Craig Walker, MD, and S.Jay Mathews, MD, in this previously recorded webinar discuss how they treat advanced peripheral arterial disease using 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. V. H. On Dr Jay Matthews, who's also an interventional cardiologists in Bradenton, Florida Manatee Memorial Hospital. And he specializes in complex coronary procedure of powerful interventions. I'm, well, some structural heart. So very honored to be joined by both of them tonight and learn from them about how they treat advanced performer tail disease. These are author. Thank you. And I want to turn it over to Dr Walker, who will walk you through his thoughts 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 38 nanometers. Excimer laser, if I may have the next slide. Ah, and I think it's important. Understand what laser is laser is a form of electromagnetic radiation on 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 of only one we've left Next slide. 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 300 nanometers excimer laser used by Spectrum eggs and Phillips, this is high voltage, and then we need optics. This is a chamber consisting of gasses that have, 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 bomb boarded with extraordinarily high voltage, we form a molecules in on chloride that's just 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 nanometers. 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 dime er, and this is a mixture of an inert gas and a halogen. So if indeed we had Zen on 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, uh, the shortest wavelength of visible light is violet and the longest wavelength is, uh 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 in an inert substance. If I want to apply 308 nanometers excimer energy, for instance, to a test tube of saline, 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 absorb reflected refracted, uh, or dispersed. And in this case, we would want ah, laser light, which is absorbed so that it can affect the tissues that were 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 fiber. Once laser energy enters the fiber optic fiber, it's very efficiently transported to the tip of the laser and therefore can treat after a sclerotic plaque and from us 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 nanometers, 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 arterial obstruction, the most resistant tissue to treat or actually things which are densely calcified. However, Raul laser will indeed affect calcium as well and will 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 shockwave that is created by the creation of excimer laser energy. Now, this is important is this may 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 predilections lesions. It can also help us in removing things such as 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 shockwave shown here on the right. This expands out in all directions. And this impacts rigid materials, helping to perhaps fractures, sub minimal or medial calcium. And then we have a cavity ation bubble. And that's the third component. This capitation bubble expands and collapses. It is directly related to the amount of energy that we're applying with the 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 used grinding materials because of friction, we get heat if we use laser A little bit higher on the electromagnetic spectrum is, uh, microwave energy. And of course, what happens is as tissues absorb this energy, there can be some heat in this case, vibrational energy of microwave energy. However, the laser is Onley firing even at its highest frequency, which is 80 pulses per second. It's on Lee firing Ah, 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 that the catheter tip does not exceed even 42 degrees and even less than this, Of course if we have flush at room temperature or we're 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 Milly jewels from millimeters square. Some people measure it, uh, in different measurements, but nonetheless, it's It's a volumetric, a 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 nanometers. This is the frequency of how maney pulses were giving a second. The more pulses we give, the better we can impact rigid tissues. And so I use higher frequencies when I'm dealing with calcification tissues. Next slot. So here we can see the difference of fluids as we can see on the left, and we look at the capitation bubble because it's much smaller Lester frequency than it is influence. Excuse me than it is at the higher Florence 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 advance of aliens or more than a millimeter per second. Ideally, what we're trying to get is photo chemical ablation of plaque and other tissues which obstructing our Lumen. 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 and gravitation bubbles to achieve a much larger Lumen next slide. Now we have different types of laser products. We have the triple power, which is really the newest of the laser devices, and this has an eccentric wire loom and very densely packed calcification fibers. And it has a motor which drives and rotates the distal one third of the catheters. This comes available in a 202.3 iteration. This allows us because of this eccentric rotation to negate dead space and toe also make bigger channels. We have the trouble elite catheters. These have fairly closely pat fibers, and you can see that these fit over where these could be over the wire or they could be rapid exchange models, the turbo elite, ultra terrible elites and triple power. Cather's can accept frequencies of up to 80 and all connects EPT, fluency of up to say, except the 0.9 triple. We can go all the way up to a and the 2.5 can only go 45 then we have the Siris of coronary catheters as well. Next slide, please. Now the turbo power is really one of the new Europe 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 this eccentric wire Lumet and we can direct the laser. But above and beyond that, if we spend the laser, we can negate dead space because the area around the wire cladding the area shown here as silver, if you would, and the area down near the wire. Lumen is 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 Lumen and then, if we see the turbo elite on the other side, comes available in sizes from 0.922 point five. Again, this treats at the tip, and I think this is very important. When we speak of laser, many forms of a threat to me treat away from the tip. Therefore, there is the potential for M bolic 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 boat. The other thing that the triple elite may allow is for us to utilize step by step. We're actually lead with the laser to help us cross lesions that we may not otherwise be able to cross with wires alone. And we have certainly ah 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 instant restenosis and without equivocation. This randomized controlled trials give 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 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 Athol wrecked me device, clearly demonstrating superior authority over balloon angioplasty. And I think this is again very important data next line. So they're key takeaways from this talk. When you use laser, it's very important. 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 in contrast from the field, allowing laser energy to directly interact with the material that you're trying to a blade. You should set proper expectations for multiple mythologies and 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 through, um, bust, 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 flu inst. Very important. Understand? They've been more than 200 peer review studies of excimer laser use. Now I use excimer laser. I think it is absolutely mandatory to have this in treating instant restenosis because it helps to remove the tissue in the clot and then we can follow that with other treatment. But we use it certainly for all forms of inference 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 or the problems of wire will not cross laser will actually often get you across that area of inclusion because a cross sectional area of the laser is greater than the interest Urschel pattern of stent Next 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 ah 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 in half contrast on the right of the screen. If you would activate that, please by clicking if you would activate, There we go. If 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. To there was a question Craig, regarding AM bolic 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 dio I don't I think that of all forms about directing me, laser implies, is 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, distal protection with laser, and I agree with that as well, too. I think again, you got to know what you run off is. I think all athletic me devices have the potential for embolization again if there's ah lot of thrombosis 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, essentially proper technique. I want to just go through a bunch of different case examples. Craig's also got some cases as well, too, and we'll 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 classics examples, of course, is instant restenosis. This is a patient who has a rougher for five wound Frank gangrene and left foot. He's got left lower extremity inclusion. So this patient, unfortunately, had been previously extended by another operator fairly extensively with super assistant. So, uh, extensive, Super starting from the top, going on the bottom and you could see here is gonna flush osteo inclusion. Um, appropriately placed location however you conceive got no flow. And this set of super extends extends all the way below into the P three segment on. We don't really see much in terms of run off. So, uh, this was extremely dense and fire erotic. You know, when superiors didn't stay, open it. They're great. But when they go down with that high metal, the tissue ratio, you know, sometimes you have something that's similar to Iraq. And you know, this is one of those situations where I had to use combination of ah, very aggressive crossing catheter, plus a quick cross. Craig, we'll also talk a little about step by step is well, too late. But you you could do, ah, step by step approach with laser without a wire to cross through some of these, uh, conclusions as well to to try toe brake that hard, proximal cap. In this particular situation, I did use to a term of power rotation and then a 14 Tripoli laser below us. 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 working beautifully and then below when we get into the distal vessel, especially into the teepee trunk section. I wanted to excise down to the 1.4 trouble elite as well. And then afterwards we use Angel's 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 angel sculpt and stellar extra coda balloon with a very nice results here, Uh, laser really is the preferred atthe wrecked me tool for this type of lesion. Three other devices that are out there to you run the risk, especially with these centric cutters and what not 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 to for instant restenosis. And you could see here below the one for laser with P. T. A. We did use a D. C B within the pop down below just pita itself. And you can see we were able to restore the single bustle run off to the foot when the patient did well with this, I'd like to show a calcium examples. Well to this is a much older gentleman still smoking aggressive of disease again another roughly from five patients and ultrasound suggest extensive left lower extremity disease. And in this case, you can see the calcium just on the fluoroscope. Be on the right hand picture. You can see just chunks of calcium going up and down. So in this particular case, uh, you know, it was somewhat difficult to cross through. I decided to use symbolic protection just because I was wearing a little bit about the amount of calcium there. Now some people would say, Well, laser, how effective is it in calcium but term of power with the east centric fiber pack. I found this 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 a circumferential effect with a acoustic power. Now, what's interesting is that you can laser Fords 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 air in the S F A. Making it easier to cross is well, sometimes a straight catheter may not move as well as one that's rotating on. I would say that we did increasing, uh, frequency attack. The pretty much the same high energy level going back and forth until we were all the up to 60 slash 80. So this, uh, this patient did quite well of note. I did. Ah, laser. I'm sorry. Rather IBIs to show what I did just after d bulking. So this is just a IBIs without any ballooning. And you could see here we've done a pretty good job of debunking this thing. There's still some areas that need yielding. And that's why I decided Thio bringing the endoscope and you can see here in this next picture here is a 200 military Angela 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 uniformed 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 on. Then, afterwards, we went ahead and scented, uh, due to some areas intersection on. Then you can see we have a very nice results here as well. Two or three about some runoff below. Here's another example is well to the combination of fiber optic tissue and calcium. This is a patient. That's right, the four. You might note that the patient does not have a profound A. There's a big collateral coming from above, which is from the hypo on, then multiple collaterals going downstream from this hypo Thio maintain profusion below, um, this patient, you could certainly consider doing surgery on, but again, we were asked to do an endovascular approach for this particular case. You can see here we're using to a term of power and across through this inclusion and use the handle sculpt with Drug of Blue. Now, my goal here is not to stent because I do want to leave a surgical option in place. Um, common thorough artery intervention, of course, remains a somewhat controversial topic. But sometimes it's necessary. And in this particular case, uh, 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 image on the right hand side. I'm gonna kinda zipped through this a little bit quickly. You can see we have a bunch of s centric plaque on then area focal dissection. This is actually within the S f a. On. Then the remainder of the common federal itself actually look pretty good. So there's an area where bulges out 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 D. C result there. I ended up putting in a couple, uh, tax here is well, too in the S f A. And I was able to salvage the common federal without having to use any type of stent in that area. And we thought this was a fairly reasonable result for this particular patient. And she did well with improvement over symptoms. Significantly. Now I want to talk a little bit about combination therapy, and this is something that we do a fair amount of as well. To you saw case earlier where you spoke terrible power, trouble elite. And again, it's all about sizing appropriate. The patient in this particular patient with the flush inclusion above, we chose to do a retrograde approach from the foot. So you can see here we're coming up through the poster to Marjorie on you could see that there's extensive disease in the super personal trunk as well. And then also another, uh, P one inclusion, Uh, and then a brief island of Peyton See, within the S f A before total S f A inclusion as well. So you can see here crossing through with crossing catheter, I decided first to treat the below the knee disease with a 14 turbo elite. 60 40 60 60 60 80. Some people ask, Well, how do you get adequate flushes a couple techniques that you could do. Sometimes you can actually hook a to e to the back end of the catheter onda and use a 14 wire. Sometimes that will work to offer some sailing 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 Europe rated pretty easily. But I went ahead to perform diverse because I wanted to know, where did I cross through? And there was actually a proximal section of the S f A. That was quite, you know, was wide open. You could see there's extensive fibroid ECLAC here. We're intra Luminal in this particular section as we go up through here. So this is the whole area that I'm gonna end up treating. However, as I go up to the section of paints, you could see that my wire veers sub instable. And so where I'm popping in above here, too. There's a long segment of Peyton S f A. But I'm still some intimate before I return intra Lumina Lee. So that's not an ideal place that I wanted to extend into. I'd rather trying to maintain that proximal Peyton sees. So, uh, I opted to pull that wire back and take a different approach. In this particular scenario, used the pioneer plus from below. Actually on this is a IBIs Catholic, combined with a reentry needle made by Philips that allows me toe identify exactly where my reconstitution point is and popped back into the true looming. So I was able to enter lower into the S f A. This allowed us to potentially save Ah, a larger area of of of the S F A from having to get scaffold. So went ahead again, using 20 turbo power with with rotation forwards and backwards 50 by 200 angel sculpture and ultimately ended up using a D s with in the mid to distill s f A approximately I decided 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, you know, decent. Within the stenting segment below. What you saw was pop little artery. But look right here so you can see here good for the 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 stents above now down below. I also play some additional tax sense across the property 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 there's scaffold down below. Uh, but just some focal tax since about look quite nice and we were happy, 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 ah, patient, actually, really. Rutherford. Five Not brother for six with, uh, heal wounds. Gangrene, by definition, if it's a rough for six, is really not salvage, So it's really a high level rutherford. Five patients. So you can see here that we've got a single vessel via the Para Neil, but included a t, m P. T. And I wanted to get in line flow from the foot So you can see here that this is what an angiogram looked like. Two we have ah, parallel collateral. But I wanted to get more flow thio this Cal Keano branch and also to the plant of BT, which feeds the 4 ft as well. So what I did in this situation was go ahead and I stuck to the bottom of the foot. Under ultrasound, there was a large plant, a p d target, and we put in place the four or five star slender. You could potentially do the she flys 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 Thio uh, 17 laser. Quite nicely. So in this particular situation, we went with one for term elite. So is easy crossing from below a zoo. 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 favorable approach. Again using the 1 44 elite at 60 40 60 16 60 80 fluids and frequency. We treated the entire segment and then perform the angioplasty of the entire poster Davari. There was a focal dissection due to where I tried coming from above that did not respond. Thio Initial stenting. This predated my attack b t k use. And in this particular situation, I used a focal coronary drug would extend to address this dissection. And this patient did very well. The Hill gang was able to be addressed with agreement, and the patient did well and finally, he'll So with that, I'm gonna have stopped sharing my screen and switch over to Craig here. Well, j, those were great cases, and I think a great point made about using I V s. I use I've us routinely. It just shows us so much mawr. Then we see, um, when when we just simply perform angiography? I just have a couple cases that I'd sent in before. I don't have quite a beautiful iris images to go with them, but these were just cases of what indeed we can achieve when we use laser. Devon, would you advance these please? So this was a patient with fairly extensive gangrenous changes of the foot, Uh, multiple field distal bypass surgical procedures. And we can see here that really all the infra pop little vessels were totally included. This is just a case that two of these vessels the post your tibial and the entire tibia we actually used initially just to get started step by step technique to get approximately, uh, 2 to 3 millimeters beyond the area of total inclusion and then step able to lead through the rest of this and perform D bulking and balloon angioplasty. And this just shows you that often we can completely reconstruct these infra popular teal 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 eighties. This was shown tohave 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. Foot. We consume that there's a patent para Neil. 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. So here you can see again, Coming from above, we were able to wreak, analyze the posterior tibial and achieve very nice feeling of the foot. And this patient again had complete healing. Next slide, please. Uh, this was a patient who was just believe it or not, a severe Claude if it did not have also and didn't have a little bit superficial federal 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 patient wanted something done. And so we actually went in just simply cleaned up these vessels. We achieved all three opening. The patient had amazing symptomatic improvement with this. This is a bit controversial, um, 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 it did make the night 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 plea deal artery aneurysm and had multiple surgeries for pocket artery aneurysm. And 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. 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 joy. And then we lead with a wire and you can see we were able to establish in line slow to the Para Neil. And again, this patient had them salvage Next slide. This was balloon alone. And here we can see the patient again. Another infra popular till, uh, image. I apologize. I can't see my image to the right right now, but you can see post treatment. We have established that, 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 fluid stopped right below the stent that we see in the distal superficial temporal artery. We came down here and hit this with a laser and ballooned, and we were able to establish nice to vessel flow into the foot next line. 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 houses 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 him more effective channel by crossing. It is, 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're just trying to going through some of these questions. So one of the first questions is how effective is laser and tibial CTO s? Um I think, uh, from my perspective, I love using laser for tibial CTO s. I find it to be highly effective. Um, certainly there are multiple devices that people can use. Phillips also has the Phoenix devices. Well, too, but laser has been my mainstay for tibial cto s for a long time. I don't know what you think. Our uh Yeah, well, I think I showed you a bunch of tipple muscles, and I It's my go to in that area. I think it's a very effective to their, Particularly in these patients who any symbolic phenomenon might result in losing their legs. Their most of these people are legs and really big trouble when we start. Right. Um then I think there was one raised hand there, too, as well. Um uh, and if you could take that, take him off me. You can ask a question from the audience. Did you guys hear me? Yeah. Hi. This is, uh, Suhail Khan from Salt Lake City. Dr. Walker, I'm here to listen to two of my favorite people, Walker being our mentor. And it's one off those who like this field 20 years ago where I'm sure people would like question him what the heck he's doing. But he changed the field as we know it. And me and J people like us. We're thankful to him or doing that. Dr. Walker, I have a question. As you know, the Venus ulcers, um, are five times more common than Rto ulcers. And lately, the last 4 to 5 years we're getting to know a little more about Venus disease. And now we have to FDA approved, like the ostensible for that. But I'm going to share one case with you and get your part on. And it was like a year ago. And there's a patient came in with Venus ulcers and, of course, had multiple bane of relations. Um, and and then I checked his Elliot Man. He had previous 10 many years ago. Now that was completely occluded, something I've advocated pretty strongly for, for a area of research Central Maine inclusions and things like that too. I guess there's a question. Is the market gonna be? There also is are the device is big enough is well too. And this also applies to the question that's out there regard to use your laser for filter retrieval. I've done it, but I really can't talk about it because it's not approved Onda. But certainly there's an interest offline. We could certainly discuss these types of things, but this is an area of research and study and hopefully something that they're gonna try to pursue indication for us. Well, thank you, guys. Thank you. Eso There's another question regarding, uh, preferred settings for turbo power in calcium. Craig, I'll let you kind of mentioned what you could do for that. Yeah, I actually go to high frequency. I think frequency is our friend. When we're dealing with dense calcium and and I think rotation is our friend when we're dealing with debts calcium, it does allow you to feel your way through the boulders. But keep in mind that lasers doing something we historically didn't really acknowledge this acoustic shockwave 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 triple 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 J owed you a 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 the laser before doing anything else. And I think some of that is, uh, the laser impact. I think some of that it's a softening of the calcium and and the use of this capitation bubble, you know, 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 Mawr, commonly medial, and that's more difficult to reach that we're not really reaching that. We're hoping to impact with this acoustic shockwave. That's the more common form of calcium before. So there's another question on, but 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 tardy racial for P. T. K. And I'll say I typically, uh, half size it, So I tend to use a lot of one for, uh, laser for tibial vessels. Assuming the center tibial is around a three millimeter vessel of greater, 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 fetal second as well. Craig. Any thoughts about that? 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 is it originates and then is 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, were shaving the papacies of those areas. So in those cases I would downsize. The other time I would downsize is if I thought I'd I'd cross mostly in a true Lumet. But perhaps in a small areas of intimately I would treat that vessel. And the reason I would is the area I would be thinking I would. Making be making the big impact is the area I've treated True Lumina 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 true Luminal crossing throughout in a straight segment, I would try to size two thirds of investment. 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 eso I have no problems using to a triple power even with rotation of the sub internal segment, I've had a 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 that was pushed very hard. Jean Carlo, be amino described it. I think now we have even mawr 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 instant restenosis, particularly if I can get a wire barely into a stent. I'm then certain that I'm inside this 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 catheter to that point, turn energy settings to as low as you can get, turn the energy on and advance a catheter. Very minimum. You're just trying to soften that plaque to really allow your wire to get in and hopefully cross the lesion. You're not trying to cross everything with just the laser. Typically, you're trying to oblate that proximal cap and allow your wired 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 wires and great penetrates. But the step by step, particularly in instead of 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 energies to low and carefully monitor pain. If the patient feels pain back off you publicly in somewhere you should not. So I guess there's, Ah, somebody asking about when you would use orbital atthe erected me over laser. Any thoughts on that? Correct. Yeah, I think orbital after rectum. He plays a real role in In Luminal and Luminal Calcium. Certainly that's a nary an orbital after ectomy comes in much longer catheter lengths. And I'm doing a friend. Number of cases, trans radio. Elliott, this point, And it's really in those cases the only option if I want to reach. But I think that it has a real role in, uh in intra Luminal calcium for sure. And I think is a is a good tool there where I would not use it is instant restenosis. Okay? I don't think it's a 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 echo all of those sentiments as well, too. I mean, it's a good tool on, 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 from ectomy versus using something like realistic or mechanical suction for clot. Um, I could tell you that in in in my world, if I know that I'm in French, thank from this. I typically tend to use more aspiration devices first prior to lettering, because I don't like to make my life hard. I think the technique necessary to address a large dramatic segment requires really meticulous slow advancement less than one millimeter per second to really a blade promise. 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 cloth matters is in very old conclusions. There's almost always some traumas. So when we talk about one month to month cloth, that's one thing. When we speak about cloth 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 out o'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, of, of, of lazing and especially high settings and what Thio 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 effect that could happen not so much thermal damage or things like that, too, but really just e think there's a lot of acoustic effects that happened from the turbo power device. I've typically managed that with with with just minimal pain control afterwards, it typically resolves itself. Craig. Any thoughts on that? Yeah. The one time I've seen people experience pain is then really small stents where you know often. Ah, poorly expanded previous stints. Small vessel. And sometimes if we go in those very high energy Yeah, uh, those cases didn't do well after before experience. It was different for men. Moment. Obviously you want avoid this place Very important. Really working. Really want to get make. I've seen people get big destruction. Could have problems with laser that students were not laser. That's typically because someone doing 70 laser racing back. Uh, most people are not following the rules. Understand? And do you follow that? Feels nothing, Have a lot of problems. Well, that's right, boy. Just mhm. Well, you know, I think that that's great. Um, I think there's also a question regarding Flushing. And then I think there's two ways to flush. I think with with laser one you could do from from your manifold via the sheath and also flushing through the catheter itself. I kind of mentioned an example where, um, if you didn't have a sheet above to flush through or from below, and you're not gonna get adequate sailing flesh, sometimes you could flush with the tip of the catheter. Eso 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 doom or, uh, flushing from thes sheet itself Onda. And I find that to be fairly effective, Craig, any any thoughts of that? I agree with both of those things you just said. That's how I do it as well. Okay, um, there's a comment regarding laser and Papa Teal vessels. This has been a hotbed topic, just like common from our 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 on? How would you treat it? And, uh and, you know, some people are saying doing endarterectomy what not to. But, you know, we've shown some cases of, uh, effective public teal C T o s and high grade lesions being treated laser. I think it works. I like terrible power. for it and using sculpting DCB Uh, any thoughts of that? Yeah, actually, popular delusions all the time. Okay. And, you know, I think it's controversial to treat popular deals. If there's they're not included, and there's a nice otherwise segment, you destroy that segment. Most of the popular tills I'm treating are totally included. And I don't know any surgeon that bypasses, too, and included Pop Little segment. And so I don't have a lot of fear treating a popular Tino 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 titles, and often those were 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 the drug coated balloon so that I don't leave any metal implant in play. And perhaps in the future, if if something is required surgically, there is still uh, that capability of applying a graph. I would I would add, IBIs. That way you can size your balloon quite effectively and avoid the sections, especially in that segment. I agree with that. In fact, I use ivascyn almost all my cases now, Yeah, that you can't get any better than that. Really? Eso There was a question regarding specific lesions for using the trouble family more effectively, and I guess also tossing the question regarding what do you use? Phoenix? Mhm. Eso Craig. Any thoughts on that? Yeah, eso to be I was one of investigators for Phoenix is well in the past. It takes me a little more time to set up the Phoenix than 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 device. It's just I have ah, lot in favor of the 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, uh, the only time I'm using Phoenix, 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. Uh, there are some office space labs and a SCS as well. To if you don't have laser available would be nice toe. You know, you could bring Phoenix in those scenarios. I've had some good results with the two to Phoenix below the knee in the S f A. I still really like laser Ah, lot on DSO. You know, it's still remains my mainstay as well. And largely, you know, in the S f A. I'm using terrible power not using as much trouble eat 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 a 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. Uh, 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 really 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 I mean, you're the effects that are the halo effect there from the capitation. So it's not really a thermal injury. Um, it's more of, ah, photo acoustic effect. So, uh, there's another question regarding the level of evidence and outcome for using laser and C T o s. And, uh, and to use d p. I don't know if that means a drug eluting balloon or what that is specifically. There was ah, common regarding essentially using laser prize are I mean, the CTO s uh, multiple studies have shown laser being used in long length lesions, some of which are cto, uh, to soccer three type lesions. So there's plenty of evidence there that suggests a laser affect me works within those types of lesions. I don't know, Craig, if you have any thoughts on that No, I I agree with what you just said for sure. Yeah, eso Someone's asking about a coronary ct Oh, trial for step by step. I don't know when that's gonna happen, Happen If anyone's gonna fund that study, I've certainly done it. But that's You have to be really sure exactly where you're going. If you could do something like that, it's obviously considerably more challenging. I've seen uh, Dr Lombardi, do it with two laser in the corner before, to which I would strongly not recommend. Let's see here, Uh, what's the largest vessel dime er 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 could easily treat a seven millimeter vessel and even a potentially above maybe even an eight with halo effect. Ah, 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. Pregnant? Uh, yeah. 23 turbo power. When we looked at, I've us in the past fairly routinely made a five millimeter channel by Isis and so a mhm and you follow that to bloom. So I think pretty effective. Pretty effective treatment. Yeah, so you know the acute Luminal game that you get with laser is not, I think, really. As importantly, there's a halo effect you get. I mean, it turns that tissue 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 it without lazing, first you'll find you have, ah, a lot more recoil s o I guess D. P was regarding, ah, symbolic protection. So, yeah, I mean again, we kind of think we address that a little bit, too. I mean, I think that, uh, I were both fairly selective. I think carbolic 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 could certainly make it a bad day. If you have to go chase after clock. Oh, are 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 a long area because of that migration. So, you know, I'm not against district protection. I'm an advocate of distant protection. But most cases that I treat with laser I don't use this for 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 significance in the debris. And so I don't use it very often here. I use this in high. I use this protection when I'm using laser Onley when there's very, very poor run off, and I think there's very new problems. 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 ah, lot of aspiration in the capital 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 questioning. Go no atthe rectum. E 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 and that's because stents in the iliac have historically done fairly well. And, yeah, a question about how do you get back to using laser after not having used it for more than two years? Certainly, if you wanna visit either Jay or us, that's certainly possible. Even in the Cove it era, you know, we haven't o. B. L in Lafayette. That way can certainly work with someone and let them see there's your cases and get a feel for this hospitals air still, right now, little difficulty 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 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 the current group I'm in right now. I started as in the O b L. I asked the question. Well, what after ectomy devices, you have way have laser and I said, Well, I've never used laser before and they're like, Well, you're gonna learn right now, So pretty much I learned after the first case. So it's e 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. Thio with Philips, 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 body silicon. And he says, when we will see us again it in C B H. And so he'll I'll just tell you not soon enough way would we really miss sing everybody and and having the educational forum that we all enjoy being able to all interact with each other. And obviously Covitz made that difficult. Between the physical separation that's required and travel restrictions and groups not being able to travel, it's it's pretty difficulty this year. We're We're trying to do this in a digital Siri's, but we're going to try to get back to this because we do think it's important toe. 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 Beach Florida meeting in March, so we'll see how it goes. Well, you know, we've actually run through all of our Q and A that people submitted, and I know we're 15 minutes past where we were. We thought we might end. Um, so I wanted to say thank you both. So much for going past time and 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 May. I certainly enjoyed it. Got Thio speak to friends. And certainly this is this is a very nice break from the other covert stuff that we've been getting to Dio Wonderful. Great. Well, thank you so much again. This is fantastic Blue. We'll see you on a screen again soon And maybe in person. Really? After that Mhm.