top of page

BackTable / VI / Article

The Advantages of Auryon Laser Atherectomy in Calcified Arteries

Author Sara Stewart covers The Advantages of Auryon Laser Atherectomy in Calcified Arteries on BackTable VI

Sara Stewart • Jun 30, 2024 • 34 hits

Though laser atherectomy has been around for many years as a treatment option for peripheral artery disease, there was little research on its microscopic effect on calcium morphology until recently. New research by Dr. John Rundback has successfully used micro-CT to analyze calcium patterns in peripheral artery disease at a microscopic level, evaluating the effectiveness of the Auryon laser atherectomy device. This article provides an overview of two of Dr. Rundback’s groundbreaking studies: his initial B-Laser™ (Auryon) IDE study and his recent micro-CT cadaveric study. Learn how the findings from these studies can inform atherectomy device selection via calcium morphology on IVUS.

This article features transcripts for the BackTable Podcast. We’ve provided the highlight reel here, and you can listen to the full podcast below.

The BackTable Brief

• Dr. Rundback's initial IDE study of the B-Laser™ (Auryon) found similar clinical outcomes between patients with varying degrees of calcium, leading to further investigation into the laser's unique effects on calcium disruption.

• The subsequent cadaveric study used micro-CT to examine the Auryon laser atherectomy's impact on medial calcium, demonstrating that the laser effectively fractured medial artery calcification, offering promising results for calcified lesions.

• Findings from Dr. Rundback's research indicate that the Auryon laser atherectomy is particularly effective for disrupting challenging plate-like, circumferential calcium, suggesting a valuable role for this technology in treating complex cases of peripheral artery disease.

• While micro-CT provides detailed insights in a research setting, its limited clinical use means that clinicians rely on IVUS for imaging. For patients with significant calcium buildup, orbital atherectomy is commonly preferred based on IVUS imaging results, but Dr. Rundback’s work suggests that laser atherectomy may be at least equally viable.

The Advantages of Auryon Laser Atherectomy in Calcified Arteries

Table of Contents

(1) Insights from the B-LaserTM Atherectomy IDE Trial

(2) The Effects of Auryon Laser Atherectomy on Micro-CT

(3) Atherectomy Device Selection in Peripheral Artery Disease

Insights from the B-LaserTM Atherectomy IDE Trial

Before conducting his cadaveric laser atherectomy study with micro-CT, Dr. Rundback was the principal investigator in the B-LaserTM (Auryon) IDE study. The study aimed to evaluate the safety and efficacy of the B-LaserTM on patients with infrainguinal PAD. Results showed similar clinical outcomes between patients with moderate to severe calcium and those with lesser calcium, regardless of using drug-coated balloons post-atherectomy. This led to a deeper investigation into the laser's unique impact on calcium, prompting further preclinical studies supported by AngioDynamics.

[Dr. John Rundback]
Well, let me step back even before that, because the aha moment, maybe it occurred a year or two earlier. When we brought over the Eximo platform, which was the Israeli platform, which is now the Auryon laser, which was purchased by AngioDynamics, I had been the international and principal investigator for that IDE study. We had a fair amount of calcium in that study, I believe 40% of patients had moderate to severe calcium. We also had other kind of plaque morphologies. We noticed a couple of interesting things. First of all, in both the IDE study and the subsequent registry, some patients get a DCB after atherectomy and angioplasty, some didn't. Some patients had calcium, some didn't. Our observation when we interpreted the data that there didn't seem to be a whole lot of difference in clinical outcomes at six months and a year in terms of restenosis, and obviously events, in patients who had DCB or didn't, and patients who had moderate to severe calcium versus lesser degree of calcium. That was sort of an aha moment there. Are we using this laser in a way, maybe it's not specific to this particular laser, but we think it is, that is obtaining a different result than we would have anticipated with other modes of atherectomy?

That was the first aha moment. Now, the next remarkable thing is we went back to AngioDynamics and said, "This looks a little bit different. We need to do some preclinical work. Would you support that?"

[Dr. Sabeen Dhand]
It's a big ask.

[Dr. John Rundback]
Right. It's a big ask. That's always a little bit of an iffy proposition because in general, especially when you've had fairly favorable results, companies are a little hesitant to open up the lid a little bit, look under the trunk and–

[Dr. Sabeen Dhand]
They already know it's working. Let's not rough the feathers, basically.

Listen to the Full Podcast

MicroCT for PAD: What You Need to Know with Dr. John Rundback on the BackTable VI Podcast)
Ep 353 MicroCT for PAD: What You Need to Know with Dr. John Rundback
00:00 / 01:04

Earn CME

BackTable CMEfy button

Stay Up To Date

Follow:

Subscribe:

Sign Up:

The Effects of Auryon Laser Atherectomy on Micro-CT

From the results of the B-LaserTM (Auryon) IDE study came the idea for a cadaveric study with micro-CT to more closely analyze the Auryon atherectomy’s effect on medial calcium. Dr. Rundback explains that traditional CT has been a barrier to infrapopliteal PAD treatment because the arteries, though densely calcified, feel pliable externally. The cadaveric study successfully utilized micro-CT to handle and analyze these specimens, revealing that laser atherectomy can effectively treat calcified arteries and fracture medial calcium buildup. This approach holds promise for improving peripheral artery disease interventions.

[Dr. John Rundback]
Right. You don't want to maybe find something you didn't anticipate finding. They were really open to it, doing this and focus first on the idea of CT, because I'm sure you know, CT to me is the biggest barrier we have for infrapopliteal work. I have a joke. I say, you ever play rock, paper, scissors? Always choose rock.

[Dr. Sabeen Dhand]
It's a good one. It's a good choice. I always do that too.

[Dr. John Rundback]
Because as far as I could tell, rock always wins. So that was the milieu we wanted. To look at these arteries, it's interesting. First of all, they're very densely calcified specimens. You don't have that picture to show, and yet when you feel them, they don't feel like rigid tubes.

[Dr. Sabeen Dhand]
Sure. Sure. They don't feel like hard rock.

[Dr. John Rundback]

No. These are still arteries that are bending and folding and pliable. Although this is a lot of calcium, it doesn't externally affect the feel and the visual aspects, the optics of the artery, nor is it so rigid that just manipulating it cracked, as we said before, the calcium. So we were able to handle these specimens, lay them down and put them into the gel mold as we wanted to. That was interesting. No difficulty cannulating them with sheets on each end and tying them down. Obviously this is ex vivo. We would occasionally have some holes in the artery, which we had to sort of close up.

[Dr. Sabeen Dhand]
Okay. Little bleeders, little perforations.

[Dr. John Rundback]
It wasn't always the neatest experiment.

[Dr. Sabeen Dhand]
That's funny.

[Dr. John Rundback]
All in all, it worked very well. I think we were able to achieve our objectives. The other thing is, which is interesting, and this sort of a little bit of background is, Jihad Mustapha, he does extravascular ultrasound when he does his interventions. He has the good fortune, and some labs now do, of having an-- what do they call them? Interventional sonographer who's in the room watching this.

He had already had an observation that areas of calcium that were not that pulsatile when de novo, after he had gone and done atherectomy, were now pulsatile. He restored the compliance of the blood vessel. That's a little interesting because if you go back to basic science and physiology, that compliance of the vessel is directly related with production of nitrous oxide, vasodilatory factor, and anti-restenotic cytokines. There may be something just restoring the normal pulsatility and compliance of vessel in addition to somehow disrupting calcium to allow maximal luminal expansion.

Atherectomy Device Selection in Peripheral Artery Disease

Despite its benefits in research, micro-CT is not commonly used in clinical settings. As a result, clinicians must rely on other imaging modalities, such as IVUS, to guide their choice of atherectomy device for patients with peripheral artery disease. For significant calcium buildup, indicated by complete shadowing on IVUS, orbital atherectomy is often a preferred choice. However, findings from Dr. John Rundback's study suggest that the Auryon laser atherectomy may be particularly effective for disrupting plate-like, circumferential calcium.

[Dr. Sabeen Dhand]
Interesting.

I want to kind of pull it back. Probably no one has access to a micro-CT in their lab. Guarantee no one who's listening on this podcast has that or can see this plate-like calcification, medial, et cetera. Coming back to a practical standpoint, one is, with your findings of using a laser and other atherectomy devices, do you need to make a difference between intimal and medial and decide on your atherectomy device based on that? To do that, would you use IVUS or what would you do?

[Dr. John Rundback]

This is not an IVUS podcast, but we use IVUS in almost every case. Obviously a lot of reasons to use IVUS, make sure you're intraluminal, first of all. Atherectomy is a very different value proposition if you're sub-intimal, although we do use it in selected cases if there's calcium to get an idea obviously of vessel size and determine calcium.

Absolutely. When we see patients who have a lot of calcium, now we're looking at calcium dedicated technologies, which might be orbital atherectomy or now based upon this data, it might be more Auryon or other forms of laser atherectomy. If we see a lot of intimal calcium and really just complete shadowing, like you said, now we're leaning more towards orbital atherectomy. Now we have to get that inner surface before we can ever have an impact. If we see deeper calcium, deep to the internal elastic lamina, that gray ring on IVUS, now those are ideal cases based upon our findings for this technology. What you said is exactly right. We did this study with an idea to finding a clinical implication. This wasn't just done in isolation.

The idea was how can we learn from this so that we could guide clinicians on what to do? That's exactly the point that we came up with. If you have a patient and you see this calcium and it's not predominantly intimal and circumferential calcium, that's a case that you want to make sure you go super slow so you deliver energy. B, you want to make sure you make a pass at least 60 millijoules so that you can treat that appropriately.

[Dr. Sabeen Dhand]
A follow-up question to that too, why not just turn up the energy all the way? What does the energy go up to above 60? Can it go to 80?

[Dr. John Rundback]
No, there's two settings, 50 and 60. The reason that we don't necessarily do that is that the unique thing about the Auryon laser, since it's a very, very short pulse width and it's delivering these bursts of energy is that it's actually on a fraction of the time. Because it's on a fraction of the time, there's a large amount of time for tissue cooling. So the predominant effect is photo-mechanical and not photo-thermal, because as you know, thermal injury has its own long-term impact on producing restenosis. That's why we generally start low. By starting low, you're avoiding thermal injury. If you need to then you can go a little bit higher, certainly if you want to maybe get a larger lumen, but when you have calcium, you need to use the 60.

[Dr. Sabeen Dhand]
Again, I'm more familiar with the Spectranetics/Phillips laser where that had different settings as two different numbers where you can go up to even 80. Now, how does that compare? Is it still doing the jackhammer effect you're talking about and delivering energy in a photo-mechanical way to the medial and maybe even other adventitial or intimal layers?

[Dr. John Rundback]
Yes, obviously you have the frequency and the fluence that you're adjusting on the Phillips laser. The fluence is basically the size of the micro bubble at the end, and the frequency is going to be the mechanical effect of that. Either way, the pulse width on that laser is more in the order of 100, or even more, I think it's even more than that, nanoseconds. Whereas the pulse width on the Auryon laser is 10 nanoseconds.

There's going to be much, much more thermal delivery with that. Yes, you can dial it up, but by dialing it up, you're actually getting a lot of thermal energy delivered into the vessel wall, in theory. Again, a lot of this is kind of in theory. It's hard to test this specifically. You can't put a little temperature probe, but–

[Dr. Sabeen Dhand]
You can put it in your bottle with the gel.

[Dr. John Rundback]
Right, exactly.

[Dr. Sabeen Dhand]
Give it a try. No, it's very interesting. I'll be honest, in my practice, where we have a ton of tibial disease, a ton of calcium, I've always been under the impression of, if I'm doing atherectomy, my first thing is CSI. I think CSI, orbital atherectomy is my go-to because I have been so disappointed with other technologies with heavy calcium in the tibials. It's a tough thing. I've always asked my friends, Kumar, all these other people, Mark, Mike Watts, do you guys use laser and stuff? They'll say yes, and then I'll try the laser that I'm familiar with, and it just didn't work. That's why I always go back to orbital atherectomy.

Podcast Contributors

Dr. John Rundback discusses MicroCT for PAD: What You Need to Know on the BackTable 353 Podcast

Dr. John Rundback

Dr. John Rundback is a practicing Vascular Interventional Radiologist at AIVS LLP in the New York City area.

Dr. Sabeen Dhand discusses MicroCT for PAD: What You Need to Know on the BackTable 353 Podcast

Dr. Sabeen Dhand

Dr. Sabeen Dhand is a practicing interventional radiologist with PIH Health in Los Angeles.

Cite This Podcast

BackTable, LLC (Producer). (2023, August 7). Ep. 353 – MicroCT for PAD: What You Need to Know [Audio podcast]. Retrieved from https://www.backtable.com

Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.

backtable-earn-free-cme.jpg
backtable-plus-vi-cta.jpg

Podcasts

MicroCT for PAD: What You Need to Know with Dr. John Rundback on the BackTable VI Podcast)
Advanced Radial to Peripheral Interventions with Dr. Sameh Sayfo on the BackTable VI Podcast)
Transitioning from Academia to Private OBL Practice with Dr. Jafar Golzarian on the BackTable VI Podcast)
The 'Woundosome' Concept with Dr. Lorenzo Patrone on the BackTable VI Podcast)
Percutaneous Transmural Arterial Bypass: Updates on Technique & Data with Dr. Peter Soukas on the BackTable VI Podcast)
Below the Ankle Expertise: Distal Pedal Access with Dr. Marta Lobato on the BackTable VI Podcast)

Articles

The Role of Micro-CT in Peripheral Artery Disease (PAD)

The Role of Micro-CT in Peripheral Artery Disease (PAD)

The Role of Serration Angioplasty in Peripheral Artery Disease

The Role of Serration Angioplasty in Peripheral Artery Disease

The Serranator Balloon: Tips for Successful Operation

The Serranator Balloon: Tips for Successful Operation

Tools & Techniques in Iliofemoral Stenting

Tools & Techniques in Iliofemoral Stenting

Topics

Get in touch!

We want to hear from you. Let us know if you’re interested in partnering with BackTable as a Podcast guest, a sponsor, or as a member of the BackTable Team.

Select which show(s) you would like to subscribe to:

Thanks! Message sent.

bottom of page