that below-the-knee, we don't really have drug-eluting balloons that were available at that time and really don't even now have small drug-eluting balloons. If you look at the majority of these, 70-something-% were SFA and popliteal, and then about 25% or 30% were below the knee. That might have been a reason for some of this drug-eluting balloon use. The other thing that you may have noticed was how few of these patients actually got stents.

[Dr. Chris Beck]
Yes. My thought was that you're dealing with 10 centers, but maybe it was a no metal left behind approach or there was a concerted effort not to drop stents in this. Can you speak a little bit to that and laser's role in reducing barotrauma? I guess you're priming the vessel so that you're set up for less dissections once you actually get into the plasty portion of the procedure.

[Dr. Tony Das]
Yes, for sure. We've had a couple of trials over the years that have suggested that atherectomy in general and laser in specific can change the compliance of a vessel and also reduce the dissections. That's been shown in smaller studies and also over time. This proved that out a little bit in that there is a change to the compliance, probably a reduction in the mean balloon pressure required, the dissection rate, and the need for bailout stenting.

If you think about the bare metal stent use here, it was about 30%. I think that in general, what we see is that those that are proponents of atherectomy are also proponents against long segment stenting. That's not a hard and fast rule, but we definitely do see that when you use atherectomy, you tend to stent a little bit less. As we've gotten better tools for drug elution, I think that's continued to be probably more so than even in the last decade when we didn't have drug elution.