Yeah, thank you so much, Jay and Sky, thank you so much for inviting me to speak about this topic. Obviously, a very interesting topic to me, and I'm going to try to run through it. Try not to be a whirlwind, but there's a lot to talk about. Okay, so we don't have to dwell too much on CTF definitions, but ultimately, all of these patients, aside from pulmonary angiography, are going to have adjunctive studies like echocardiograms, CT angiography, which is, you're looking for webs and occlusions, and a BQ scan, putting it all together with a pulmonary angiogram, you're then trying to make a diagnosis of CTF. And what you're trying to really, specific for balloon pulmonary angioplasty specifically, you're trying to impact on the histology of what CTF is. And here's a segmental branch in a patient with CTF, and what you're seeing is organized chronic fibrous material in small areas of tiny little channels, which sometimes are occluded with chronic clot, or sometimes are actually patent. What you're trying to do is wire one of those channels and impact the lesion in a way that revascularizes the vessel. So as Vikas kind of already alluded to about the different types and levels of CTF, here's a patient with intralobar occlusion, here's a patient with segmental disease, CTF, and here's a patient with segmental and subsegmental level CTF. And so if you put it all together, you have some disease that starts very, very proximal in the pulmonary artery, and some disease starts much, much further distally in the vessel. And what we're talking about when we're thinking about treatment of these patients, the majority of these patients should be considered for pulmonary endoderectomy, and those really are the patients that have proximal disease, main pulmonary artery occlusion, lobar occlusion. But when you're getting into segmental artery disease, subsegmental artery disease, that's where BPA really kind of shines. But I would also say that we're definitely starting to see more patients, especially those that are not candidates for surgery, in which we have to do BPA on more proximal disease, such as lobar vessels. So what we're doing with BPA is that we're essentially wiring the vessel to the best of our ability and inflating a balloon, and then modifying the plaque. So if you look at histology again, what you're doing is you're engaging one of these channels and you're ripping, you're intentionally dissecting and creating a channel. It doesn't really move, it does not get rid of the plaque, you're not really putting a stent in, but essentially you're doing balloon angioplasty, which is very different from the standard of care that we really do for coronary artery intervention, PAD, where balloon pulmonary angioplasty alone is not adequate. And here's a physiologic example of that. So in terms of technique, there are many different ways to do it, of course. What we usually do for BPA is we usually do femoral venous axis rather than IJ, because we don't want to be standing close to the X-ray tube when we're doing the procedure. We usually use an 035 compatible SWAN to first do a right heart catheterization for all of these patients, and taking advantage of the fact that the SWAN lumen can take an 035 wire, then we can put an 035 wire in in exchange for a longer sheath, which we usually use a 7-inch, 7-centimeter rabies sheath, for example. You can use a slew of different guiding catheters. There is no specific guiding catheter that is specific for BPAs. We're using our coronary guides. And then we're using 014 wires to cross these lesions. Now, there is different operators will prefer different wires. We actually do the majority of our BPA work with FFR wire, believe it or not, even though it really is not meant for crossing CTOs. It's really not meant to cross lesions. It's really meant to be wiring an open vessel, but I'll show you why we do that. We generally try to avoid polymer-jacketed wires so that we're not getting into subliminal space and we're not causing perforation. And as the Japanese experience has shown us, we try to start with undersized balloons to reduce the risk of reperfusion pulmonary edema. We're trying to reduce the risk of arterial injury. So some of the difficulties you might encounter in somebody who has significant RB enlargement and as a result of CTEP, for example, is that sometimes it's very hard to wire from the femoral vein into the pulmonary artery. And so if the swan does not go, this is an example of a pigtail technique where you can navigate a pigtail catheter into the right ventricle and throw, quote-unquote, throw the O3-5 wire, and usually that will salvage the case if the swan will not go. The other thing that happens sometimes, it's not common, but once in a while you really cannot get the 7 French or 8 French guide or sheath up around even if you get the wire down. And so one of the other things that we do a lot of times is we'll take the dilator out and we'll exchange that out for a 7 French pigtail and then drag the sheath over the pigtail. A lot of times that will work. Once we have the sheath in place, we usually put a guiding catheter in and then we perform selective pulmonary angiography using the guide catheter. And the resolution that you get with selective pulmonary angiography when you're engaged in the segmental branch is much, much higher quality than a non-selective angiogram. It really shows you the targets of BPA that you may not be able to see otherwise. So the various guiding catheters as already alluded to, some of the most difficult branches to engage are the posterior branches like A6 in the lower lobe or the oingula or the middle lobe branches. So in those, a lot of times we'll use an AL type guiding catheter. But for the lower lobe branches, you can use a multipurpose guide. You could use a GR4 guide. Some operators will also use a guide extension catheter to try to get more selective if the guide itself does not fit well. Some of the challenges we see with BPA that we don't see, for example, in coronary intervention is that the breathing significantly affects and causes a lot of movement in the pulmonary arteries. And that can cause the risk that the wire will be moving so much that it can cause a distal wire perforation. Same with the heartbeat. So that's the reason to use really soft wires to start. Here's an example of vessel tortuosity. And sometimes you cannot wire the lower lobe branches in passive respiration. You really need to have the patient take a deep breath in to strain the vessel out, and then you can wire it. And if you're able to put on, if the wire is able to knuckle, then you feel a lot better that you're in the correct space and you can form bone pulmonary angioplasty more approximately. Since we're using FFR wires and soft tip wires, a lot of times the wire itself, when it engages the lesion, like for example here, it will not cross. So what you may not be able to see here well, but we usually will use an over-the-wire balloon essentially as a microcatheter to get it close to the tip of the wire to increase the tip load of the wire in that way. And just doing that alone a lot of times will allow you to cause a lesion. Even though we're using significantly undersized balloons, what's nice about balloon pulmonary angioplasty and the physiology of pulmonary anatomy in these lesions is once you restore blood flow, the initial vessel size may look really small and you may feel that you really undersized the balloon. The vessel is actually 6 millimeters. But even if you do balloon pulmonary angioplasty with an undersized balloon, you bring them back a month later, you'll a lot of times see that the vessel grows. And there's a process, there's probably a nitric oxide-based process. So it's definitely a safer option to undersize your balloon first, bring them back, and if you need to, then you can upsize the balloon in the next treatment. Some of the other limitations of angiography is that you may not, and this is not to suggest we're doing OCTs in BPA, this is from a research paper, but just to show that sometimes, for example, in C, in the panel C, you may not see the stenosis at all. And the vessel may angiographically look normal, but may have compromised perfusion. And that's because a lot of times the webbings are not clearly seen by angiography. And you really, for that reason, what we like to do is to do a hemodynamic-guided BPA. So we use the advantage of the FFR wire being able to measure the pressure to engage the lesions past the wire to the other, across the stenosis. And what you'll see here is that proximal to the lesion, your pressure gradient, there's really no pressure gradient that you would expect. Once you pass the wire and if there's a lesion in that vessel, you'll see that the pressure distal to that lesion will drop, and it almost looks like a wedge pressure. And if you engage and you balloon, perform balloon angioplasty, you can restore some of the, you can reduce the pressure gradient. There's data to show that if you restore the pressure, if you increase the pressure on the other side of the lesion to less than 35 millimeters of mercury mean, you're able to reduce the risk of microfusion pulmonary edema. And that's one of the things that we try to target as well. As Vikas already showed, here's an example of somebody who had balloon pulmonary angioplasty. One of the things that we know that tells us that we had a good result is that we have return of pulmonary venous return after angioplasty, which we did not have at baseline. Vikas already kind of went through the lesion types. This is just to show you what OCT of a, what a web would look like. It's just kind of an interesting thing, again, done as part of research. We're not doing this routinely. Or at all. But as Vikas already alluded to, the lesion type really dictates the complication rate. And what we're looking to treat are the webs and the ring-like stenosis. These lesions have the highest chance of having a successful result and have the lowest risk of complications. You have higher risk of complications with subtotal and total occlusions. And those diffusely diseased tortuous vessels really are the ones that you really want to stay away from if you're able to, because the complication rate there is so high. The complication rate there is almost as high as the success rate. So in terms of baseline chemodynamics, when we're seeing some of these patients, they'll have very high PVRs and very high pulmonary pressures. There was one randomized trial prior to BPA had better outcomes than those patients that had BPA up front. So we really tried to get these patients on medical therapy first before performing BPAs. And then in terms of you might be thinking, how durable is it to just inflate a balloon in a vessel and not stent it? Does it actually make a difference in the long term? This is a really nice study done from a large Japanese center, which showed that the post-BPA is the final hemodynamic assessment that they performed prior to the last BPA session in chronic phases 12 months out. So all BPAs are done. They reassessed all these patients' hemodynamics afterwards, and they were able to see that the improvements that they saw in the pulmonary pressures, the PVR reduction, the six-minute walk distance have all stayed durable after 12 months. So inflating a balloon in these vessels does seem to work well. And the survival was acceptable. This was not a randomized trial, but it was better than a historical group. And then just the final thing that I'll share is our temple experience in the last minute. This is from August 2015 to May 2022. So again, using hemodynamic guidance, this distribution of procedures that were done, the number of procedures that were done on the patients, you can see most of the patients have four or less procedures. We had a significant improvement in PVR and six-minute walk in distance. And a lot of these patients do have significant improvements in their functional status. In terms of complications, we saw that about 4% of patients had hemoptysis. We had one death that was related to a profusion pulmonary edema. All right. I'm going to skip through this case in the interest of time and take any questions that you guys may have. Thank you.

balloon pulmonary angioplasty

chronic thromboembolic pulmonary hypertension

CTEPH

blood flow improvement

segmental and subsegmental artery disease