Craig Walker, MD, and S. Jay Mathews, MD, share an overview of laser science and present case examples for how they treat advanced peripheral arterial disease using Philips laser atherectomy.
so honored to be joined tonight by dr craig walker who I believe needs no introduction, but he is the founder of the Cardiovascular Institute of the South, as well as the founder and chairman of the new Cardiovascular Horizons Conference or N. C. B. H. Um and dr jay Matthews, who's also an interventional cardiologist in bradenton florida manatee Memorial Hospital and he specializes in complex coronary procedure of portable interventions as well as some structural heart. So very honored to be joined by both of them tonight and to learn from them about how they treat advanced material disease. These are other thank you. And I want to turn it over to dr walker who will walk you through his thoughts on on laser science. Thank you Devon. I'm really pleased to be with all of you tonight to discuss basically the physics and the science behind the use of three oh eight nanometer, excimer laser if I may have the next slide. Ah And I think it's important to understand what laser is laser is a form of electromagnetic radiation. Uh and the name for it was coined by none other than Albert Einstein. Right at the turn of the 20th century, it stands for light amplification by stimulated emission of radiation. So this is electromagnetic radiation. It is a form of light and but it has certain characteristics, it is coherent and have only one wavelength next lot. Now. In order to create laser light, we need three things. We need a medium. The medium that we use will ultimately determine what wavelength of laser light we can create. We need a means by which to excite this medium. In the case of the laser, the 308 nanometer excimer laser used by spectrum eggs and phillips. This is high voltage. And then we need optics. This is a chamber consisting of gases that have out uh mirrors on either end, so that when the light is created, when laser light is created, it bounces around and then at some point there's an aperture to allow the light to escape one command so that we can utilize the light. Next slide. Now the lazing medium, which we use is a mixture of xenon gas and hydrogen chloride. And when this is bombarded with extraordinarily high voltage, we form a molecules in on chloride. That's this continues to be bombarded with high voltage. What happens is an electron jumps in orbit and ultimately, by the laws of physics, this electron will always fall back to its resting orbit and when it falls back to its resting orbit, it emits a photon or a packet of light. This case, it emits excimer laser with a wavelength of 308 nm. Now, if we wish to change that wavelength we would change a medium. Next slide please. Now the word excimer is a contraction of two words excited and I'm er and this is a mixture of an inert gas and a halogen. So if indeed we had zen in fluoride, that would also be an excimer laser. And that excimer laser is the one which is used in um in ophthalmological surgical procedures. Before there is more than one excimer laser. And if we want to be scientifically correct, we should refer to the xenon chloride laser as 38 nanometer excimer laser. Then we know certainly a wavelength of light utilized next now. Why this wavelength and why not others? Well, if we look at the spectrum of light, the shortest wavelengths of visible light is violet and the longest wavelength is is red now beyond red, yet much longer uh than red is infrared and before violet, much shorter wavelength is ultraviolet. And this is very important because the short wavelength light really does not emit heat uh in an inert substance. If I were to apply 308 nanometer excimer energy for instance, to a test tube of sally. And there would be no heat created at all. That is not true for infrared lasers. Now, why this laser and why not Others will certainly, I've just mentioned one factor. It is cool. But what we want to look at is absorption depth into tissues. When we're using a laser, we wanted to have a very shallow penetration depth and we want to be able to carefully sculpt away tissues. We must look at absorption mechanism. If we look at light. When light interacts with matter, it is either absorbed, reflected, refracted uh are dispersed. And in this case we would want a laser light which is absorbed so that it can affect the tissues that we're treating. We want to look at the absorption mechanism and finally absorption losses. We know that this laser energy can travel very well over fiber optics. And so there is some energy loss from the module into the fiber optic fibre. Once laser energy enters the fiber optic fibre, it's very efficiently transported to the tip of the laser and therefore can treat atherosclerotic plaque and thrombosis and the other tissues that we want to treat. Next slide, please. Now, absorption depth is very important because we don't want to burn through the side of a vessel. So we want a very shallow depth of absorption and through eight nanometer excimer laser has that. We know that the fiber optics can carry this energy with very little loss, so therefore there's little absorption losses. And we know that light energy is absorbed, transmitted or reflected. Arterial plaque does absorb this very well from us even better perhaps of the components of uh arterial obstruction, the most resistant tissue to treat or actually uh things which are densely calcified. However raw laser will indeed affect calcium as well and we'll cut through bone. And certainly some of the new changes have allowed us to more effectively treat calcium as well. Next slide please. Now, when we look at this energy which is created, we first get a light pulse and this kind of blade mixed morphology is at a molecular level, a photochemical effect by disrupting molecular bonds. This is very important because this really does not result in large debris. This would result in debris, which would require electron microscopes frankly to see. It is not typically obstructive. The second thing that happens is there's an acoustic shock wave that is created by the creation of excimer laser energy. Now, this is important as this may uh impact rigid materials and change vessel compliance. So this may indeed take very structurally hard calcification structures and help to soften those as we go through. And then finally we have a cavity ation bubble which occurs and this capitation bubble is larger than the catheter tip and this can help to pre dilate lesions. It can also help us in removing things such as the next slide, please. So if we look at this on a time frame, we can see that there is a light pulse and this is absorbed by materials and this breaks bonds at the molecular level. Secondly, we have this acoustic shockwaves shown here on the right. This expands out in all directions and this impacts rigid materials, helping to to perhaps fracture some sub minimal or medial calcium. And then we have a cavity ation bubble and that's the third component. This gravitation bubble expands and collapses. It is directly related to the amount of energy that we're applying with laser. Next slide please. Now, if we look at laser laser, any form of energy applied into a biological system could indeed cause heat. If we use grinding materials because of friction, we get heat. If we use laser a little bit higher on the electromagnetic spectrum is a microwave energy. And of course what happens is as tissues absorb this energy, there can be some heat in this case vibrational energy, a microwave energy. However, The laser is only firing even at its highest frequency, which is 80 pulses per second. It's only foreign. Uh 4% of the time and it is off 96% of the time. So even when there is no flush, just the heat sink of the tissues results in the fact that uh temperatures at the catheter tip Does not exceed even 42° and even less than this, of course, if we have flush at room temperature or were using lesser uh frequency rates. Next slide please. Now we can modulate too. Energy factors. When we use laser influence is a measure of energy density. And so this is millie jewels from millimeter square. Some people measure it. Uh indifferent measurements, but nonetheless, it's it's a volumetric measure of energy at the tip. I look at higher, fluent as my means of creating a larger channel or creating a bigger vapor bubble. When I'm trying to treat from us, Rate is the same as frequency and this is not the frequency of the light. The light will always be 308 nm. This is the frequency of how many pulses were giving a second. The more pulses we give, uh the better we can impact rigid tissues. And so I use higher frequencies when I'm dealing with tissues. Next slide. So here we can see the difference of fluids as we can see on the left and we look at the capitation bubble. It's it's much smaller. A lesser frequency than it is. Affluence. Excuse me. Than it is at the higher influence. Next slide please. Same energy pulse. Now, one of the things that is really paramount if one is going to use laser and get the kind of results that you want, you really don't want to advance the layers or more than a millimeter per second, ideally what we're trying to get is photochemical ablation of plaque and other tissues which are obstructing our luminous. And this is best accomplished if we maintain a speed of no more than a millimeter a second. Uh and this allows us to really take advantage not just a photo ablation but of the acoustic in gravitation bubbles to achieve a much larger lumen. Next slide Now we have different types of laser products. We have the turbo power, which is really the newest of the laser devices in this has an eccentric wire loom and very densely packed calcification fibers And it has a motor which drives and rotates the distal 1/3 of the catheters. This comes available in a two and a 2.3 iteration. This allows us because of this eccentric rotation to negate dead space and to also make bigger channels. We have the turbo Elite catheters. These have fairly closely pat fibers and you can see that these fit over a wire. These can be over the wire or they can be rapid exchange Models. The turbo elites, all turbo elites and triple power catheters can accept frequencies of up to 80 and all can accept fluency Of up to six. Except that .9 Turbo. We can go all the way up to eight and the 2.5 can only go 45. And then we have the series of coronary catheters as well. Next slide please. Now the turbo power is really one of the newer catheters out. I've really been very impressed with uh its ability to help us better treat patients. Because this device, which comes in a two and a 2.3 millimeter option, has its eccentric wire limit. And we can direct the laser. But above and beyond that if we spin the laser, we can negate dead space because the area around the wire cladding, the area shown here as silver. If you would in the area down near the wire luminous dead space. But if we can rotate this tip, we can negate that dead space. And I found cases where other laser fibers, even tiny fibers would not cross dense calcium. And yet turbo power would easily a blade its way through those areas, achieving large luminous. And then if we see the turbo elite on the other side comes Available in sizes from .9 to 2.5. Again, this treats at the tip and I think this is very important when we speak of laser as many forms of a threat to me, tree away from the tip. Therefore, there's the potential for uh symbolic debris occurring with the inert part of some catheter having the first cross a lesion here, we're treating from the very tip and this allows us to cross in the bulk. The other thing that the turbo elite may allow is for us to utilize step by step or actually lead with the laser to help us cross lesions that we may not otherwise be able to cross um with wires along. And we have certainly a lot of clinical data on this device. Next slide please. Now, perhaps the area that I think that laser is the most, the most information is of the excite trial Where laser was utilized to treat instantly snow scene without equivocation. This randomized controlled trial gave level one data that laser was superior to balloon angioplasty uh, in terms of both safety and efficacy and we're certainly uh starting to see uh more and more adoption of this. But in my opinion, this was very strong data and it's the first randomized controlled data for any athlete wrecked me device clearly demonstrating uh superiority over balloon angioplasty. And I think this is again very important data. Next slide. So there are key takeaways from this talk when you use laser, it's very important to understand what you're using. Uh This is not a grinder, it's not a cutter. This is something which has to be advanced very slowly, no more than a millimeter a second. You should use saline flush. This helps to clear blood and contrast from the field, allowing the laser energy to directly interact with the material that you're trying to oblate. You should set proper expectations for multiple morphology is in multiple vessel applications. For instance, if I see calcium, I'm going immediately to a device such as a turbo power type device. When I see the rhombus, I'm typically going to be careful to try to avoid embolization and if I'm trying to clean out the large graft with rhombus, I'm going to use high influence. Very important, understand they've been more than 200 peer reviewed studies of excimer laser use. Now I use them a laser. I think it is absolutely mandatory to have this intriguing instant restenosis because it helps to remove the tissue in the cloth and then we can follow that with other treatment. But we use it certainly for all forms of infra inguinal stenosis, and we use it to cross total inclusions where a wire alone may not cross again, I found this very useful in certain cases of instant restenosis where typically we can cross with a wire, but occasionally because of fractures are the problems of wire will not cross laser will actually often get you across that area of inclusion because the cross sectional area of the laser is greater than the interest. Urschel pattern of the stent X slide. Now, it's very important also to understand why you do not want to laser in contrast. Typically, if you can advance the slide on the left, please. This is a study I did in my lab and here you see a laser and ceiling and nothing happens uh as you can see on the right first laser in contrast and I exploded the tube. But this is going to be laser and half contrast on the right of the screen. If you would activate that, please, by clicking. If you would activate. There we go, you can activate that here. You can see that this is at lesser energy levels and only half contrast. And you can see that there's a profound capitation bubble occurring here. This can cause the sections and perforations. Therefore, it's very important to typically try to achieve a contrast free field when one is applying laser energy. Next slide. Okay. And I think at this point we'll go over to dr Matthews. All right, thanks a lot devon if you could uh turn off your screen sharing, thank you very much. And I'm gonna show some case examples here as well too. There was a question craig regarding uh symbolic protection with laser. I'll touch on that a little bit too. And I think uh I don't know if you have any thoughts about that real quick before we get started. Yeah, I do I don't I think that of all forms of a thyroidectomy laser symbolizes the least. That's been my experience in the past. And one of the things that I like about laser, I don't routinely use um symbolic protection, but I do use it in certain cases just not so much because of laser, but because of the substrate I'm dealing with, I may use it in limb salvage where there's only one outflow vessel and I'm very worried that anything going down may cause problems short of that. I don't typically use routinely um distant protection with laser and I agree with that as well to um I think again you got to know what you run off is. I think all a threat to me devices have the potential for embolization. Again, if there's a lot of promise there, if there's heavy calcium you're doing a long length run, it does certainly increase the risk. However, the risk does tend to be fairly low, especially proper technique. I want to just go through a bunch of different case examples. Craig's also got some cases as well to and will try to go through some of these quickly kind of show you the breath of laser applications with the various devices. And, you know, one of the classic examples of horses, instant restenosis. This is a patient who has a rougher for five wound frank gangrene in the left foot. He's got left lower extremity inclusion. So this patient unfortunately had been previously extended by another operator fairly extensively with super a stent so extensive preparing starting from the top, going over the bottom and you can see here is gonna flush osteo inclusion Um and appropriately placed location. However you can see we've got no flow and this set of super extends extends all the way below into the P- three segment. Uh and we don't really see much in terms of runoff. So uh, this was extremely dense and hieratic. You know, when superior stents, they opened up their great, but when they go down with that high metal, the tissue ratio, uh you know, sometimes you have something that's similar to Iraq and uh you know this is one of those situations where I had to use combination of a very aggressive crossing catheter plus a quick cross craig will also talk a little about step by step as well. Too late. But you can do a step by step approach with laser without a wire to cross through some of these uh conclusions as well to to try to break that hard proximal cap. In this particular situation, I did use to a term of power with rotation and then a one for Tripoli laser below as well too. So appropriately sized lasers are important, especially in this type of situation. So within that S. F. A. The to a term of power with rotation worked beautifully. And then below when we get into the distal vessel, especially into the teepee trunk section, I wanted to size down to the 1.4 triple elite as well. And then afterwards we use angie sculpt and used a drug coated balloon. My goal here was to try to avoid stenting. So you can see this is kind of what it looked like after the injury, sculpt and stellar ex drug coated balloon with a very nice result here. Uh laser really is the preferred uh correct me tool for this type of lesion. The other devices that are out there to you run the risk especially with these centric cutters and want to actually getting stuck in the stent struts. There have been multiple cases reported of devices getting embedded in requiring surgery for extraction. So laser, it's really impossible to do that. So I think it's the safest choice and obviously indicated as well. Two for instant restenosis. And you can see here below the one for laser with P. T. A. We did use a DCB within the pop but down below just P. To itself. And you can see we were able to restore the single bustle run off to the foot. The patient did well with this. I'd like to show a calcium example as well. To this is a much older gentleman still smoking aggressive uh disease. Again another roughly from five patients. And ultrasound suggests extensive left lower extremity disease. And in this case you can see the calcium. Just on the fluoroscope on the right hand picture, you can see just chunks of council going up and down. So in this particular case uh it was somewhat difficult to cross through. I decided to use symbolic protection just because I was worried a little bit about the the amount of calcium there. Now some people would say well laser how effective is it in calcium but term of power with that s centric fiber pack I found is very effective in calcium. And it creates uh fragmentation of this calcium as well. Now most of the time with proper technique you don't really worry about embolization that scenario. But you know there still can be cases if you have heavy calcium, especially intimate calcium as well, it may be appropriate to use symbolic protection in this particular case I did. And you can see here I'm slowly going through with continuous rotation back and forth essentially. And what this allows you to do is to create uh circumferential effect with uh acoustic power. Now what interesting is that you can laser forwards and you can laser backwards and that's what I typically do with the rotation. Also it can bounce off some of these calcium rocks that are in the S. F. A. Making it easier to cross as well. Sometimes a straight catheter may not move as well as the one that's rotating. And I would say that we did increasing uh frequency uh at the pretty much the same high energy level going back and forth until we were all the way up to 60 slash 80. So uh this uh this patient did quite well a note. Uh I did a laser. I'm sorry. Rather ibis to show what I did just after developing. So this is just uh service without any ballooning. And you can see here we've done a pretty good job of debunking this thing. There are still some areas that need yielding. And that's why uh I decided to bring in the annual sculpt. And you can see here in this next picture here is a 200 million Rand. You sculpt and what you see here, this is not a area of stenosis or recoil. It's just balloon rap and use the longer and sculpt balloons especially over up and over type technique. You can see uh some rotation and then this uh this double balloon. It's just important that uh you make sure that you get the uniform deflation. If this happens again, it's not really a big problem. Uh A lot of times will go away with a repeat inflation and it's really of no typical clinical significance. Uh And then afterwards we went ahead and scented uh due to some areas intersection. Uh And then you can see we have a very nice result here as well. Two or three bouts of runoff below. Here's another example as well too, with a combination of fibrous tissue and calcium. This is a patient that's Rutherford for you might note that the patient does not have a refund. A there's a big collateral coming from above which is from the hypo uh and then multiple collaterals going downstream uh from this hippo to uh maintain profusion below. Um This patient you can certainly consider doing surgery on. But again, we were asked to do an endovascular approach for this particular case. You can see here, we use to a term of power and across through this inclusion and use the android sculpt with a drug called blue. Now, my goal here is not the stent because I do want to leave a surgical option in place. Um Common federal already, intervention of course, remains a somewhat controversial topic, but sometimes it's necessary. And in this particular case, um I decided to go ahead and use ideas to help us out afterwards because I wasn't sure exactly what I was looking at. And you can see here this is the ibis image on the right hand side. I'm gonna zip through this a little bit quickly. You can see we have a bunch of e centric plaque and then area of focal dissection. This is actually within the F. A. And then the remainder of the common Federal itself actually looked pretty good. So there's an area where it bulges out uh down below, which is where there's a section. But up in this area really looked okay. And so I was able to get away with the DCP result there. I ended up putting in a couple of uh tax here as well to in the S. F. A. And I was able to establish the common Federal without having to use any type of stent in that area. And we thought this is a fairly reasonable result for this particular patient. And she did well with improvement of her symptoms significantly. Now, I want to talk a little about combination therapy and this is something that we do a fair amount of as well to. You saw a case earlier where you spoke truth to power, Trouble elite. And again, it's all about sizing appropriately the patient in this particular patient with a flush inclusion above. We chose to do a retrograde approach from the foot. So you can see here, we're coming up through the posters of artery. Uh, and you can see that there's extensive disease uh in the uh to prepare the trunk as well. And then also another uh P. One inclusion. Uh and then a uh brief island of Peyton C. Within the S. F. A. Before a total sf inclusion as well. So you can see here crossing through with a crossing catheter, I decided first to treat the below the knee disease With the One for Tripoli 60, 60, 60, 60, 80. Some people ask, well, how do you get adequate flush? There's a couple of techniques that you can do. Sometimes you can actually hook A to E. To the back end of the catheter, Uh, and uh, and use a 014 wire. Sometimes that will work to offer some sailing uh, to go to the tip of the Catheter most of the time if you have flow from above, You can also drip from above as well. But this is a way to potentially deliver local energy. Sometimes it's not possible, especially using some of the smaller laser fibers, but in this situation ended up getting a very nice result down below. And then I had to address what was going on above. So you can see here across. Superheated pretty easily. But I went ahead and perform diverse because I wanted to know where did I cross through. And there was actually a proximal uh, section of the S. F. A. That was quite, you know, was wide open. You can see there's extensive fiber optic plaque here. Were intra Luminal in this particular section as we go up through here. So this is the whole area that I'm going to end up treating. However, as I go up to the section of patents, you can see that my wire veers Submersible and so where I'm popping in above here too. There's a long segment of pete meself a but I'm still some internal before I return and intra luminously. So that's not an ideal place that I wanted to extend into. I'd rather try to maintain the proximal patent see. So I opted to pull that wire back and take a different approach. And this particular scenario used the Pioneer plus from below actually. And this is a uh Davis catholic, combined with a reentry needle made by Philips that allows me to identify exactly where my reconstitution point is and pop back into the true looming. So I was able to enter lower into the S. F. A. This allowed us to potentially save a larger area of of uh the S. F. A. From having to get scaffold. So I went ahead again using two oh turbo power with with rotation, the forwards and backwards. Five oh by 200 sculpt and ultimately ended up using a. D. S. Within the mid two distal S. F. A. Approximately. I decided to go ahead and take a look here too and what was interesting, I thought that everything looked beautiful, but this is the point why it's important sometimes do I this afterwards and see what you did. And you can see here, things look decent within the stent in segment below. What you saw was papa chill artery. But look right here. So you can see here. Good, good to the stent. And then just above the stent. Look at that. There's a big flap and there's actually intramural hematoma. And so this is actually shutting down the vessel. If I had stopped and my initial anja looked great, that's because we're not doing an orthogonal view, You're not seeing that actually the luminous being compromised. So that's why it was important in this situation to go ahead and address this area of dissection, which I took care of with some tax tents above. Now, down below, I also play some additional tax sense across the top of the lottery as well too. And ended up with a fairly nice result. There was an area of focal recoil that we addressed with a short drug. Eluting stent as well too. And this is what our final result looks like. You can see uh there's scaffold down below uh, but just some focal tax sense above look quite nice. And we were happy with a fairly good to vessel run off to the foot patient did very well with us. One last case I'd like to show is a below the knee example. This is a patient actually really roughly for five. Not rather for six with uh heal wounds, gangrene. By definition, if it's a rough for six, it's really not salvage. So it's really a high level Russian for five patients. So you can see here that we've got a single vessel via the perennial But included 80 MPG. And I wanted to get in line flow from the foot. So you can see here that this is what we're going to look like to. We have a parallel collateral. But I wanted to get more flow to this volcano branch and also to the planter pt, which feeds the forefoot as well. So what I did in this situation was go ahead. And I stuck at the bottom of the foot under ultrasound, there was a large planter pd target and we put a place at four or five star slender. You can potentially do the sheath list as well too. But since I knew I wanted the laser from this way, I wanted to use the 45 and the 45 will accommodate up to a 17 laser quite nicely. So in this particular situation, we went with the 14 triple elite. So it's easy crossing from below. Uh as we had an ambiguous cap from above, it was going preventable, but from below we had a very nice uh time crossing through. This was a more favourable approach. Again, using the one for troll elite at 60, 40, 60, 60 and 60 80 fluids and frequency. We treated the entire segment and then performed angioplasty of the entire poster di bari. There was a focal dissection due to where I had tried. Coming from above that did not respond to uh initial stenting. This predated my attack B T K U. S. And in this particular situation, I used a focal coronary drug with intent to address this dissection and this patient did very well. The hill gangrene was able to be addressed with the agreement and the patient did well and finally healed. So with that I'm going to stop sharing my screen and switch over to craig here. J those are great cases. And I think a great point made about using I've as I use Ivers routinely. It just shows us so much more. Then we see um when when we just simply perform angiography, I just have a couple cases that I had sent in before. I don't have quite the beautiful IOS images to go with them. But these were just cases of what indeed we can achieve when we use laser devin. Would you advance these please? So this was a patient with fairly extensive gangrenous changes of the foot and multiple field distal bypass surgical procedures. And you can see here that really all of the infra pop little vessels were totally occluded. And this is just a case that two of these vessels, the posterior tibial and the anterior tibial. We actually used initially just to get started. Step by step technique to get approximately Um 2-3 mm beyond the area of total inclusion. And then step able to lead through the rest of this and perform de bulking and balloon angioplasty. And this just shows you that often we can completely reconstruct these infra pop little vessels. I have had an extensive experience with Laser below the knee and of course, going all the way back to the early lacey trial that was done in the 80s. This was shown to have great benefit, long term, next slide please. So these are just a couple examples of what we can do. This was a patient who did have plantar ulcers of the foot. We can see that there's a patent pharyngeal. It had a high grade lesion, very, very poor feeling of the foot. Um We perhaps could have tried to get through this collateral, but with poor likelihood. And so here you can see again, coming from above, uh we were able to recapitalize the posterior tibial and achieve very nice feeling of the foot. And this patient again had complete healing. Next slide. Please. This was a patient who uh was just, believe it or not, a severe Claude if it did not have ulcers and didn't have a little bit superficial femoral disease, but really couldn't walk but a few feet and it had a small ulcer. That was nothing that was really that remarkable. But there was an area of skin that was not great and patients wanted something done. And so we actually went in just simply cleaned up these vessels. We achieved all three open and the patient had amazing symptomatic improvement with this. This is a bit controversial treating below the knee for things other than just true them salvage. That's usually where we use it. But we have had occasional cases where uh it did make the night and day difference for our patients. And uh I found this to be pretty safe in these patients. Next slide. Please. This was a case of a patient who had multiple surgeries, had this up a little artery, aneurysm and had multiple surgeries for apartment artery aneurysm and these failed. And um what we can see here is I was able to perform a little step by step at the popular till this had been dried elsewhere. Uh the lesion had been attempted. The surgeons felt there was no surgical option anymore. They had been in in this man many times and so we lead and we got down to about the knee joint and then we lead with a wire and you can see we were able to establish in lines flowing to the perennial. And again this patient had them salvage. Next slide. This was balloon alone. And here we can see the patient again, another infra pop little uh image. I apologize. I can't see my image to the right right now. But you can see post treatment we had established but the patient and all vessels included right at the knee. And we saw no feeling for pop little vessels. First after laser we've established flow into the foot, next slide and then finally another patient with no real named in from a political vessels, uh fluid stopped right below the stent that we see in the distal superficial cerebral artery. We came down here and hit this with a laser and ballooned and were able to establish nice to vessel flow into the foot next lot. So, you know, I think laser is a tool that allows us to do a lot of things. Think terrible power uh has allowed us to to deal with calcium much more effectively. J and I were discussing this before and I think there are many reasons it does. It clearly um creates orthogonal displacement of friction and allows us to get through things we could not before, and it clearly negates dead space. And so it not only makes a bigger channel, but I think it makes them more effective channel by crossing and J pointed out sort of bouncing around through the calcium but also getting through these areas where other catheters may get hung up. So with that we're more than happy to answer any questions anyone may have. So craig, I got the Q. And a window open up here. I guess we'll just try to going through some of these questions. So one of the first questions is how effective is laser and tibial C. T. O. S. I think uh from my perspective I love using laser material ceos. I find it to be highly effective. Um Certainly there are multiple devices that people can use. Um phillips also has the phoenix device as well too. But laser has been my mainstay for tibial C. T. O. S for a long time. I don't know what you think. Uh Yeah well I think I showed you a bunch of typical vessels and uh it's my go to in that area. I think it's a very effective tool there particularly in these patients who any symbolic phenomenon might result in losing their legs. Most of these people are legs are really big trouble when we start right. Um And then uh I think uh there was one raised hand there too as well. Uh if you can take that uh take them off me, you can ask a question. The audience. Did you guys hear me? Yeah, we can hear you. Yeah. Hi, this is uh Suhail khan from Salt Lake City, dr walker. I'm here to listen to two of my favorite people that walker being our mentor and it's one of those who like this field 20 years ago where I'm sure people were like, question him, what the heck he's doing? But he changed the field as we know it. And me and jay people like us, we are thankful to him about doing that dr walker. I have a question as you know um the venus ulcers um are five times more common than arterial ulcers. And lately the last 4 to 5 years we are getting to know a little more about venus disease And now we have two FDA approved by your stands for for that. But I'm going to share one case with you and get you apart. And it was like a year ago and there's a patient came in with venous ulcers and of course had multiple bein operations. Um and and then I checked his brilliant man, he had previous 10, many years ago. Now that was completely occluded, something I've advocated pretty strongly for uh for a area of research central Maine inclusions and things like that to uh I guess there's a question is the market going to be there also are the device is big enough as well too. And this also applies to the question that's out there regarding user laser for filter retrieval. I've done it but I really can't talk about it because it's not approved. Um and uh but certainly there's an interest offline. We can certainly discuss these types of things. But this is an area of research and study and hopefully something that they're going to try to pursue indication for as well. Thank you guys. Thank you. Um So there was another question regarding uh preferred settings for turbo power in calcium craig. I'll let you kind of mention what you can do for that. Yeah, I actually go to high frequency. I think frequency is our friend when we were dealing with dense calcium. And I think rotation is our friend when we're dealing with dense calcium. It does allow you to feel your way through the boulders. But keep in mind that laser is doing something. We historically didn't really acknowledge. This acoustic shock wave that is being created by the delays or this acoustic wave is indeed softening those tissues. And so I can show you case after case with turbo power, where other lasers did not cross in the past, where it crossed easily. We're often following laser treatment balloons would not expand where the balloon then expands easily. I think jay you're very nice case looking at the ultrasound where even in dense this trophy calcium, he showed you that he made a really big luminous with just laser before doing anything else. And I think some of that is the laser impact. I think some of that is the softening of the calcium and the use of this capitation bubble as a pre dilation kind of phenomenon. So I think laser is effective in calcium. If we look at excimer pure excimer laser in the past, not in a catheter which is clad by metal cladding, it would actually cut through bone. So I do think it has impact. I just think we have areas of dead space that stopped it from really having a great impact. Also keep in mind, calcium comes in two forms. It comes in that which is intra Luminal, which we can easily reach. And it comes in more commonly medial and that's more difficult to reach that we're not really reaching that we're hoping to impact with this acoustic shock wave. And that's the more common form of calcium before. So there's another question. Um And I think this is a good one from coming from dr Sherman, my twitter friend, um what's the ideal fiber? A ratio of fiber to our generation for B. T. K. And I'll say I typically uh half size it. So I tend to use a lot of the one for uh laser for for tibial vessels, assuming the century tibial is around a three millimeter vessel of greater. Um uh rarely have. I used the 17 And then, you know, I'm usually the 170.9 is more for distal vessels. Sometimes I'll even use it in the pedal second as well. Craig any thoughts about that? Yeah, I use the two thirds uh catheter the vessel size. Except except in areas where there is very acute angles, so where the anterior tibial perforated inter odysseus membrane and then goes downward. We have two right angle, bends there, so right as it originates. And then as it turns down to run towards the door, some of the foot. And the reason for that is laser energy goes straight and the catheters bending. And therefore, if we make multiple passes, we're shaving the purposes of those areas. So in those cases I would downsize. The other time, I would downsize is if I thought I'd I'd crossed mostly in a true lumet, but perhaps in a small area sub intimately, I would treat that vessel. And the reason I would is the area I would be thinking I would make be making the big impact is the area I've treated. True alumina lee. But you know, I would, there may be a small inter posed area of sub animal crossing. And in that case I would want to decrease the size. But if I thought I had a truly global crossing throughout in a straight segment, I would try to size 2/3 of the vessel. I'll say that in the above the knee segment the S. F. A. Want not to, I'm a little more aggressive I think with sizing and especially because you know that the architecture of the vessel is quite large. And uh, so I have no problems using to a trip of power. Even with rotation of the sub internal segment, I've had really good results with that. Okay, I see the question from, from dr Cornwell on describing step by step technique. And so when laser came out, this was really something that was pushed very hard, jean Carlo B amino described it. I think now we have even more potential use for that now. So um this is using laser to cross things don't. One area where I use this all the time is if I can't cross uh instant restenosis, particularly if I can get a wire barely into a stent, I'm then certain that I'm inside the stent, then I'll simply lead with the laser because the interest Urschel pattern of the stent is smaller than the cross sectional area of the laser. Therefore it keeps you in the lumen and you would be amazed how many cases this crosses. Beautiful at that point, when your wire has come Absolutely to stop otherwise. Now, the other form of step by step is when we get down to a cap, which is really hard and we just can't blast through it or because the geometry is perhaps bad. And the idea is to advance your Catherine to that point. Turn energy settings to as low as you can get. Turn the energy on and advance the catheter very minimum. You're just trying to soften that plaque to really allow your wire to get in and hopefully cross the leisure. You're not trying to cross everything with just the laser. Typically, you're trying to oblate that proximal cap and allow your wife to take a path going down. And so this sometimes can be very, very helpful in crossing total inclusions in today's world of spectacular guide wires. I don't think we're using as much step by step to try to cross the entire lesion um anymore because we certainly have great steer ability in our liars and great penetrates. But the step by step, particularly in instant are particularly just to get a wire started when it's going nowhere. When you when you've reached a brick at that point, it still is very useful because it will soften that cap. And by the way, if you're doing this in the legs turn your energy is too low and carefully monitor pain. If the patient feels pain back off public land somewhere, you should not. Mhm. So I guess there's somebody asking about when you would use orbital after ectomy over laser. Any thoughts on that, correct? Yeah, I think orbital a thyroidectomy plays a real role in in uh Luminal, in Luminal calcium. Certainly that's an area. An orbital. A thyroidectomy comes in much longer catheter lance. And and I'm doing a fair number of cases. Transredes early at this point and it's really uh in those cases the only option if I want to reach. But I think that it has a real role in uh an intra Luminal calcium for sure. And I think is a good tool there where I would not use it is instant restenosis. Okay. I don't think it's device to be used there or if I think there's active from us. I think I think laser is a superior tool in those two circumstances. Yeah, I would I would echo all of those sentiments as well too. I mean, it's a good tool uh definitely I think for tibial vessels as well to it can be very useful as well. But again, had great results with laser in those types of situations as well. I guess that would segue right into this comment regarding laser thrombin ectomy versus using something like realistic or mechanical section for clot. Um, I can tell you that and uh my world if I know that I'm in France thank from this, I typically tend to use more aspiration devices first prior to laser ring Because I don't like to make my life hard. I think the technique necessary to address a large robotic segment requires really meticulous, slow advancement, less than 100 per second to really oblate throughout this. So if I know that there's a bunch of clot there too, I will use some other type of device first, typically before lazy. Yeah, I agree with that. To j I will tell you where I think laser and clot matters. As in very old conclusions. There's almost always some thrombosis. So we talk about one month to month cloth. That's one thing when we speak about clot that may have been present in something for really a long period of time. Then that's where I think the fact that laser does work on this old promise. I think it does play a big role there because typically even our aspiration devices there that this has become tissue, which is really wrapped up and it's very difficult to pull out with any form of aspiration. It's indistinguishable from fiber optic clock at that point. That's right. Yeah. There's a there's a question regarding preventing laser complications. Um and you know, it's an interesting one because I think there are so few laser complications in general. You mentioned one that can happen I guess when you go someplace you're not supposed to go. One thing that I've seen sometimes, especially with the larger laser fibers, especially terrible power is if I do a lot of uh of, of lazing and uh, you know, especially at high settings and what not to. Um I found that sometimes some patients will have increased soreness and I think that's from the vibration effects as well too. I think there's some halo effects that going to happen. Not so much thermal damage or things like that too. But really just, I think there's a lot of acoustic effects that happen from the turbo power device. I've typically managed that with, with, with just minimal pain control afterwards. It typically resolves itself. Craig any any thoughts on that. Yeah. The one time I've seen people experience pain is in really small stints where, you know, uh, often a poorly expanded previous stint, small vessel. And sometimes if we go in those at very high energy, uh, those cases didn't do well after the whole experience, convenient. So we give them or members moment. Obviously you want to avoid this. That's that's very important. I really want to really what Yeah. Change it to get Section to have a problem with laser. That's typically not laser. That's typically because someone lose 70 ladies were way too fast. Most people are not following the rules, media access in advance and safety you follow that will you're not gonna have a lot of uh huh. As I say, boy, good people. Of course. Yeah. Um, I think that that's great. Um, I think, uh, there's also a question regarding, um, flushing and I think, uh, there's two ways to flush I think with, with laser one you can do from, uh, from your manifold via the sheath and also flushing through the catheter itself. We I kind of mentioned an example where, um, if you didn't have a sheath above to flush through or from below and you're not gonna get adequate sailing flush. Sometimes you can flush with the tip of the catheter. Um So typically in order to do that, you have to be able to downsize the guide wire and be able to get enough of sailing to come to the tip of the catheter. I tend to do more uh flushing from uh the sheath itself. Uh and I find that to be fairly effective. Craig any any thoughts on that. I agree with both of those things. You just said, that's how I do it as well. Okay. Um it's a comment regarding laser and papa till vessels. This has been a hotbed topic, just like common former arteries. Uh, I think uh, you know, is that a space? Actually somebody posted a question on twitter regarding, I think it was uh out of Mount Sinai. Uh They asked the question, what would you do with this Pop little high grade lesion? Uh and how would you treat it? And uh and you know some people are saying doing endarterectomy went to but you know we've shown some cases of effect of pop little ceos and high grade lesions being treated with laser. Um I think it works. I like turbo power for it and using sculpting DcP. Um Any thoughts of that? Yeah, actually public to lesions all the time. Okay. And you know I think it's controversial to treat pop bottles if there's they're not included and there's a nice otherwise segment you destroy that segment. Most of the pop bottles I'm treating are totally occluded. And I don't know Any surgeon that bypasses two and included pop a little segment. And so I don't have a lot of a fear treating a pop cortical segment that's totally occluded. Obviously if I don't want to ever take away a surgical option of patients. But I certainly treat a lot of popular teals and often those are sent to me by surgeons because there are no targets for them uh to work. So I use this in the Pop little segment a lot. Found it to be very helpful. And in fact, um if I'm going to treat the Pop little segment, I like the concept of first treating with a laser and then following that with a drug coated balloon so that I don't leave any metal implant in play. And perhaps in the future if something is required surgically there is still uh that capability of applying a graph. I would I would add a service that way. You can size your balloon quite effectively and avoid the sections, especially in that segment. Agree with that. Yeah. In fact I use Ivascyn almost all my cases now. Yeah. That that's you can't get any better than that really. So there's a question regarding specific lesions for using the trouble family more effectively. And I guess also tossing the question regarding when to use phoenix. Mm. Um, so, uh, craig any thoughts on that. Yeah. So to me, I was one of the investigators for phoenix as well. In the past, it takes me a little more time to set up the phoenix and it does laser. I think it's an effective after ectomy tool. I used it. I had reasonable results with it, but in a high volume center I found that the laser was a little bit less expensive to use and a little quicker. So I don't have anything against the phoenix after directory devices just to have a lot in favor of the uh in favor of the laser, frankly, in terms of my use. But occasionally I will use phoenix and some of the infra popular till lesions where I have some calcium and it's a smaller vessel and I'm, you know, I can't use something like a turbo power that rotates through and I find phoenix to be pretty effective in those cases. How about you? Yeah, I mean, I I agree with that. I mean the only time I'm using phoenix that I have, I have a hospital which doesn't have laser. And so I'll bring phoenix there too. So there's no capital in that particular scenario. There are some office space labs and a SCS as well too. If you don't have laser available to be nice to, you know, you can bring phoenix in those scenarios. I've had some good results with the two to phoenix below the knee in the S. F. A. Um I still really like laser a lot and uh so, you know, it still remains my main stay as well and largely, you know, in the S. F. A. I'm using terrible power. Um not using as much trouble lead nowadays just because I really like the rotation and I like the efficacy. You know, you're getting a much, getting a lot more Luminal gain with a smaller laser fiber. Yeah, I assume there's a question. Do you ever see heat damage to the wall of a vessel? You know, I don't, we don't certainly measure heat damage, but I will tell you uh that even with just a catheter bear catheter and uh Out any flush, we don't see temperature changes rise above 42°C.. Our body temperatures 37 C. So that's really not whole lot of extra temperature here. This is not something that's boiling a vessel, like some of the old uh laser balloons and things that were used in the past, when, when tissue samples were taken in the past. There was no clear evidence of any heat damage. But certainly in clinical practice, I don't know how we would otherwise measure that, but I think it's highly unlikely, particularly if you couple with flush because with no flush in the situation where you going to get the highest amount of heat, you're still never going to get above 42 degrees. It's not a great. And if you couple that with room temperature flush, I think you're probably uh maybe even staying below typical temperatures. So I just don't think that's a real concern in this circumstance. Yeah. And the tissue effects are really just in front of the laser fiber itself to so, you know, we're not getting uh I mean you're the effects that are the halo effects are from the capitation. So it's not really a thermal injury. Um It's more of a photo acoustic effect. So uh there's another question regarding uh level of evidence and outcome for using laser and C. T. O. S. And uh and to use uh D. P. I don't know if that means a drug eluting balloon or what that is specifically. There was a comment regarding essentially using laser prize are uh I mean uh the C. T. O. S. Uh multiple studies have shown laser uh being used in long length lesions, some of which are CTO S. Uh two socket, three type lesions. So there's plenty of evidence there is suggests uh laser affect me works within those types of lesions. Um I don't know craig if you have any thoughts on that. No, I I agree with what you just said. For sure. Yeah. Uh Oh, somebody's asking about a quarry cto trial for step by step. Uh I don't know when that's going to have happen if anyone's going to fund that study. Uh I've certainly done it, but that's uh you have to be really sure exactly where you're going. If you can do something like that, it's obviously considerably more challenging. I've seen uh dr Lombardi do it with the two later in the corner before, to which I would strongly not recommend. Let's see here. Um What's the largest vessel diver that you feel you could treat with laser? That's a good question. Um I'll say, you know, with a 23 turbo power, I mean, you can easily treat a seven millimeter vessel and even a potentially above maybe even an eight with halo effects. Uh, to a term of power for me, I use in six million vessels all day long without a problem. And even some seven millimeter vessels as well. But to three is probably better suited for that pregnancy thoughts. Uh, Yes. 2, 3 Turbo power. When we looked at Ive us in the past fairly routinely made a five millimeter channel by ideas. And so, uh, yeah, yeah. Follow that to blend. So, I think pretty effective. Pre effective treatment. Yeah. So, you know, the acute Luminal gain that you get with laser is not like I think really is important because there's a halo effect you get. I mean, it turns that tissue to almost like a gel, really. You get that chemical change within the tissue. So what I find is that makes it so much easier when you take a scoring balloon in there afterwards to to get a much larger looming. If you tried without lazing first, you'll find you have a lot more recoil. So I guess D. P. Was regarding a symbolic protection. So yeah, I mean, again, we kind of think we address that a little bit too. I think that uh I were both fairly selective. I think anabolic protection used uh symbolic protection is expensive. It's not it's not cheap. Uh And you want to be selective and it's used. However, I would never discourage anybody from using it if if necessary because it can certainly make it a bad day if you have to go chase after clock or in bali. I agree with that. But you know, it's it's also not only expensive, it's not without its own inherent risks, right? I mean, we can enter those distal tissues is retreating long segments. The filter itself may migrate often. We don't fully protect when we're treating on the long area because of that migration. So, you know, I'm not against district protection. I'm an advocate of distal protection, but most cases that I treat with laser, I don't use distant protection. I do use this to protection with most forms of a threat to me. Okay. And I do think there's a difference there. That that remains something that has to be proved. But in my clinical practice, I think this is a difference in the size of the debris and the amount of debris and the significance of the debris. And so I don't use it very often here. I use this in high I use this protection and I'm using laser only when there's very, very poor run off. And I think there's very new promise. Yeah, I think that's I think that's fair. That's very reasonable. I agree with that too. And again with other devices as well to where I'm less confident, I'm definitely using more distant protection there too. I don't do distant protection very often with laser. The other reason why I don't do it as much now too is I do a lot of aspiration mechanical aspiration from back to me as well too. And I feel very comfortable with that but fortunately it's not necessary most of the time. So it gives me a certain level of comfort, especially since I'm in the hospital. Sure there's a question here, any experience using turbo and iliac. So let's start busting go. No, a threat to me tool is approved in Iliac artery treatment. So let's start with that. And so if one is to use that, it's truly 100% off label. And uh, and that's because stints in the iliac have historically done fairly well. And yeah acquiring about how do you get back to using laser after not having used it for more than two years? Certainly uh if you wanna visit either JR or us, that's certainly possible. Even in the covid era. You know we have an O. B. L. And Lafayette that we we can certainly work with someone and let them see these are cases and get a feel for this. Hospitals are still right now a little difficult to get around with golden even for people to observe. But as long as one is feeling okay and coming in I think at some point we have to get back to normal lives and uh it's about time to do that. So we would certainly help you with that. And I honestly, you know, I'll speak to my own laser experience. And I started using laser about 10 years ago. And the way I learned to do laser was when I joined uh the current group I'm in right now, I started as in the O. B. L. I asked the question well, what a threat to the devices you have? We have laser. And I said, well I've never used laser before and they're like, well you're gonna learn right now, so much I learned after the first case. So it's uh I think that if you've used it before, it's like riding a bike. So I think but if you need help, we're certainly going to be talking about doing some live cases virtually as well too with phillips and uh uh hopefully we'll be able to do some of our live prospering and also our our case observations as well. And then we have one other question from my buddy sal khan and he says, when will we see us again at N C. B. H. And so here I will just tell you, not soon enough. We we would we really miss seeing everybody and and having the educational forum that we all enjoy being able to all interact with each other. And obviously Covid's made that difficult between the physical separation that's required and the travel restrictions and groups not being able to travel. It's pretty difficult this year were we're trying to do this in a digital series, but we're going to try to get back to this because we do think it's important to have dialogue between peers and we're committed to getting that together again in the future. Yeah. I hope to get craig out to the sea beach florida meeting in uh in March. So we'll see how it goes. Well. You know, we've actually run through all of our Q&A. That people have submitted and I know we're 15 minutes past where we where we thought we might end. Um, so I wanted to say, thank you both so much for for going past time answering so many questions and providing so many great cases. For example, um, this has just been fabulous. I've been getting text messages and, you know, notes from people already about how helpful this was. So thank you so much to both of you and any last comments are, um, to the crowd and we can we can end up for the night. This is great. Yeah. This was a lot of fun guys for, for me, I certainly enjoyed it. Got to speak to friends and certainly this is this is a very nice break from the other covid stuff that we've been getting to do. Absolutely, wonderful. Great. Well, thank you so much again. This is fantastic. We'll see you on the screen again soon and maybe in person really after that. Mm.