Dr. Kush Desai and Dr. William Kou present on their real-world experiences with laser-assisted IVC filter retrieval using the new Philips IVC Filter Removal Sheath – CavaClear, which is the first and only FDA-cleared solution for advanced IVC filter removal. CavaClear is a clinically proven solution for chronically embedded IVC filters and significantly reduces the force required for removal.
Learn more about CavaClear at
www.philips.com/CavaClear. It's really an honor to be here today on this momentous occasion and to share what we've learned and to review the results from our first in human clinical trial on laser assisted filter removal. Just a few brief disclosures and as well, just a reminder with regards to off label use the permanent type filters that we attempted to retrieve were not designed intended or FDA cleared for removal. Well as has been mentioned many times by now, we're all well aware of the potential risk from an indwelling filter. These include robotic complications, the potential for preparation with injury fractures, civilizations as well as the potential need for ongoing anti coagulation. And collectively this can generate a great deal of anxiety, not just among patients but also with providers. And so the original purpose of our study was to look at the safety and the efficacy of eczema laser sheet. Specifically for removing embedded filters that were refractory to standard methods and high force. This was a prospective single center study running over 8.5 years. During that time, more than 2500 advanced filter retrieval attempts were made at stanford and from that group 500 consecutive patients who met criteria were enrolled to undergo attempted laser assisted filter removal. A small handful of patients were excluded from the trial for the reasons that are listed here. And these were the demographics of our study population. All the data were captured in a hipAA compliant database. As mentioned. All these filters were refractory to standard retrieval methods with high force. Now, what does that mean? It means several pounds of tension had already been applied and failed in the retrieval that's three X. As standard retrieval force. There were actually three groups of retrieval indications that were identified in our trial. As used as criteria number one with the symptomatic patients. It's pretty obvious why we would want to remove the filter and these patients who are already suffering from filter related morbidity. But we also identified a great number of patients who are asymptomatic. And so the indication was actually prophylactic to remove the long term risks that we know are associated with the exposure to a prolonged filter implant. And just as interesting was a third group of indications those who actually came to us already on filter related anti coagulation. And so we wanted to remove this device to filter and potentially eliminate their need for ongoing anti coagulation. The apparatus that we use was the original C. B. X. 300 CNN chloride laser generator that was powering laser tip sheet, calibrated to 16 million joules per square millimeter. And very early in our trial we introduced this concept of digital force assessments in order to try to improve safety. We actually hypothesized that the laser assisted technique with the force gauge use would allow removal of over 95% of embedded filters and using a lower amount of force and with the safety margin that was less than 5% risk of major complications. So our primary outcomes were successful retrieval and our primary safety outcome was any major complication is defined by the S. I. R. S. Guidelines and now results. Laser assisted removal was successful in over 99% and that was significantly greater than our 95% threshold. The main filter dwell time was over four years and the longest succeeded 27 years. The mean post laser force was significantly lower than the pre laser force. And this means that not only were we able to remove these devices but we could do it using lower force, a less much less traumatic removal experience. These are the variety of filters that were encountered in our trial. 11 different filter types. You can see the retrievals along the top as well as removable along the bottom tier and the mean dwell times. You can see the wide range and these are dwell times extending into the decades. Major complications were encountered in 2% which was significantly lower than 5% threshold. And this table breaks it down. 10 different complications were encountered throughout the trial and for us it's more a reflection of the type of patients that we agreed to accept. Very complicated complex cases that we agreed to accept. And if you break down the ideology, only three of these were actually attributed to laser activation either along and embedded apex or a long conical or cylindrical filter fractured components. Fortunately alternatives were successfully managed cutaneous lee and or with medical therapy and so there were no patients who required any open surgery for the management of the complication. We talked about the risk benefit ratio when we're trying to treat patients, all 10 of these patients had been suffering from filter related morbidity and it was all alleviated. After removing the filter, we have three retrieval failures all associated with this filter type, along with chronic cable thrombosis and the presence of that. When you have calcified problems within the filter, um we notice that that is the limitation and the main achilles, if you will, of the laser sheath as in its current status, even the largest sizes may be too small for some of these. Now, fortunately in that case, we were able still to see revascularization by stenting through the filter is our second choice. In order to alleviate the symptoms. But more commonly you would see a conical device that could also result in chronic cable inclusion and this time you have aortic penetration. Now you would never want to step this filter permanently in place. And so after confirming that it was refractory to several pounds of tension, we activated our laser and were able to explain this device using lower force, a more gentle removal experience. And that patient also went on to have full revascularization to alleviate intravenous obstructive symptoms among 133 symptomatic patients who are suffering from filter related morbidity, successful retrieval resulted in immediate symptom improvement and over 99%. Speaking of anti coagulation. The retrieval allowed discontinuation eventually of anti coagulation and over 98%. And that's a big deal for these patients for three reasons. Number one it spares in the cost of taking anti coagulation. Number two, the inconvenience of remembering to take it And perhaps the most important. # three, the bleeding risk associated with lifelong anti coagulation. Now that we have these tools available to offer advanced filter removal, we actually find ourselves asking some important questions. What is an acceptable risk benefit ratio for attempting filter removal in particular advanced filter retrieval Despite encountering more and more challenging cases, can we make the advanced retrieval techniques and protocols safer and if so, who are the best candidates to undergo filter removal? It's such a timely discussion, not just in the subspecialty of IR. And image guided therapy, but if you think about the general medical community, this was the featured clinical decisions making peace earlier this month in the new England journal. The focus was on a case of a patient who presented with a 10 year old filter and the big debate was what to do with that patient how to manage that patient? What was the optimal risk benefit ratio? In that decision making And not long ago we ourselves published R. S. I. R. C. P. G. Guidelines as has already been referenced before but it bears mentioning again the S. IR suggests consideration of filter removal in patients who are suffering from filter related complications. Specifically after weighing the filter versus procedure related risk. Again it gets back to that concept of the risk benefit ratio. In an earlier landmark study by Al Hakim and colleagues they actually compared advanced versus routine retrieval attempts and indeed they found advanced techniques were met with higher success. But there was a big trade off and that there was also a significantly higher major complication rate of over 5%. And if you go back and look at the data and you look at the injuries that were caused by and large most likely from excess force that was placed on the device as well as the vessel walls. And that was before there was any protocol to allow force gauge assessments and before or any is more laser technique was widely available and that's why we hypothesized that using an advanced laser assisted retrieval protocol with force gauge use that we could remove a greater number of percentage of filters with lower force and with less risk of major complications to that effect. We were able to achieve all three of our study endpoints in this trial laser technique, safety in our minds again hinges upon making sure we don't over exert that we only oblate when and where it's needed in order to reduce the risk of cable injury and the excimer laser mechanism itself allows us to achieve very fine micron tissue ablation by harnessing the energy at 308 nanometer wavelength. The C. V. X 300 actually adds just enough energy to disrupt organic molecular bonds and disintegrate 50 micron tissue layers through this process known as photo thermal ablation. Now earlier on in the trial, you know, we weren't sure what this was going to be happening on the southern level. And so we decided to study it histological. E among the 1st 200 filter specimens that we expanded and placed under the microscope and what we saw was actually fascinating. We actually showed safe photo thermal ablation margins to filter here in scar tissue in 98%. And this actually gave us the confidence to continue the trial going forward following that same protocol that I've described. Our study was mainly limited by the fact that the results were acquired over many years at a single center where we garnered a lot of experience using laser and using advanced techniques. And so the overall results may not always be representative. Um, we did identify some important congregations And these contraindications include just being unfamiliar with the laser technique or advanced removal in general. If you're able to capture the device using several pounds 6-7, specifically, then you do not want to be activating laser in that scenario against any chronic calcified dramas. We've seen limitations with advancing the laser in its current form in its current size. And then finally lacing along an embedded or impaled filter apex or along fractured components actually could lead to asymmetric lacing, which we've identified as a major risk factor for vessel injury. So in conclusion, laser tissue ablation has emerged as a viable option for removing embedded filters that are refractory to high force. But please be aware of the contraindications, successful filter removal. In our trial we've seen often results in symptom improvement and those who are suffering from filter related morbidity. And it can also help patients achieve cessation of filter related anti coagulation. For many more details of this study. Here's the full reference. Thank you. Um Good morning. My name's kush, decide it's a tough act to follow um a colleague, a mentor and really the pioneer in this technique. I'm gonna be presenting our data but also I'm gonna be presenting some complimentary approaches and really one of those things is addressing the 2010 and 2014 safety communications from the FDA that really mandated that not mandated but pretty close to mandated from what the FDA can do that. We should be following our devices and particularly given the fact that so many long dwelling devices are out there, we finally have something available. Um That's been studied generally to to approach these patients. These are my disclosures. So we'll talk before how we're gonna talk about why we know about 2010 and 2014 and 2008. Um right around the time that there was a paper from the Northeast where we saw filter related complications coming around and that's probably what moved everything forward in terms of the 2010 safety communication. We at the same time in Northwestern and my mentor Barbara, you realized that we had no organized african track filter patients in 2009 january 1st, probably january 2nd. Actually, he established an NBC filter clinic, much like what well described to. And the idea was is there a systematic way that we can actually follow these patients and improve retrieval rates? This is not about getting better at retrieval at that time, is just about actually following patients. And we saw a significant increase in retrieval rates in 2010, we noticed that our failed retrievals were 10% and we were seeing more and more devices like complications like well we were getting outside referrals and so then it was a matter of upping our game, not just actually getting patients back, but can we be more successful in retrieving some of these more complex devices. This is the filter clinic paper, it's uh very heavily cited and just very basic concept, right, If you follow the patients, you can bring it back for 469 patients or retrieval filters placed between 4010 79% of those are pre clinic and 21% of those for post clinic and I'll just point out here that we weren't actually at that point better at taking them out because we were getting patients back. Our retrieval rates are higher. The critical first step was dedicated personnel people devoted to monitoring these patients and dedicating themselves to the art, the craft and the practice. And we have an R. N. Coordinator. She's my right hand. I mean she is the central cog and all of this without her or an equivalent. It's just too difficult to do this. We're all very busy. Um You need extenders, you need help in doing this dedicated physicians and one in the science of of of how to approach filters uh and the clinical practice of advanced retrieval techniques but also keeping up eventually public publishing results as well has and as we'll show you our data as well. Um we did a lot of prospective enrollment and then we went and looked back which of our filters did we miss some of those more prone to complications which can we get back. So there was a catch up um a lot of internal messaging easier now that we have electronic medical record a lot more email back then and just saying listen we are available to address these patients so please refer them to us if you have a filter problem we'll figure it out for you. You don't need to figure it out. And then organic growth and external messaging where we went from regional like will to a national and international center of referral. I want to approach the idea of dwell time and dwell time is problematic from multiple perspectives. I'm sure will have heard this many of you have heard this as well that filters been in too long, it's gonna be dangerous to remove. And that has been promulgated throughout the literature. We're gonna see some of the papers that pointed this out. These are two. These are two examples of papers that have shown that a greater than 90 day 12 time was associated with filter filter. Now this is before advanced retrieval techniques. This is just what standard chief and sterile technique but clearly the idea that a filter was in that filter can be in too long to be not only unsafe to retrieve but it's not gonna be successful to retrieve. It is an age old paradigm. Then you have the idea of not only is a filter that's been in a very long time, not gonna be successfully removed, but it's also as well pointed out Subject to more device-related complications. And this was a systematic review by Dr. Kaufman and colleagues where they found that most reported events associated with filter-related complications for over 30 days and for all time in many years. And unfortunately this is became a more and more common sight where you had fractured devices um but components embedded in the heart and lungs that are that characteristic death. So what changed the game. And really that's where advanced techniques came in and the laser as as we've been talking about is absolutely central. But there are other things and you need to use frequently in these cases multiple techniques to get yourself in a position to retrieve it successfully. Once you have control of the filter apex, that's when the laser is as well. Just mentioned. That's when the laser comes into play. But if you don't have control of the filter apex, you cannot use the laser. So we'll talk about some of the techniques that you need to um To successfully retrieve these devices. This publication that we published in 2015 was simply aimed at refuting the whole 12 time thing that dwell time is not correlated with our ability to successfully retrieve filters. And this was 648 of art retrieval procedures. We had a 97% retrieval rate and we did a multi variable regression analysis and what we found was technical retrieval success is absolutely independent of filtered. Well time and adverse events were independent as well. And as you would expect and has been shown to other other centers data the longer than it's been in, the more likely that you're gonna need to go to your bag of tricks that you're gonna need advanced retrieval techniques and it's gonna be beyond simple sharing snaring sheath technique. We then went on to identify at least from our center. What was that? Inflection point in time. When should the refers. Think about. okay, my local expertise may not be great enough and we need to refer to somebody that does a lot of complex filter retrieval. And so the idea behind it finding an inflection point was sort of born of that and this is from 2009 table of 2000 15. We used all of our prospective, we acquired data and 762 retrieval procedures. We went back through the literature and this actually came out of a nephrology journal, nephrology journal where we did a spline regression function analysis and through some statistical trickery, which I'm not gonna pretend to completely understand. We found that at approximately seven months if you only had standard And they're available to you, you were gonna fail 41% of the time, obviously unacceptably high. So this is the this is what we can go out to the community with at least a general number, maybe it's not generalize able to all centers, but with the general number that around 78 months start thinking about maybe referring out your your filters if you don't have local expertise to do complex filter retrieval. We then decided to publish a little bit about the actual techniques itself in a pictorial asset because everybody likes pictures, it's dry to read about this stuff. So we, in radio graphics, we published, we published our diagrams and schematics on how all these advanced retrieval techniques are aimed at sort of addressing different problems with with these devices inside to the first is the Lubar technique. It's been well described. I think we described it. The C. L. A group decided you might describe it as well. I've I've lost track at this point, but different variations on this and we've taken on the variation not in general looping a wire and exchange length hydrophobic wire through the filter, but instead targeting the cap. The reason why we don't go through the filter is that you can apply a symmetric force unless you are exactly orthogonal to the long, acting as the filter and that the sheet is going to come over exactly center parallel. You are or not. We're talking about like parallel. Then it's then you're exerting asymmetric force and you're not going to sheet the filter. So, the idea behind this is targeting the fiber and cap that so frequently embeds embeds the apex of the filter against the cable wall, utilizing a reverse curve catheter, a hydrophobic wire and a snare. You need at least a 12 french sheath. And frequently, as we've gone on. In our experience, we're going to larger sheets such as the 16 front sheet. This is a schematic to just kind of pictorially represent what I'm talking about, reverse curve catheter getting underneath that um that fiber membrane sending a loop wire through and then sneering that side of it and then pulling on it and many times the whole filter comes out with it. Um if it hasn't been that long, uh but frequently what also occurs is that you just release the cap and then now the filter can be snared and you can apply other techniques as necessary. A couple of videos here just to kind of show how this works. So you can see diver this reverse curve catheter here and I'm not through the filter again, I'm just on that radio lucent apex and then we snare a exchange like hydra filic wire and so we have both ends coming out of the sheet and then we just put um he must stand on the back end to provide attraction platform. And finally we send the whole, we send the whole sheets down and in this case we were able to get down to probably the mid portion of the filter and then over that we advance the laser sheets to perform photo thermal ablation. Forceps has become absolutely central to my, to our practice. The original brachial forceps are provided by this company line, all 41 62 although my understanding is that they may not be as widely available now. So we're looking at some alternatives for potential forceps because these do have a shelf life, the teeth actually wear out on them and you you need to get new ones. So we're trying to figure that out maybe we'll talk about that offline. But um this is similar to the loop our tech, you target the embedded filter apex. And actually the loop wire technique outside of maybe by conical filters is largely gone by the wayside. At least in my practice I go to, I'm very comfortable with forceps. I go to that first. In in terms of capturing the filter apex, you need at least a 12 front sheet because the forceps will go through it. But frequently you're gonna need a 16 front sheet because the problem is, is that what the forceps are on top of something and you have the jaws actually open and grabbing the apex or tissue. It's gonna be too small to fit the 12 French. It's gonna be too small to actually fit the device. Um you want to you want to be very careful when using forceps, patients can get very, very uncomfortable if I anticipate extensive forceps use based on if I know I'm doing a complex procedure. Um these patients are under anesthesia at least some sort. monitored anesthesia care while we're doing this, you don't want to just indiscriminately bite down when you're doing it. What I typically do is we the forceps are available as you see here and then we just take a clock face approach until you feel metal on metal and then mentally, nowhere on the clock face you are. And at that point, start gently trying to come down on the filter as you see here. Another schematic, same idea. You're pulling that fiber and membrane off. and then working to capture the filter. So sometimes you're gonna be. And this is a technique that was initially described by the pen group and they published a lot of their results on this. Um What you initially may do is just capture the apex, but in some cases you can't feel the metal and so you're going to be just actually peeling a little bit of fiber and off, and you'll pull it, pull it out of the sheet, and you'll see little bits of white material come off until you can feel that metal. And then once you do this, and you can see that this device was fractured. We'll talk about that in just a second. Um We then use the, with the forceps having a firm grasp of this, we then take our sheet over it to to successfully retrieve this device, very helpful for fractured fragments. Um My personal approach is if I see a fractured fragment, um and this is based on a couple of things that occurred early on in our experience, actually go after that first. I don't go after the filter first, because manipulation of the filter, sometimes it requires you to torque the cable a little bit. Um you can actually dislodge that fragment and I've had to go and chase them out of the lung and that's not something I'd like to try and avoid that. So we take the fragment out first and then the laser. And so you can see somebody's tried to retreat. This. The hook has been slightly straightened out and so they probably as well as well mentioned with the force gauge. They probably pulled extensively and they couldn't release the filter. And these filters at least in our experience with the most likely to need the laser. Which is that close cell design because that close cell design has such an extensive surface area uh contact surface area with the cable wall. And so the rate of industrialization or the the exuberance of industrialization is much greater than open cell devices. Of course, open cell devices do need laser as well many times. But frequently with the close sell devices where we've noticed and I'll show you our data in that regard. Just to give you an idea of how this is tethered. We took this pic early in our experience where we have we have everything down, the laser's ready. We haven't quite activated yet. And you can see exactly where it's attached where the pedals in this case are meeting with the primary struts and that's where you have all that zone of contact. And so this is where you just activate the laser while maintaining traction and it releases very quickly and then you successfully treat the device in the interest of time. I won't go through this because well describe the technology beautifully. Um It's a cold. The action of laser is a cold laser photo thermal ablation that disrupts molecular bonds at the at the site of the implant. I believe we have a new box coming. That's gonna be a 1 10 to 20 which I should actually broaden the availability of this. Our rooms have 2 20 bold outlets built into them because we anticipated meeting them as our practice group. But uh with the move to 1 10 device, it will be much, much more broadly available. Another schematic from the radiographic paper showing how this works application laser. Once you get to that point of of resistance and then while maintaining traction, it's important. This is actually something worth worth specifically mentioning. Any time you try to filter. It doesn't matter what technique you're using, whether it's a sheath and snare whether it's forceps or whether it's laser, you have to think about it mentally as two vectors. One vector is your sheath coming down, the other vector is your traction platform. And you want those arrows to cancel if one arrow is too big this way or this way that's when you get cable and deception cable ruptures those kind of things. So you have to mentally think about pulling as hard as you're pushing basically. And the laser allows you to pull and push less hard when you have when you have an embedded device. And then just a quick video of how this is working. This is another closed cell device here And we got down to that point where you have a lot of surface area contact with the ibc and activate the laser to retrieve it. I like this picture because it shows you exactly where it's attached. Those little vibrant threads right where the pedals in this case meet the primary struck and that's where these filters get stuck and you can see that somebody did try to pull on this on to the Northwestern data. We published this in the General american heart Association 2020. This is 441 of our patients with filter implantation times over six months or prior failed retrieval attempts at outside institutions. And standard retrieval attempts, attempts were uh standard standard retrieval technique was attempted prior to escalation to advance retrieval technique or if somebody else had documented failure of it. So, for example, if somebody tried with the snare and I have a ct scan that shows that it's tilted and embedded in the wall, I'm not going to open a snare, I'm gonna go to something else. I'm not gonna try a standard technique there. And our hypothesis was that close cell design filters were more frequently going to require laser sheet application for a safe and successful treatment. Our overall technical success is 98%, In laser cases, the laser sheep is required in 40% total and much more frequently in close cell designs with a 20.1 odds ratio that that's just our observation. Um there was no significant difference in time between the open and closed cell 54.4 months. Um I mean in 58.5 months and the open cell devices there were three total adverse events, one in the laser cohort. And that this is just going based off of s ir adverse event criteria. This is the gentleman that had like conical filter. We had to access the growing. These are large sheets and he had a growing hematoma and spent a couple nights in the hospital as we sorted that out. So we concluded that if you think that you're gonna need this device and I don't know what it's like at stanford or what it's like in any one of your institutions. But we share this box with vascular surgery, ep cardiothoracic surgery. And so you want to plan ahead these are elective cases largely. And so you want to make sure that it's scheduled the boxes available that you're not taking on a case that you have to bring the patient back, expose them to the additional risk of anesthesia and an additional procedure and you puncture all of those things. So we have everything planned in advance. The boxes in the room. The disposables are not open until we need them but we have everything available when when when you're taking on these cases so that I think we're gonna move on to a case and I believe you're gonna go first year. Thanks. Kush. That was that was great. And this is an opportunity now to review specific cases to talk more about the details how we identify patients, what the indications are, what the potential risk may be and how we use laser specifically. So this was a 66 year old male who presented with a gunther Tula filter. This had been placed 12 years prior. This is a prime example of a closed cell design as cushy as mentioned. So right away when you hear that history, you think there's a high likelihood that this patient might benefit from laser tissue ablation. So he's now presenting with a four year history of severe bilateral lower extremity pain swelling and he's got non healing wounds, venous ulcers, lofty scores exceeding 30. He's also unable to exercise. Not just because he has pain in his legs and swelling, but he also complains of severe dystonia on exertion. See Tv shows some pretty classic findings, chronic illegal cable inclusion and penetrating filter components. And again, an example of what can happen when a filter that was only supposed to be temporary was left in. So what are the indications for removal in this case? So, ideally we'd like to remove the robotic filter notice along with the penetrating components and that in turn would allow us to achieve full illegible revascularization without jailing in the filter. If we're able to achieve this, then hopefully we can alleviate his severe pts and promote his wounds to heal and maybe we could restore his cardiac preload and his exercise tolerance on top of all that there's a psychological component and we see this time and time again, the patients themselves have taught us how to think about this, what it means for them to have a device that's been sitting there that's now penetrating, that has a whole constellation of findings. It actually generates a tremendous amount of anxiety in these patients. So the good news in this case is that the bilateral common femoral veins were open and so we access those and you can see from this initial venogram there's chronic total occlusion of the infra real ibc as well as both iliac. And there's reconstitution way up here, the super renal ibc right above the filter. Other findings that I've mentioned, there was light penetration. There was also the tip of this filter was scarred, ingrown into the wall. So you have the full constellation of an end stage device that's been left in now for over a decade. And just as a reminder of the clinical six Pts, non healing wounds, cardiopulmonary exercise intolerance essentially has no normal pre load. He's got penetrating filter leg complications. He's got anxiety from having this filter in place. So these can now be done in a single session under anesthesia. And now that we have is more laser, we have the capability to achieve advanced removal along with full revascularization and as a first step, we very carefully re vascular eyes through the filter, making sure we don't pass through the interstices. And I did this floral save for a few reasons. But the main was to show if I can get this to play. If you notice this balloon inflating along a 12 year old filter, you'll see where the web is. I mean it's exactly where the filter is. And so it's no surprise how over time this device became a throne majestic knight is. He would have no other reason to thrombosis I V. C. I mean there's no math, there's no obstructing lesion. But there's a filter in place and again, you can see the legs of this device penetrating out here and the tip of this filter is firmly embedded. So now that we re vascular rise through to a limited extent to allow the insertion of certain devices. As I had mentioned, this is a go to technique the endo bronchial forceps that we use. And again, you must use these very carefully and in the right location. These are very good for the embedded apex embedded. A pcs. However, I've seen other operators use these unembedded struts and they try to rip the filter out and often times you can remove this device by risking the filter out, but you can also cause a lot of complications. You know, it's already been mentioned in the earlier lecture that we've shown laser has the capability to remove filters using lower force and what that means is a lower risk of traumatic vessel injury and filter fracture. If you if you think about four steps, on the other hand, four steps can generate extremely high amounts of force. And it has been associated with higher risk of vessel injury as well as a higher risk of estrogenic filter fracture. And if you take a look at the complications specifically of four steps versus laser, the four steps specific major complication rate is over 7%, which is actually over 12 times higher than the laser specific complication rate of 0.6%. In addition, four steps are also associated with an 18% androgenic fracture rate, including filter fragment globalization into the heart and lungs. And as doctor, as I already mentioned, you know, when you're dealing with filters, oftentimes they come to you and they're already broken or they're very brittle and you can actually have immunizations even without doing anything but just barely touching the fragment or the filter. But you certainly don't want to introduce that risk by placing an excess amount of force on an old device. And just as a reminder, we took a look at the breakdown. In terms of laser, we had no such complications. We had no e estrogenic fractures or embolization that were caused by the technique. And the reason why is we're very, very careful. Once we secure the apex, we actually go back to the ensnare attached it to the digital meter and here you see £6.5 have been applied and were not unable to sheet the lower half of this device. But now that we have laser we can go to lower amounts of tension and let the eczema laser energy do its work. So the laser technique with the digital gauge allows successful removal at lower force in order to avoid major vessel injury. This is what happens in real time when we reach the distal aspect and it's kush alluded to. You don't want to be pushing too hard or pulling too hard. You want to be really gentle here, you don't want to drive the tip of the laser sheet too far against the walls of the ibc, especially where not only the legs are embedded but there's also quite often penetrating filter components. And so we actually instruct our trainees to be really mindful of the radiology and what we see on the CT beforehand and what you cannot see on the floor. Oh on the live floor. Oh um quite often, you know, you have to predict where those penetrating components are and will actually place that reference image from the initial venogram which shows the penetration along with the C. T. Scan just to make sure that once we get to the distal aspect, we're gonna hold the laser tip, the laser sheet stationary and we're gonna go to half the amount of tension that it was refractory to and let the laser do its work. So let me play that one more time. Mhm. If we can get that to play here we go. So here we are, three lbs. We're activating laser. You can take a take a look. The laser sheet itself hardly moves. We let the penetrating components come back into the into Luminal side. And this cartoon illustrates it even better because it actually shows what happens the path offices of the fiber optic tissue that forms along the attachment side, the tissue that you cannot see on the live floral, but that you can actually feel. You have the tactile sensation of something being tethered in place. And as I said earlier, it's very common to have penetrating components. And so you have to be really mindful of where those are. And so once the device has been confirmed to be refracted to several pounds, it actually gives you the confidence that you have enough tissue there to safely oblate. And so here after confirming several pounds of tension, um we're unable to remove this device, we typically go at about half the amount of force. And we let the laser energy do its work again, being very mindful of where the penetrating components are. And since the energy of the laser sheet, the energy is emitted parallel to the vessel walls, the risk of significant vessel injuries also minimized. So once the inherent tissue is a bladed, the distal filter legs, including the penetrating components, can now be retracted safely into the vessel lumen and captured within the laser sheath and again using a lower amount of force, it's much less traumatic. The chronically embedded filter can be removed safely detached from the NBC wall without injuring the underlying Kaveh. Um And as I showed in some beautiful examples of his ex plants, if you look really closely, a lot of these devices you'll see tissue left over and what does that look like under the microscope. Well, here's an H. And E stain in 100 X. And it actually shows focal areas of photo thermal ablation. I remember the first time we submitted this to the pathologist, we didn't tell them what we had done and they immediately called and said, you know what, what, what happened to this tissue? We haven't seen anything like this. And that was actually the first sign that the energy itself was having an effect on that cellular level that we talked about. And then we got even more sophisticated with the staining. And the recommendation of our pathology guys was to conduct TVG standing because this analysis also allowed us to not only detect that we could oblate tissue, a hieratic tissue, but we actually use it as a way to identify if there are any cable elements because occasionally we would see cable wall elements, particularly with penetrating components. Or in cases where before we had dialed in our protocol, maybe we shaved a little bit too much ibc tissue. So once the filter is out, especially a penetrating obstructing device like the one I've shown we can move a lot more confidently with achieving full revascularization and here you see an I. V. C. Extent that's been placed here. We are just going about our full revascularization on both sides and the end result is a restoration of full illegal cable flow in a patient who's been obstructed for many years. And what that means for the patient is we've alleviated his pts. We've enabled him to heal his wounds. We've restored cardiac preload, restored his exercise tolerance, taken out the penetrating components and overall we have alleviated his anxiety. And so that's the power of laser in terms of being in a portfolio and armamentarium of equipment that we can use to help these patients and we can now do all these cases in a single session. A single 3-4 hour session under anesthesia. Thank you. That's a great case well and you know, doing these kinds of cases. I firmly agree that if you can retrieve the filter there's sometimes you can't I think by conical filters particularly and cable inclusions are difficult but they're also more amenable to reconstructing through. There is a conical filter if it's penetrated through. We've seen some we've seen some complications from other centers actually I just mentioned this yesterday that there was a patient that from the U. K. That had a filter that was reconstructed through and the filter component than perforated through into the duodenum there was the continuity of the duodenum with the stent. The patient became septic and died. So if you can remove the offending device in the audio cable inclusions, I certainly strongly advocated. We've written on that as well. So this is my case, a little bit unusual. 65 year old female history. Multiple dvt is primarily in her left leg. She has a symmetric enlargement of lord extremity, extensive venous stasis changes with skin damage, varicose veins and venous qualification. She's on indefinite were from therapy. Retrieval filter was placed in late 2017 for preoperative mechanical prophylaxis before a knee replacement that was placed by a growing approach and retrieval attempt. In early 2018. Rhombus was noted above and below. The filter and a second super renal filter was placed on top of that. Uh The referring operator attempted retrieval in 2021. And pornography at that time demonstrated Peyton ibc so that rhombus that organized trumpets or whatever it was. It's gone now probably an anti coagulation. It was remodeled but was unable to retrieve that cranial filter and referred it to us. So I'll just go through this and you can see there's one in the paddock segment and the second one down in the infra renal segment. And also you can see that there's a post robotic obstruction of the left external and common iliac vein. You have that thin linear calcium calcium that's going through. I'll let this play through again. And there's a couple things to note here. I can pause it. Maybe don't look like I'll be able to. But the first one feels appeared it's certainly penetrated through but it appears relatively well centered. But the second one is more problematic and I wish I could pause this. Not I think we'll see this on my floral images. The second one looks like the apex is actually through the capable. So that's gonna be a different approach. And I'd be curious to see how you'd approach this but you need to get basically reposition that filtered with into back into the cave to and frequently. What ends up happening is that you have to invert these devices at least in our experience as well. So then the laser doesn't come into play. But with the top one is a long dwelling device. We know the laser is going to play a role. So now we're gonna need multiple acts. It's called a filter with that apex projecting through the cable wall is not going to be readily accessible by the jugular approach. You might need adjunctive jugular access to do something with fragments or whatever that may be left behind. But your primary working sheet for that. That filter with the apex through the wall is going to be from the groin. And then you'll need to judge their access for the cranial filter. We prepare with the laser sheet and the laser box being in the room as well as forceps being available to us. And this is gonna be a complex procedure. So we're gonna make sure that this patient center general anesthesia to two so that we remove the element of sedating the patient and managing a sedated patient while we're doing such a procedure. So you can see that it's already fractured in this first image, there's that one strut that's already pointing out and that's from the coddle device that's projecting through the wall. Um Here's an initial A. P. K. Program maybe maybe looks like it's inside. But again, as we know as radiologists that one of you is no view. So you have to try and find the view that's going to show you exactly where the apex lays. And this is an oblique and you can see very clearly that the hook is penetrated through the cable wall. So we're not gonna be able to get this entirely contributor access. So with that filter fracture, into projecting through all my positions, you're gonna need to invert and potentially either reposition the apex back into an intra Luminal position that you can apply techniques or what frequently happens is as you're trying to pull it through the whole thing converts from the groin. And I'm gonna say that this is not something that should be taken upon lightly. I don't particularly enjoy inverting filters from the groin. It's it's one of the scariest things that you have to do. But there really is very few other options for dealing with this apart from a major open surgery. So this is what we're doing. We can see him working in an oblique and very carefully pulling things down trying to reposition it. And this device particularly is single piece laser cut night and all this is an option filter. And so I wouldn't clearly advocate doing a full inversion with devices that are welded or soldered together or whatever you want to call multiple pieces. Single piece laser cut and I know you can do it. There are two devices that are single piece laser cut option in Denali. The rest, I think I would be more inclined to reposition the apex back into the into the cable, into the cable, aluminum that work from the jugular approach. You'll see that we then use the jugular access to pull out the fractured fragments that you see here. And then I needed to use a different type of forceps that duck bill to help me get that final one. So, the main thing here is that you move every fragment because any any remnant intra Luminal fragments represents an embolization risk if you leave it behind. So you if you can't get it, then it's incumbent upon you to prove that it's not within the cable looming anymore. That includes either doing multiple bleak kappa grams or potentially called BMC T. That's terrible to you. So, I wanted to specifically show this case because this is your you can expect this to happen if you do enough of these cases. This is a contained cable rupture. We've seen this. This patient is completely asymptomatic. They may be in pain but they're under generalized seizures so that we don't know that part but completely stable. You have a contained extract. Ization of pseudo aneurysm. So this is when you need an inclusion and available to you in the room. So we put up, we put up this is an excluder or not exclude er I forgot exactly the name of this boston scientific conclusion balloon that we put up. You can use a coda, you can use this uh the bridge balloon which of course it's awful able to use that for this purpose but also with also worked well and we just put it up for a few minutes and then we repeat the run. And frequently in our experience it's still there. Sometimes it gets a little bit smaller but it's usually still there but as long as it's not getting bigger, we feel relatively uh we feel relatively good about moving forward. We then go to the much more frankly monday uh super, super renal filter And this came out within a matter of seconds with the laser as you can see right here. So this is the final and you can see that there's this little bit of irregularity in that cable. We monitored this patient overnight. Nothing happened. No new lower extremity edema. There was no onset of DVT. She is anti coagulated. So we sent her home, she came back two months later, she was from out of town um for recapitalization. We performed the recalibration as you see here and then we check the cave and it's actually this is what we've seen in our experience that it remodels and closes and those we've had much much larger pseudo aneurysms that in the low flow and low pressure state of the vena cava, as long as it's contained, they remodel and close on their own because the laminar flows down the center of the cable lamentation that pseudo aneurysm closes. So I think with that, thank you all for your attendance and obviously available for any questions you have. So when you open the actual laser machine, you grab your filter first and then take the strain gauge and then go back. And so although it's probably good for us to go through briefly with her work for what I typically do is I don't have the disposable. The laser sheet open. We're going with the base sheet will go down to the point that we know from experience is gonna be the point of maximum resistance and we're just trying to pull. Now. We don't use the force gauge but we also just kind of know that it's starting. We're gonna have to pull hard and we just stop, I leave the base sheet over the filter, disengage the snare, send the laser sheet down, recapture it with the snare within the base sheet and then laser it out. Yeah. Just wanted to repeat this gentleman's question for the record. I believe you were asking when do you actually open the laser sheet? Um That's a great question. And probably another question to ask before that is when do you bring the laser generator itself into the room? And this is why we see our patients in clinic and I'm I'm sure kush does the same. Um after having enough experience and gather enough data, you can predict which cases are gonna have a high probability, high likelihood that you're going to actually need the laser generator and then you can even get down to what size, laser sheath and you know, have a clear is fortunately available in the two larger sizes but the original system there are actually three different sizes. 12, 14 and 16 as far as the protocol in the room. Once we confirm that the filters embedded, I think I try to show that in these earlier slides um once we confirm that, hey this is not coming out with several pounds of tension, that's when we'll actually open it up, calibrated. We actually have safety checks as well. Our hospital were required to do laser time out. There's just some basic safety steps that you have to take, including eye protection for example, and the way that the system is calibrated. Did that answer the question? I see. Yeah. So you want to know um in terms of letting go the device um and versus having to recapture. So we've learned over over the years how to maintain access. In other words, the snare itself can be used as a tracking wire and especially for a hook, hook on a filter, you can use that to do the exchange and to advance the co axial laser sheet system. Probably easier to to talk about that in a hands on workshop, which we're actually gonna be on tomorrow morning over in the expo and a human stasis using the actual Yeah. Okay. That's a wonderful question this gentleman is asking all the right questions here. So he wants to know about homeostasis because if you take a look at the apparatus as it exists now, there's no him a static valve on the back end. And that was an observation we made from the very beginning. And we've actually experimented with a variety of sheet combinations that can fit in there snugly to create the human static valve. We can go over the specific specs tomorrow morning in the in the expo session. But yes, you I prefer to actually have a coaxial, smaller sheet in there. I'm not sure what dr side uses, but what I typically do is um the collect, we we do use colossal sheets, but if it's a looped wire often you can't get it through the colossal sheets. In that case you just have the room ready. What happens as you get to the point of maximum cable collapse, the cables collapse so there's no blood return and so then bleeding, we'll see, so then you go through, but if it's just a snare then in that case, yes, we use we use something to operate the whole, you know, a french, whatever it may be. one thing I will point out is we have the box in the room calibrated, ready to go. The disposal is not open, but the box is in the room and turned on so we don't have a five minute warm up at least with our current device that we have. Yeah, that's a good point. If you think you're going to be using the generator occasionally, the tech will forget to turn it on and warm it up and this is what the original CDX- 300. Um we're told that that's going to be phased out very soon and the newer system, I guess warms up a lot faster. You have to calibrate the sheet itself, but you have to calibrate it with the calibration fiber separately, so you have to calibrate the box and you have to calibrate the actual sheet. Have you done a few cases. Yeah. And how long have you been working on using device? Okay, great. So maybe you've come across some of some of our papers along the way that they were helpful. Okay. All right. Any comment specifically? They're more challenging anyways. So to repeat the gentleman's question, you're asking about removing the Simon Knight in all filter? Yeah, sure. So, um actually, I think at at the venus symposium, meet the experts for phillips. I showed that Simon Knight in all that resulted in an illegal cable collusion, much like those case that we retrieved the challenge with Simon. Right, So you're gonna sometimes the snare will hold it. Sometimes it won't, it depends on actually how much tissue on top of it. So there are a couple of different devices. One of the devices, I don't know if you've used this. I've used the Captain's device actually would sign a knight in all specifically because there isn't the bushing at the top, otherwise isn't capture it. And the nice thing about the advantage device that captures devices, you can actually slide the laser over it. So it's this night and all mesh funnel that then you ratchet closed around them and it's got a little teeth on the inside of it and then you can disconnect your, your torque on the back and slide the laser over it and reconnect your torque and that's your traction platform, which is what we did for. That's what I've been doing for saturday night now earlier on before that device was available, it was often sometimes you get lucky and snare works, but otherwise it would be a looped wire that you had. That would be different than what I described in my initial talk. In that case, I actually would go through the filter and you have to be very careful that you're dead center on it. It's a great question and we've had quite a bit of experience actually encountering that scenario and we've learned a great many things. So the wire loop technique that kush mentioned, which has been used and written up in multiple institutions, it comes in handy for that device. If you're able to weave through the umbrella, you can generate traction to try to collapse the umbrella first and then the legs. What we've seen is that as a whole spectrum of presentations with Simon Knight in all um from not much scar tissue where it's easily sheath with just several pounds of tension all the way to meeting laser in particular to a blade. The tissue that accumulates along the umbrella part of that cone. Um, but we've also seen cases where there's dense calcified rhombus within it, which is um where were unable to remove the device. So, and it bears reminding the audience to, as I said in the earlier talk, um that's as as a permanent filter, Right? So it's not actually FDA cleared for removal. So just keep that in mind too. Thanks. Uh oftentimes you're going to attempt these previous attempts by and they're often fragile and fractures distantly when they do move into the pulmonary circuit. How often you're able to successfully retrieve those fragments? Question I want to know exactly what I'm dealing with and that's the purpose of the clinic visit because there's counseling involved with this. You have a device for this patient has a device that the integrity has been compromised. There's a risk that even with the best technique that you'll have migration and urbanization of fragments. So we talk about all that up front that you might need excellency and these are the risks associated with the differences, of course, with the fracture fragment that's inside you. If it occurs on the table, I watched it happen and I can manage it. If you're sitting at home on the couch, watching tv might happen and you don't know until it's too late. So that's one of the distinctions we make specifically with regards to removing fragments, fresh fragments that go into the pulmonary artery relatively straightforward to retrieve that. Typically just a long sheet, this shuttle and then, you know, a snare and you can take it out um intra cardiac fragments. People have had have had some success. I know you publish your results in the pen group has published the results. I think it's roughly around 60% maybe lower. I don't know. It's not, it's not anywhere near the success rates that we get for filters and for for filter retrieval itself. And what I would point out is that in a beating heart three dimensional structure you have to be really careful pathway muscles, Cordy all sorts of things. You can get tangled. Patients frequently become develop arrhythmias on the table and if if in the one case where I've had a fragment migrate to the heart and I couldn't get it out, um that patient and ended up lodging into the track custom valve was within a millimeter to the right coronary artery. Was a young patient that, and this was actually not even a laser case. Um there was, it was a fractured open cell filter. Um We, the cardiac surgeon took it out. Yeah, I mean, that's a great question and it's one of the most feared complications of these devices that they can fracture and parts cannibalizing the cardiopulmonary circulation. When we analyzed about half a decade's worth of data on the outcomes of fractured fragments, we actually came to the conclusion that most of them can be removed as long as their intra Luminal and they're in the proximal portions of the pulmonary vasculature. But when it came to the cardiac subset, um the retrieval success was only about half or 50-60% as kush mentioned. And so that is probably one of the the ultimate frontiers in terms of what's capable to do and what is that risk benefit ratio. Um We've learned over time to that there are certain fragments incidentally discovered in cardiac structures that can actually be left in safely. But the onus is on us to prove that it's been stable over time. And so we turn to cardiac gated cT scans and and monitoring to reassure ourselves and the patient that this fragment isn't going anywhere. Um now conversely we've seen the opposite. We've seen fragments that for whatever reason decided they were going to land orthogonal lee against the RV free wall and perforate through and cause a hemo pericardium and it becomes a surgical emergency. Um There have been a handful of cases like that. We're able to spare the patient from open cardio thoracic surgery by decompressing with a pericardial drain the hemo pericardium and then very carefully very gently removing the fragment from the free wall. So there's a whole spectrum of presentations and as kush is alluded to. Oftentimes there's multidisciplinary involvement and there's consultations, we've had cases where we simply weren't able to get the fragments out and they had him a pericardium with chest pain and they had to have cardiothoracic surgery as the end result. But we've also seen entire filter symbolize uh and some of these more recently were analyzed. Um it was caused by the actual failed retrieval attempt. So we've seen cases where the filter itself, uh they attempted to remove it but they were never able to secure the apex. And the, you know, the whole device ended up m belies ng and the patients had to be airlifted to our center. And we had cardiothoracic surgery on standby. And we made attempts to remove the device per cutaneous lee as a first step. So these things can spiral you know out pretty pretty quickly and you just have to be be ready. I mean as part of your part of your work up for all your patients getting cT scans prior to you actually going to do the retrieval they're getting. They frequently have cT scans. I mean you can't really go to the E. D. Nowadays without getting a cT scan. Um So they frequently have CT scans. And at least our personal approach is if it's a long and well device and there's been a Ct within the last 12 months. I don't personally subject them to another. Um But if they haven't had one then yes we want to know what we're starting with before we move forward. Yeah that's a really important question. Um I think for for our centers you know we actually take referrals from all over. That means that either the patients failed removal sometimes multiple times or the case has been deemed too complex to even attempt the removal. And so it's pretty mandatory that we're gonna have a ct scan that's been done at least within the last several months to a year depending on the filter type and the complexity of the presentation. You can make diagnoses to of other pathology that's related to the filter that may not be so obvious, especially with the prolonged filter implant. Um You can you can detect conclusions and fractured pieces that often times were the first to tell the patient that the filter was broken. They never knew that. Um But it's really important to have radiographic imaging um at least on a fundamental level to identify the actual filter type. Some of these cases are coming to us after longer and longer dwell times. And and sometimes there are filters that are no longer being made and so you have to identify the device and then come up with the plan based off that. Alright. Thanks everyone. Um And yes actually please do come to if you can to the hands on workshop and we'll both be there with models and other devices as well. Thanks