 to the Texas Heart Institute Educational Programs on Innovative Technologies and Techniques. The topic of today's presentation is the latest advances in TAVR, how to significantly reduce conduction disturbances. I'm your host, my name is Juan Rick Rezier, clinical professor of medicine and cardiologist, Baylor College of Medicine and international cardiologist at Texas Heart Institute and Baylor St. Luke's Medical Center. The special pleasure today to have a special guest, Dr. Hemala Gada, he's the president of Heart and Vascular Institute and medical director of structural heart program and staff international cardiologist at UPMC Pinnacle in Harrisburg, Pennsylvania. Welcome, Dr. Gada. Thank you, Dr. Kreiser, it's a pleasure to be here. Welcome. Here are our disclosures. I have no disclosure related to this particular presentation and Dr. Gada also states that he has no conflict of interest pertinent to this presentation. So, as we know, significant progress has been made for the last decade and more in TAVR related to incidents of many complications that can occur during TAVR and this includes vascular complications, incident of stroke, annular rupture and variety of wire perforations such as pericardial or atrial or tamponade and also need for the pacemaker. As we can see here from this information published in circulation in 2017 related to the 30 day permanent pacemaker and implantation rates that they vary significantly between different devices but also from different studies. But needless to say, the incidence and the need for pacemaker implantation could be all the way up to 37% from several studies which is prohibitively high. So, conduction disturbances that occur for TAVR and the need for permanent pacemaker implantation depend on many factors and many variables and some of them are listed here such as type of conduction disturbances that occur during TAVR or conduction disturbances a present prior to TAVR. Also, baseline comorbidities can drive this need for permanent pacemaker implantation and also whether the patient is planned to be discharged early from the hospital also several socioeconomic factors that play a role as well as need for extended cardiac monitoring that might not be available to certain subset of patients. So, all of those factors influence our decision as far as the need for permanent pacemaker implantation. So, Dr. Gada, you presented at TCT in 2019 data from the Evolute Low Risk Trial related to permanent pacemaker implantation and some very meaningful and important information was presented related to this particular problem. Can you discuss this a little bit more in detail what were the findings and what have we learned about the need for pacemaker implantation with this particular study? What we found in the Medtronic Low Risk Trial is that Evolute had a pacemaker rate at 30 days and effective pacemaker rate with transcaptorortic valve replacement of 17.4% in a low risk population and that is just not acceptable. But really the truth is in the weeds a little bit because it's not a very solid 17.4%. So, what you have here is a site variability funnel plot basically looking at the centers that implanted in the Evolute Low Risk Trial implanted tabbers and on the x-axis here you have an effective permanent pacemaker rate on, I'm sorry, on the y-axis. On the x-axis you have a number of implanted tabber patients. Each dot is representative of a single site and just like all funnel plots basically you have two confidence intervals that are represented by these dotted lines. And so the red line would be out of the bounds then of two confidence intervals and the solid black line is indicative of that mean rate of 17.4%. If you look at the bottom right corner of the plot you'll see my site there. We were the highest enroller in the Evolute Low Risk Trial. We enrolled about 128 of the roughly 1,000 patients that were inserted into that study. And so we were representing greater than 10% of the clinical trial population out of those patients, 65 randomized trans-catharylortic valve replacement. None of those patients had pacemakers coming into the procedure. And we ended up with an effective pacemaker rate of somewhere around 1.5%. And so you can see that kind of dot there. And we're gonna talk more about implantation technique but I think what made our site singular. And if you look at the bubble plots really the entry level of right bundles, pre or post dilation, we were effectively putting the same patient on the table as everyone else was. The same procedural characteristics. It's just that we were using the cusp overlap technique that we'll go over and we use that in every single patient we implanted this valve in. Thank you. So there is obviously tremendous variability between centers and the operators that was totally surprising to me when I saw this knowing that all of those operators were experienced operators and they had plenty of opportunity to pass the learning curve. So obviously it's not just expertise but a particular technique that plays a significant role as far as instance of heart block is concerned and need for permanent pacemaker. Would you agree with that? Yeah, I think that's a very good statement. Tell us a little bit more about your personal experiences related to the need for permanent pacemaker, post diver is concerned and how did you get to this point of having such a low rate of need for permanent pacemaker, particularly when you look at some other experience centers that have significantly higher incidence? We've always been a high enrollee in the Medtronic studies and like this shows we were the highest enroller in the Medtronic low risk trial 65 patients randomized to TAVR. What we found in all of our studies is that our clinical performance is related very heavily to pacemaker rate. And we know that from a variety of different studies that have been done on both the immediate and long-term impact of having a permanent pacemaker after transcathory or valve replacement. Our electrophysiologists are by the book we don't have any same day permanent pacemaker implantations they will want to observe the patient over a 24, 48 hour period of time to watch for return of conduction. And so from a hospital efficiency standpoint and really the underpinnings of the economics of our program, it would behoove us to really move towards a strategy where we could reduce the rate of permanent pacemaker implantation. And so anatomically, this is feasible with the technique that we're about to discuss. But if you look at the anatomy in the right way fluoroscopically as well as institutes and procedural nuances you also can get very low single-digit pacemaker rates. And with the envelope platform there's no foreshortening from the ventricular side. And so that's the reason why this is really our main TAVR platform. We've been able to get these pacemaker rates and of course we have the hemodynamics related to the superannual valve placement. And so here we have a mean length of stay in the lowest trial of under a day and a half with 90% of our patients discharged home the very next procedural day you can see our hard outcomes there and they were quite good for this trial. Which is truly remarkable because we know with this particular TAVR device in very early experiences and early trials the hospital length of stay was significantly lower and significantly higher because of the concern for the complete heart block. So obviously you have achieved something that's remarkable from the point of view as far as need of the pacemaker concern but also low incidence of mortality and need for a basic at the later stage. Now it's interesting from the data that is available from many studies that close to 40% of patients that develop heart block at the time during the procedure or shortly after actually will not necessarily maintain complete heart block after that. So it means that we are maybe implanting pacemakers more than we need to but the issue is how long do you keep the patient and when the ones in safe to discharge the patient. So that certainly is of concern as well. But let's talk about another very important and pertinent information and let's discuss cardiac anatomy and factors influencing cardiac conduction and persistent disturbances during TAVR. And if you don't mind explaining a little bit this anatomy that's so important as far as conduction disturbances are concerned that occur during TAVR. Yeah, it's extraordinarily important to understand this anatomy as we set up the TAVR procedure. And so what we know about the conduction system is the AB node is really on the right atrial slash ventricular side of the heart. And basically then you get a permeation of fibers through the intraventricular septum and they're housed in the membranose septum in the histric and G system to a variable degree of length. There was that seminal paper that came out from NYU just a couple of years ago looking at membranose septum length and its mitigation or enhancement of conduction disturbances based on the length of the actual membrane septum. And so the membrane septum basically houses these fibers that then become very superficial below the membrane septum as you go towards the muscular septum. The non-cornery cusp is the most inferiorly oriented cusp. And so when we're planning our TAVR procedure it would be good to have a reference to the non-cornery cusp, i.e a pigtail at the base of the non-cornery cusp which is great. But equally important is understanding that conduction system which is really below the non-right commissure. So when we set up a view and we set up an implantation technique we're going to wanna see the non-right commissure in the center of the screen. And so this is the anatomic relevance of what we're about to discuss. Similarly as we're planning our procedure we're gonna be looking at calcium burden and the calcium that makes me nervous with regards to self-expanding valves is coronary cusp calcium on the left coronary cusp because the left coronary cusp is basically opposite the non-right commissure. And so it's gonna give you augmented or unopposed radio force if you don't prep left coronary cusp calcification that's significant. And so I think that the anatomy is crucially important in setting up our procedure to avoid conduction disturbances. So maybe you can just briefly mention you didn't mention membrane septum as one of the important factors as far as conduction system is concerned. And this is clear from this particular schematic drawing on the anatomy that it is in close proximity to the conduction system. So does the length of the membrane septum have any importance in predicting where you should place the valve and what is the risk of a conduction system problems occurring after TAVR? We look at the NYU article and at least the procedure that they used to measure membrane septum length and then how they were assessing their depth of the valve deployment. Unfortunately, they had no like core lab CT data that would have given you really what you needed in order to really ascertain whether a membrane septum length was prognostic of conduction disturbances. What we know and intuitively it would make sense that if you have a shorter membrane septum versus having a longer one that your conduction disturbance rates are gonna be quite disparate meaning you're gonna have a higher rate of conduction disturbances with short membrane septum lengths. That being said, if you implant the valve routinely at two to three millimeters below the annular plane most membrane septum lengths are gonna be well beyond that range. And so yes, we're all still going to get some conduction disturbances but shallower deployments referencing the non-right commissure that's really the key focus here. And so I really don't measure membrane septum length I don't find much clinical utility in it but it is something that people are doing and referencing when they're deploying valves. That's a very interesting and important. So how does this information relate to the CTA and angiographic imaging during TAVR? How can you correlate pre-procedural imaging with TAVR imaging or angiographic imaging and how much does it help you in deciding where to place the valve? So what you see here is our traditional coplanar view that we were all taught to use very early on in TAVR days. And basically here we have non-right, left equidistant coplanar. It's our traditional coplanar view that we were taught to deploy basically the sapien prosthesis in but even with core valve and evalute platforms the mainstay of gold standard teaching started with this view. But this view is an anatomic fallacy. All three of these cusps insert in differentially along the left ventricular apolotrack. We had talked about the non-cornery cusp being the most inferiorly oriented cusp. Here, not only is the non-cornery cusp not isolated but you actually are overlapping the non-cornery cusp with the right leading to a complete confounding of your assessment of the non-right commissure. So in this particular view, you're not really going to understand where you're deploying a valve relative to the conduction system. The other thing about evalute is that when you're actually going and deploying that valve you wanna remove parallax out of things, parallax out of a marker band, parallax out of a valve platform. When you do all of that you actually rotate out of the coplanar view. And so really you're then putting parallax into the native annulus and that really is gonna confuse your depth assessment as well. And so if you don't go in with strategy that is isolating the non-cornery cusp, overlapping the left and right, you're really putting yourself at a hindrance of not being able to understand where exactly you're deploying your valve, especially in relation to the conduction system. Very good. So it's important to know that the annulus is not a straight structure but it has more like a sphenoid type of a configuration. And it's like you said, very confusing and actually not helping at all to draw a straight line assuming that this is where the annulus is. Correct. So this gives you an example of parallax. Yeah. So here we have a traditional sapien deployment. So non-right, left, equidistant coplanar, pigtail at the base of the right corner, right cusp. Middle marker of the sapien just above the base of the pigtail. And now we're deploying this valve. And so what you're gonna see at the completion of that deployment is what we call parallax. And so we have a frame, basically reference that those diamonds are not completely superimposed upon one another. So there's some sort of misunderstanding or lack of understanding as to where the depth is in relation to not just the pigtail but any LVOT structure because the frame of the valve is not uniform. And so then because of that cognitive dissonance, we would then move to rotate the gantry to make those diamonds superimposed upon one another. But when we do that, we actually open up the lip of the native annulus and introduce parallax into the native annulus. So you're basically trading one form of error for another in this particular technique and view. Another interesting thing is that it's clearly demonstrated here. And that's unique to this particular valve. How much of foreshortening occurs distally and not much at all above the annulus. So you have to take that into consideration as well. Absolutely. Which is another important factor. And so again, just showing you that whole concept of parallax in that valve frame. And as you click through this, it's gonna be uncertainty as to what the true depth of implantation is. And to your point, if your pigtail is at the right cornering pus, okay, you could probably ensure that your valve is not going to be deployed too low and that's great. But it's really the higher deployments that matter. And so the pigtail, the base of the non-cornering cusp is gonna protect you from being too high. And so you want a shallow depth of deployment, it's better to have a pigtail at the base of a non-cornering cusp. If you want to comment a little bit more on a few of the things that have here. We've got a front side of a cylinder, a backside of a cylinder, and they're not matching. They're not superimposed upon one another. So the whole purpose here is to show you that what this whole concept of parallax leads you to do is want to superimpose it so you find some sort of two-dimensional structure, which is fine. But the problem is that whatever you're doing to remove parallax out of that valve frame, you're doing the exact same thing to put parallax into the native annulus. And so by virtue of doing that, you're just gonna be very confused with where exactly you deployed this valve. So it's pretty standard for the operators that use sapien that you always place a pigtail in the right-cornering cusp, hoping that you will address and resolve these issues, but you're not really resolving it. Correct, and as you click through here, you're gonna see that. I mean, you just are confused with where exactly you deployed this valve. So here is the view that we're going to use. And this is our cusp overlap view. So the non-cornering cusp isolation, left-right overlap, and this is typically gonna shift you in an aureocautal gantry direction. Some people refer to this as aureocusp overlap or aureo technique. The vast majority of the time, you will be in an aureocautal quadrant, but that's not definite, that's 100%. And so as we reconstruct the CT scan, we're really gonna pay attention to superimposing those right and left cusps, leaving the non-independent. And that'll most often be an aureocautal view, but you could have an AP-cautal, aureocautal straight AP view, depending on the aortic and ventricular anatomy relating to one another. How you get here is not rocket science. We're basically doing a traditional coplanar view and then we're just migrating down the S-curve to overlap those two dots, leaving the non-cornering cusp independent. How reliable is pre-procedural CT evaluation in predicting those angles? And how often do you have to modify it? I use my CT as my crutch. So, I mean, I always tell my CT techs to let me know if the patient is unable to lie flat in the CT scanner, if they have to rotate them in any way, that sort of thing, I wanna know details about that because basically the patient's gonna be lying flat on the table during the procedure. That's the one thing where your pre-procedural CT, assuming it's good quality, may not predict exactly what happens during the case if your patient is in a different position between those two things. So here, we see what happens when you start taking parallax out of things. Typically when you do that, you're shifting the gantry LAO and then you're fiddling around with cranial caudal and you're typically ending up somewhere in LAO caudal quadrant. What we know is when you do that, you rotate around the insertion of the left cornering cusp. You raise the right, you drop the non and the non-cornering cusp, because it has parallax now in that annulus, it is no longer representative of whatever fluoroscopy you're viewing here of the annular plane. And in fact, what you're gonna end up doing is underestimating your depth of deployment. And so if you end up in this quadrant at the end of the procedure, simply by taking parallax out of things, you're going to underestimate your depth of deployment on the non-cornering side, as you see here. What about the scenario where you have either severe calcifications or one reason or the other morbid obesity or lung disease or uncooperative patient, you cannot clearly see the cost to achieve whatever you wanted to achieve. So in those particularly, and I would say it happens a vast minority of the time, obviously, so we're talking about something that may happen between 10 to 15% of occasion. The morbid obesity thing is very real. And the reason why that's important is because some of these gantry angles are predicted as very steep. And so say you have a predicted cusp overlap view of RAO 30, caudal 50, you have a large image intensifier and morbidly obese patient, you're not going to be able to get there. So in those particular settings, we use what's called near overlap. And so we migrate back up the S-curve to perform a view that's actually realistic in the lab of attaining. We're not going to have pure isolation of a non-cornery cusp, but it'll be close enough to give you a relative good marker of where you're landing the valve in relation to the conduction system. Those kind of adjustments are necessary, like I said, 10 to 15% of time in our experience. It's not something that most of your cases are going to be just fine with that cusp overlap view going in and deploying the valve as is. Very good. So can you guide us in a step-by-step fashion as far as the implantation technique is concerned to avoid the complications as far as conduction disturbances are concerned? So to put it in text, I mean, this is basically what we're doing. We're overlapping the right and left cornering cusps leaving the non-independent. That's most often an RAO or AP caudal view. The other thing about this view, and we didn't talk about this, but when you have a wire in the ventricle that's of suitable stiffness, and we tend to use the double-curve lunderquist wire in the vast majority of our cases, if we can take a pigtail and launch it into the Apex, then that patient is going to get a double-curve lunderquist. And so we unsheath the double-curve lunderquist in the Apex. We don't manipulate that wire in any way, shape, or form. It basically is unsheathed like you would a PFO or an ASD occluder device when you deploy that. And so basically it's a set it and forget a type of wire. I always deploy it through a pigtail. I don't pre-shape the wire in any way, shape, or form. I let the lunderquist do its thing. What that does is it stands the valve upright along the posterior aspect of the annulus. And so basically the wire then wedges into the non-right commissure. And that actually is going to take parallax out of the ring of the delivery capiter of the evalute. So if you've got a good cusp overlap view and you're coming down with that marker band, expect parallax to be removed simply because of where the wire is positioned. And so that I think is an important facet of this technique that is going to lead to a more efficient and predictable procedure. The thing that we know about cusp overlap is when you overlap the left and right cornering cusps, there will be certain anatomies where you capture the right cornering cusp and miss the left cornering cusp. So there is on purpose a second view that we use where we basically pivot around the left cornering cusp separating out the left and the right and seeing and making sure that we've caught the valve where we want to on that left cornering cusp side. But keep in mind as I referenced in a previous slide, you don't wanna look at the depth in relation to the non-cornering cusp in that view because odds are you're going to appear to be much shallower than you actually are in that specific view. When we reconstruct the CT scan, we're bisecting each cornering cusp and we're going to the true insertion of each cusp. And so you can see here that we're going to be rotating around the annular plane and basically bisecting the leaflet straight in the middle and we're going to go down to the true insertions of each of these cusps. This is a whole 30 to 45 second process on three mencio, but it's invaluable because if you got a good quality CT scan and you're able to do this correctly, it's going to save you a lot of time during the procedure. You're going to march in with that one view and you're going to be able to go to the point of no recapture with your evalute valve with confidence and understanding where you're deploying this thing in relation to the non corner cusp insertion and the non red commissure. So what this is going to walk through basically is the full reconstruction. So we have a traditional coplanar view. We rotate down the gantry to an aria caudal position here. This is an aria 15 or aria 13 caudal 25. And what we're going to do here is basically simulate what this valve is going to look like in an LAO projection. Because again, the second part of that technique when I rotated the gantry LAO, I kind of want to understand how shallow I'm going to look on that non cornering side. And you can see here as I rotate around the left cornering cusp which would remove parallax from the valve platform. I get a decent assessment of where I am in relation to the left cornering cusp which is grossly representing the annular plane. The non cornering cusp pigtail slips below that line. And so you can see here that we're going to imbu an error in this particular example of somewhere around four millimeters. The vast majority of our cases we're going to appear to be shallower than what is really happening on that non cornering side in the LAO pia. So let's start with how you start the procedure. So it's not just about imaging. There are procedural modifications here. And so one of the procedural modifications that we do basically is start higher. And so instead of taking that marker band all the way down to the level of the annular plane and flowering out the valve and pushing on the wire which you don't need to push on a double curve lunder quest again but then pulling back on a delivery catheter creating more of an inter curvature trajectory and maybe even scraping the muscular septum as you do that you're going to impair conduction. And so this is really a top down deployment. We start with that marker band right around mid pigtail and we're going to basically eject the valve down more ventricularly as you'll see on the next slide. And so here we're slowly rotating the handle on the delivery catheter and the valve will naturally start its trajectory down towards the ventricle. The reason why this works is because you have a centimeter of space between the nose cone and the valve that's housed in this delivery catheter, this capsule. And that capsule is pinning back the non-cornery leaflet quite well. And so if you've got a stiff wire in the non-right commissure you got this capsule you got five millimeters of it below the ventricular plane, the annular plane. That's fine. You don't need more than that. And so in most of your 29s and 34s what you'll find is that even position one doesn't even need to exert tension forward the valve is naturally going to dive down into the ventricle. Whereas some of your more calcified 23s and 26s you may need to lean a little forward in order to get the valve to flower down. But we're aiming for a target implantation depth of somewhere around three millimeters below that non-cornery catheter. So tell us about pacing consideration during the deployment. What is your approach? So I love pacing, you know and one of the things about evalute is that you don't necessarily need to pace but just because you don't need to do something doesn't mean that it's advantageous to do it the majority of the time. And so with evalute I think the majority of the time rapid pacing works quite well. And so once I'm up to about the third or fourth node with that marker band and the valve is starting to flower out and I've opposed that non-cornery side I want to create a very efficient procedure. And so if I've got a normal ventricle on a patient that can tolerate it just like they could a sapient pacing run I dial the pacemaker right up to 180 and I go right up to the point of no recapture. When I get up to the point of no recapture it's important that you dial down the pacemaker not just to abruptly shut it off because if you have a lack of calcium on the anatomy unstable prosthesis you can just eject the valve out aortic and with the evalute that's fine. I mean you just recapture and start all over again but again to create a more efficient procedure avoid those exorcistilies you want to dial down the pacemaker pretty quickly. So to go from a rate of 180 to 80 and like 40 beats per minute increments you can do that over a five, 10 second period of time and really avoid those exorcistilies. In patients that can't tolerate it then clearly I don't do it. So yeah, you can look at those patients who have poor ejection fractions bad pulmonary hypertension, critical coronary disease they're hypotensive they're taking care of the problem for you and so you don't need to pace those people at a high rate and so in those patients just to eliminate ectopy you can pace them at 100 or 120 and that'll be perfectly fine but like I said in the vast majority of my patients for an efficient and predictable procedure I get up to the point of no recapture with rapid pacing. Very good. So how do you confirm the depth and performance at what point do you make that decision? You are satisfied or you're not satisfied? I need to recapture and so on. So in the cusp overlap view what's shown on the left panel there is that's the view that we were using to deploy the valve in. And so we basically get up to the point of no recapture and dial down the pacemaker, shut it off and now we are looking at what I would call the left line or silhouette of the valve. Keep in mind that you will have parallax in the valve frame while you're attached to those tabs on the delivery catheter it's important not to remove that parallax because if you twist away and remove parallax you're gonna again put parallax into the native annulus and you're basically going to be assuming the same problem that you're hoping to eradicate. And so here we're just looking at the depth in relation to the left line of the valve. The right view is the LAO view where we're rotating basically around the left corner of cusp insertion. I think the quickest way of doing this is just to open up the aortic arch by rotating LAO off of your cusp overlap view. So if your cusp overlap view is say an RAO 20 caudal 25 I would keep the caudal 25 on and just rotate to about an LAO 25 to open up the arch. When you do that you rotate around the left corner of cusp insertion you basically are going to separate out the left cusp from the right cusp. And so you'll get a very good understanding of where you've landed on the left side. Now again, keep in mind in that LAO view that you're gonna look super shallow on that non cornering cusp but understand that that's not reality. You're not super shallow it's just because of the view that you've chosen to assess the left cusp. Very interesting. So one thing that's important that I have seen a lot of operators while they're deploying the device this particular one, Evoluta that they rushed through it and they don't spend time. The recommendations are that you should wait for about 10 minutes for maximum expansion because if you don't you could have all kinds of issues whether it's AI because the valve didn't expand adequately or several other problems. So yeah, it's important to do all those things to make sure that everything is fine. What's interesting, whenever you go to the LAO and you look at the valve you see that it's deeper than in a non cornering cusp area. And so the question is when you see this and here you can see that the difference could be let's say you have about two millimeters of a non cornering cusp and you probably have around five or six millimeters on the left cornering cusp. What is your decision? When are you satisfied? We're not satisfied. When are you gonna recapture? That's a very good question. And I think that for being differential of three millimeters is not a problem. I mean, the valve is naturally going to correct itself. Now I want to make sure that I'm as shallow as I want to be on that non cornering side because I'm a little deeper on the left and I'm very oversized with the prosthesis. I can expect that valve to write itself by shifting down more ventricular on that non cornering side. And so it's important for me to really understand what I'm doing with that platform. So if I've got a six millimeter depth on the left and I'm like a three or a four on the non I'm totally recapturing that valve. I'm gonna pick it up a couple of millimeters assuming that that cant is gonna play a role. And so, yeah, this is the finesse that's possible because you understand in this technique where you're actually landing on that non cornering side. Now another pertinent question is a lot of operators that feel somewhat uncomfortable in aggressive placement of the valve very high let's say a millimeter or two in certain scenarios. They feel that it's risky. Now, what is your point of view for those that believe in this particular problem? So I will say that people kind of misinterpret what we're presenting right now in that I'm not telling people to deploy a valve at zero. I'm basically telling you to deploy a valve at three just like you've been comfortable doing but actually understanding that you're deploying the valve at three and actually deploying it there versus thinking that you're deploying it at three and actually deploying it much deeper than that. And so that's really the hallmark of this technique. It's just to give you a more accurate assessment of your depth of deployment on the non cornering side. Another question is, do you use the same approach and the same strategy as far as depth of deployment in all the scenarios? Let's say I'll give you a few scenarios. A patient with complete heart block and a permanent pacemaker, would you be aggressive or would you use a more conservative approach in this particular? So I like the wrap of the Evolute Pro to interdigitate with as much leaflet anatomy as I can get it to. Basically what's gonna shut down the paravalvera leak from Evolute Pro platform is the fact that you've encompassed that surface area of the wrap and basically surround it off all those micro channels that would happen with leaflets. And so actually a shallower implantation, I believe and there's more data to be basically studying for this that a shallower implantation is actually paradoxically almost going to lead you to have less leak and obviously improve your hemodynamic performance. But in any case, I'm basically going with the same mantra. I'm aiming for about a three millimeter depth of implantation and the real reason for doing that is the fact that that pro-wrap is going to interdigitate itself better with the leaflet anatomy. If you dip it too far down on the left of the drink or afloat tract, it's not gonna be doing anything for you. Very good. Now, the final step is releasing the valve and maybe you can give you important details. What do you do at that particular time? So we were very quick to get to this point of the procedure and we did our assessments. Now we slow everything down. So the wire is pulled back so it's barely out of the nose cone and we're basically doing a 15 degree turn on the delivery catheter every 10 to 15 seconds. And we're just allowing the valve to expand in that annular plane to a butt the calcified tissue for the night and all to warm up all of those things that will keep the valve nice and stable. We've made a decision as to whether or not position one is going to be leaning in on the delivery catheter or holding steady. In the LAO view, it's apparent what the lie of the delivery catheter is. And so if you're very outer curvature with your delivery catheter and you're deploying very shallow to the left corner at CUS, position one may not need to do anything at all. They may just hold onto the delivery catheter and that's about it. Whereas if you're more inter-curvature and you're very shallow on the non-cornery side in your CUSP overlap view, then maybe position one's going to push a little bit forward in order to stabilize the valve on a non-cornery insertion. But the key thing here is to be very methodical about the release of the valve and really allowing no fewer than 30 seconds to elapse while you're deploying the tabs of this valve. And so it's not just one motion and you're done because that's gonna lead to unintended migration. You're just serially dialing this thing, waiting for those tabs to release one at a time. Some people like to pace during this portion of the procedure. You'll see that here. This is my colleague and friend, James Harvey, who did a procedure with CUSP overlap. He likes to pace during the release of the tabs. I personally do a lot of LV wire pacing. And so in that particular circumstance, my wire is pulled back, so it's not gonna be conducting. I just go very slow. So again, 30 second minimum to release the tabs. So why would you pace in this type of scenario? To eliminate activity, to eliminate activity to stabilize blood pressure, people like doing that sort of thing. Interesting. You did mention that you do like pacing, wire pacing. So you feel like this saves you time and no need for a pacemaker and stuff like this. Yeah, and potential morbidity, I think. And I mean, there's been a nice analysis that was recently published on LV wire pacing. So I mean, I think it's safe. You obviously avoid the morbidity of putting in a temp wire. I think it's very reliable as that study would have shown, but also in our experience, I mean, the LV wire pacing works really well, especially with the Lunderquist wire. And basically we have two alligator clips. We have a cathode, we have an anode. The anode is basically clipped into the sheath insertion site. So one alligator clip basically on the sub-Q, one is on top of the skin. And then the other one is on the wire as it exits out of the delivery cathode, that'll be sufficient insulation for the circuit. Double curved Lunderquist, basically melds very well with the ventricular myocardium. And so you're gonna conduct pretty well. And say you do have a conduction disturbance, just don't pull back the delivery cathode, leave it there, have the wire there. And if you've got venous access, you can put a temp wire in and then switch off your pacing circuit quite easily. But because our pacemaker rate is so low, most of the time LV wire pacing is kind of our go-to. Here we have a recapture. And so basically if you've got a valve that's deployed too deep to the point that we were making earlier, I like to pace during my recaptures as well. Using LV wire pacing, you don't really just completely stunt ventricular performance. And so the valve will actually naturally migrate itself up as you collapse it down to about the third node. And then we go right back up to the point of no recapture. And so you'll watch that again. Basically we're pacing down to about the third or fourth node of the valve. And the valve just naturally migrates itself up with the LV pacing. And then we just go right back up to the point of no recapture. If you're super annular with the valve platform, the base of the valve platform, then clearly you wanna do a full recapture and start all over again. And the previous instructions for use are really what is applicable with how many times you can do a partial but full before they advise you to take the valve out and prep anyone. Very good. So now what we have discussed so far predominantly is on self expanding valves. Is this also applicable for the balloon expandable valves? Yeah, I really like using this technique, same technique for the balloon expandable valves. And a recent publication from Cleveland Clinic on the high deployment technique that they use, which is basically an aria caudal gantry angle with parallax taken out of the valve. We go to a true cusp overlap view. So we're actually very respectful of the native anatomy. I think going to an arbitrary aria caudal view doesn't really serve the purpose that you're seeking here. You wanna be able to deploy valve relative to the true insertion of the non cornering cusp in the conduction system. And so we use the same knowledge off the CAT scan that we used to plan our Evelu procedure. We do the same thing for the sapien deployment. And so the nuances here are that you've got a pigtail at the base of the non cornering cusp and the cusp overlap view. We position that middle marker basically just around mid pigtail and the radio lucent line of the valve just below that pigtail catheter. And that usually will lead to a 70, 30, 80, 20 style deployment. But again, to your point that foreshortening can be unpredictable depending on how oversized you are depending on how calcified the anatomy is what any kind of can't on the valve itself. All of those things matter. And so it's not as predictable I would say as the Evelu cusp overlap implantation simply because of the foreshortening but this will get you reliably shallow implantation depths. I think using this technique. It's interesting that with sapien this is relatively rarely used as far as I'm aware and a lot of operators that use almost exclusively sapiens don't do it often enough. The other thing I'll point to yeah the other thing I'll point to is look at the parallax in the valve frame once it's deployed in cusp overlap assuming you don't have much commissural calcium and you've got the right wire in place look at how beautiful that valve looks. I mean basically the parallax is entirely removed out of the valve platform. Right. So there are certain questions that are always very pertinent related to it. And some of them are how often do you get pop outs and what do you do when you have this? I think that that surrounds the point that you were bringing up with you know what about these shallow super shallow deployments and again that's not what we're aiming for here. So our use of a second valve metronica to actually vet our data and commercially our use of a second valve somewhere around one in 200. And it's usually because of something that has nothing to do with a pop out per se that usually has to do with the fact that we've got like a degenerated homeograph then we're putting one valve in as a scaffold to support the second deployment. We have a non-IFU case with a perimeter of 102. We put 234s in for radial force purposes. All of those things kind of lead to different cases where we could use a second valve that's not really a pop out. But the whole point here is to understand your depth of implantation on that non-cornering side. So again I'll say the purpose of the implantation technique is to tell you something on the screen that you can believe. And so you can believe a three millimeter implantation depth on cusp overlap fluoroscopically whereas in another view you're not gonna understand what your true depth of implant is. So I have personally never experienced that but I have seen many scenarios where this happened. And almost invariably this is related to either some judgment error as far as sizing is concerned. I've seen that in my cuspid valves or patients that have primary urtic acid efficiency and not really calcium at all at the annulus or PVCs or where you didn't lower the pressure enough and all of a sudden you lose control of it. So another scenario which I see that you can prevent this is using a stiff enough wire that supports you and you have a control. And this is where London Quest plays a significant role. So I think those things should be taken into consideration to avoid this type of a problem. And I think here this gets again at the depth of implantation. If you're gonna post dilate really just aim for a three millimeter depth of implantation. Right. So post dilatation it's another potential risk that you might dislodge the valve and you might get a pop out in addition to some other issues that might occur. But so I am not very enthusiastic in post dilatation unless I have some significant issues to deal with either perivalval leak that's not resolving. That's why I like to wait for at least 10 minutes or so or the issues where there is a significant gradient particularly in scenarios where you deal with valve to valve type of issues. Is that your experience as well? Yeah, I would agree with you. I think that our post dilation rates somewhere around 20% of cases and that's usually because it's an insanely calcified anatomy where we've already predilated and then we have to touch it up with a post dilation as well. But that happens like I said, the minority of the time. So I know that you are a proponent of predilating before actually placing the valve. And can you mention what is your reasoning? Because a lot of operators don't do that. And there might be some prudence in your approach and maybe you can discuss this. So I don't predilate uniformly. I would say it's probably about 50% of cases. And the 50% of cases that get predilated are based on calcium scoring that I do of the leaflet anatomy. And so there's a tool on 3Mensio that allows you to calcium score. And I'm not looking at an absolute number. Yeah, I mean if I get like a really large ounce field unit score, the sample volume is like 2,000 millimeters cubed as far as the calcium is concerned, then I'm probably gonna predilate that thing. But what I'm looking at is basically a distribution of calcium as it would relate to the commissures, as it would relate to the leaflet insertions and then also the left cornering cost matters like we talked about earlier. And so all of those things at least visually I can see what type of calcium burden I'm dealing with and then make the educated assessment as to whether or not a predilation would be necessary in that patient. And with self-expanding platforms, yeah, somewhere around 50% I think is a reasonable predilation rate. And maybe a little bit more common in the biocuspid scenarios. Sure, absolutely. In fact, we uniformly predilate all of our biocuspid valves. Right, what about the scenario where you have a concern that the valve is not going to expand adequately, you would take that into consideration as an important factor, right? No doubt. And I think that also relates to the calcium burden and the location of it in kind of adjudicating predilation. Okay, so the last frequently asked question, does this work for Tavar and Savar? Yes, it works really well. We call it post-overlap. And so you're basically overlapping two-stent posts leaving one independent. It's going to be an aureocautal or alleochranial view to choose from. I would just pick the one that is easiest and deploy just like you would in native cusp-overlap, it works very well. Can you measure also some other useful technical tips as far as wire choices and rapid basing is concerned? So like we talked about, the double curved wonderquist wire, I mean, this is something that I really would harp on as being a critical part of this particular procedure and leading to the most symmetric implantations, especially with your larger size valves, like a 34 millimeter core valve XL, you really want that stability of the wonderquist wire. And so I can't mention the attributes of it enough. And I know that people, historically like kind of shun when they hear the word wonderquist, but this is a wire that can be managed quite well and quite appropriately, just like all things you have to have respect for it and you have to deploy it the right way. Use a pigtail cap or be knowledgeable about your native anatomy and don't push forward on the wire at any point during the procedure. Rapid pacing, we talked about this. Basically, I like to do it in the majority of my cases, but again, I understand the clinical situation I'm dealing with with that patient and that's going to modify whether or not rapid pacing is appropriate for a given patient. In general, I say pace at the rate that works for you, but in order to create a predictable and efficient procedure, definitely consider pacing at a higher rate. And then finally, it's all a recipe. There's nothing arbitrary about this as I hope we've been able to discuss during the length of this presentation. I would use all of it, the imaging reconstruction, the gantry view, the procedural steps, the technical features and nuances. I think that's how you get these outcomes of single digit pacemaker rates. Very good. So let's summarize all the important information that we have discussed during this presentation. So really we want best in class permanent pacemaker rates across the board, but in the lowest population, this is especially pertinent. These are people that are going to be living longer periods of time and they're more functional. Pacemakers can be more deleterious in that particular population. So understanding how to deploy this valve is so key, evolut and sapien. And so we can predict the optimal gantry angle for TAVR deployment quite easily on CTA reconstruction as we pointed out. Keep in mind this whole concept of parallax and how important it is to understand its influence on your procedure. And so these are all three dimensional structures. When you arbitrarily rotate the gantry, you're going to shift the relationship in a way that maybe you can't even cognitively ascertain. So it's important to understand the anatomy upfront on that CAT scan and use a predicted gantry view to go in the case and make it efficient and predictable. And then finally, keep in mind that if you do these proper implantation steps and you are going to be very knowledgeable about the anatomy, then you're likely going to get best in class permanent pacemaker rates. And really what you should understand is that you don't want to just arbitrarily take parallax out of things during the procedure. When you use CUSP overlap, you're really sticking in one view for the majority of your deployment. And I think you'll find that to be a very simple, effective and efficient way of doing the procedure. Excellent. Dr. Gada, you are a true pioneer as far as TAVR is concerned in advancing the new techniques and technology and you're bringing science into this procedure that a lot of people think it's pretty straightforward and simple. And it's actually not simple when you look at all the potential variables that can affect the outcome of the procedure, particularly as far as conduction disturbances are concerned and the incidence of complete heart block. And this was one of the major problems and issues with TAVR, particularly in early stages when we're talking about 30 plus percent need for permanent pacemaker. And you have reduced this dramatically to between three to 5%. And that certainly has offered many, many operators to have good results and for patients to have a good procedure and lower risk, particularly related to the conduction disturbances. So we are greatly appreciative for the opportunity to have you in this program and thank you very much for sharing this information with us. Thank you, it was an absolute pleasure.