Thank you for the invitation to this meeting and what I'm going to present is a bifurcation instant resterosis. So the patient is a 58-year-old gentleman who had angina and then he presented this time with angina and his past medical history include diabetes, he is a smoker, and four years ago he had ACS and at that time had PCI to the LAD and diagonal branch with DK crush technique and he had stent from circumflex artery and to the obtuse marginal branch. I'll show you the result of that procedure so we can see the LAD diagonal bifurcation stenting on the right side. At that time he had 3.5 stent from circumflex artery and to the obtuse marginal branch and that was the result that was four years ago. And then after that, one year after that, he had a PCI to the circumflex artery bifurcation that we don't know the details of it, what was done, what kind of a bifurcation technique used, and now he's coming with angina and LV dysfunction, 35% ejection fraction. Thread mill test was positive. And this is his angiogram now, we can see the LAD diagonal bifurcation stenting is fine, but if we look to the ostium of the obtuse marginal branch, it's really tight. And if we look carefully to the stent enhancement, we can see lots of metal at the ostium of the obtuse marginal branch. So I'm not sure what was done, did they crush the initial stent to the side? I'm not really sure. So we did an OCT, I'll just go back straight to the bifurcation. So this is the stent from obtuse marginal branch, well expanded. And as we come to the ostium, we can see maybe there is some new revascularization here, and most probably this is neoarthrosclerosis with some lipid deposition in that plaque. So this is the narrowing, and this is the bifurcation. So that's what we were dealing with, and minimal luminal area was 1.6. And if we look to the stent, the stent itself is 3 millimeters, and it was 3.5, but what we measured here is 3. So what I believe here is it's combination between neoarthrosclerosis and stent under expansion. The question, how to treat this? That's great, Cal. Shall I? Yeah, so I think by way of summary, you've got a relatively well-expanded stent with material inside it. Is that the way you read the OCT? Yeah, I think it's neoarthrosclerosis, and the stent is not really fully expanded. It was supposed to be 3.5, but now it is 3. So it's a combination between mild under-expansion and neoarthrosclerosis. Great, and I think I was struck, I'd be interested in your thoughts, Khaled, by the volume of neoarthrosclerosis. There's a lot of material inside that stent. Yes. Great. Evan, what do you think you do in this case? I agree, predominantly neoarthrosclerosis is a major problem, and it's mostly non-calcified. I think right off the bat, that kind of takes IVL off the table or any of the arthrectomy devices for appropriate lesion modification. With this, I would go with, going back to the last case, something like a Wolverine, sculpting, scoring, cutting balloons, I think you'd be able to get pretty significant plaque modification here because it's mostly soft plaque and really just creating the cuts and then follow that with an NC balloon. I'd start with that, repeat imaging, and then go from there. Yeah, and the one thing we don't talk a lot about when we review these cases is all ISR tissue is not the same. We already highlighted on the pain point of calcific neoarthro. I think Khaled nicely pointed out there seems to be some lipidic stuff in there. So these are the ones which may be more, I've heard you and Ziad call this more like granulation tissue, Evan. These are ones that might respond okay to ballooning as opposed to needing to be debulked in some way. And so as the neonatal tissue gets brighter and then gets more calcified, its response to balloon angioplasty seems to be less favorable. So what did you decide to do, Khaled, to deal with this? So actually, I did exactly what we just talked about. We did tatting balloon through 0.5 by 10 to the osteum and then followed by a high pressure balloon, 3.5 by 10 OPN balloon. I finished with kissing balloons that are coated balloons. Then I did imaging again. So geographically, still there is a waste into that stent, but we did an OCT, and I'll show you the same area that we were looking at. So this is the bifurcation, if we go back to the osteum, and that's the area we're looking at. So basically, the stent became bigger, the luminal area became bigger, and you can see that new atherosclerotic plaque is ruptured now. So more lumen, bigger stent, and we had laser in the hospital. We could use it, but we were happy with this result. Yeah, so you'll see what appears to be cuts from the atherotomes in the neo-animal tissue. It's kind of cool, actually. No, I think this is a cool-out technique. That's where the cool-out looks with a single kissing balloon, and the bifurcation looks pinched like that, but I think that's the reason why it probably reached to now, it's more than anything else. Sometimes when you do OCT after that coated balloons, we could see the drug inside the vessel. So you can see it like bright spots on OCT. I'm not sure if any of you have seen it. Yeah, we've been observing that as well, but here, so nicely you see those cuts, and that's what we almost every time with OCT, you do cutting scoring balloons, you see the compression of the plaque and then those nice cuts, which, you know, again, there's no data to support this yet, but I think with increased surface area, potentially it may help efficacy with the drug-coated balloons. Yeah, so I have to question as we're on this topic to the panelists, will the blade of the cutting balloon get stuck inside the ISR? What's been your experience, Ron and Evan, with that, is that a problem? It rarely happens, but I would keep it simple. I think I like the fact that you introduced the OpenNC, I think we could have used it also in the prior case. It's a little bit underutilized, but it's a very powerful device. If you know how to use it and on which wire you use it, and it's expensive with no reimbursement, but it's a very powerful device. I don't think that in the case of lipidic plaque, you'd not necessarily need a scoring balloon. You can do well with just a high-pressure balloon. One thing which was surprising for me that when you see neo-atherosclerosis, you don't see much distal embolization of the lipidic plaque, which you see in de novo. If you go after the novolipidic content of plaque, you may see some dislodging of the lipid go downstream, but you don't see it much with neo-atherosclerosis, so there is some distinction between the two. But overall, I think the approach of ballooning it, with or without scoring balloon, I don't think you need one here, because it's not going to be watermelon seeding, and then followed with DCB would be the right approach. And then the only thing I'd add is just with the OCT, you see the stent struts are nowhere near the luminal surface, so that's with no concern whatsoever that the blades would get caught in this, because the stent struts are nowhere. You see, even after plaque modification, you get nowhere close to it, and that's – Kevin mentioned in the last case sometimes of using arthrectomy off-label. If you do imaging and you see there's calcium within the stent struts and there's no exposure to the stent struts, it's safe to do arthrectomy, even though it's ISR. Whereas if you see it's just under expansion, there's no neoendymal tissue, and it's a stent strut with calcium behind the stent strut, and all the mechanical arthrectomy is going to do is just ablate the metal struts, and that's really where the imaging shows you exactly what treatments are appropriate. You know, I was just in Korea seeing a very interesting device. This is a high-pressure cutting balloon. So not a regular cutting balloon, it also has the blades, but it also can go to high pressure. And, in fact, Antonio Colombo takes the current cutting balloon also to high pressure to maximize the effect. But I think a dedicated device – this is all off-label – but a dedicated device that probably will be in use within a year, high-pressure cutting balloon makes sense in situations like that. Yeah, off-label, a Wolverine can go to 24, 25, and have a reasonably low rupture rate. They wrap very, very poorly. So if you've put a guideliner down to get it in, in the bigger sizes, you often have to take the guideliner out with the balloon if you've over-inflated it. But I agree, Ron, it can be useful in those scenarios. So the other thing, Cameron, is the drug-coated balloon should not be used to – for expanding a vessel. It should be just inflated enough to touch the intima. Some people use it even to go to high pressures, and that's not the aim of using drug-coated balloon. You have to prepare the vessel with high-pressure balloons before and use the drug-coated balloon just to touch the walls. And it should be your final step. You shouldn't do any more dilatation after that. That's my understanding. Yeah. And there was actually a question that people asked, if you use drug-coated balloon through a bifurcation with stenting, are you scraping some of the drug, or are you scraping some of the excipient? And there was a bench testing that was done, I think published this week, showing that actually you lose very little drug by going through a bifurcation or through a sterilized segment. But, Cameron, I agree with you 100%. Do all the vessel preparation. The drug-coated balloon is just the final touch. Yeah. And a lot of these DCBs were inflating at six atmospheres. You're not going to get plaque modification there. You should never discover that the balloon's not expanding with the DCB. If you do all these other plaque modification prior to, you'll know whether or not you're getting that expansion. It's just painting. It's the final coating, essentially. There's been a couple of questions in the chat which have a common theme. The first is, if stent at the ostium is 3.0, is it safe to use a 3.5 cutting balloon? I think Colin had made the point that he had anticipated the artery should have been 3.5, but the stent was only 3.0. And then it's been asked, how do you differentiate between stent under expansion versus positive remodeling post-stenting? Maybe I'll let you take that one, Evan. It really depends a little bit on whether you're using IVUS or OCT, and it's not a single frame you look at. You look around. But how do you determine if it's under-expanded, Evan, just from a practical, I'm using OCT, this is how we do it, I'm using IVUS, this is how we do it, versus the stent was 3.0, it should have been 3.0, and now the media is larger because of positive remodeling happened after stenting. Sorry. I was muted. Sorry. I was muted. I think from any one cross-section, you just can't tell. And that's where it's key, just looking at the whole vessel pullback. IVUS has a depth advantage compared with OCT, so you can really see the, most of the time, you'll see the true vessel size throughout. And now with deep OCT, you can often see the true vessel size, but typically it's just going distal beyond that, and you can follow that through and get the vessel sizing? It is very simple. You just have to look at uniform expansion across the longitudinal zone of the stent. And when you see that, you can see that it's actually under-expanded to a certain area which relates to the reference. So we know it's under-expanded. And usually you see calcium or the reason for under-expansion. But sometimes you see recoil of stenting because there is a push of neo-intima formation from the outside. So I would call it exactly under-expansion. I would call it recoil, especially you may see it in ultra-thin struts, and that's maybe a misnomer to call it under-expansion. It was just a recoil of the tissue, of the struts, because of extra struts pressure of tissue. Yeah, so stent scaffold failure, as Ron is nicely alluding to, can be a cause of why the struts seem like they don't fit the artery size. And we've all had cases where we've got a beautiful OCT or Ivis that we did years earlier, and now the stent looks terrible. And you go back and look at your original run, and you're like, hey, I didn't do such a bad job. The stent's not doing its job of holding the artery open. So Colin, go through your... Oh, sorry, Ron, go ahead. No, I said the nice thing, they all can manage with just high-pressure balloons. So it doesn't really matter. And I think that, look, for me, every ISR, no matter what is the mechanism, before you apply DCB or brachytherapy, you have to end with high-pressure balloon. That's like a must. And that will take care of all those concerns. And if after that you still see that it's under-expansion, so you have to make sure that it's not mixed with malapposition or not a full apposition. So expansion has to be rounded and has to be symmetric across the stent longitudinal plan. Under-expansion, or malapposition, could be mixed up with under-expansion. It's a completely different thing. And we don't have to try for full apposition. Great. So Colin, show us how things resolved. So the minimal lumen area from 1.65 to 4.9, and the stent was expanded from 3 to 3.75. This patient came back after three months with atypical chest pain. So we thought, well, we'll just have a re-look. You can see the angiographically from the spider view, it looks fine. Then we did an OCT. This time it's ulterion, so we have, I think, to go from here and back. So now we're coming from the OM, going back to the ostium, and then we'll see how that dissection healed. And you can see this is the area that we treated. So this is the one then, see, that's the bifurcation, and this is the area that we treated. Now it healed with neoentimal hyperplasia, and that's what we have. Lumen is 3.55 square millimeters, and then we did RFR, which is 0.98 after three months. So this lesion healed nicely here, so we left it for medical therapy, of course. Just a few points with instant restenosis and bifurcation. I think knowing the technique that has been used in the past helps you to plan your strategy. So then most of the times you have to maintain the same bifurcation technique that was done before by wiring both sides and finish with kissing. I think imaging is mandatory, and instant restenosis and bifurcation, to know what's the mechanism and to optimize the result. And avoid additional stents and bifurcation as much as you can. That's great, Khaled. Any comments on that? It's been discussed a little bit so far. Thoughts, Evan, Ron, John, or Patrick? Definitely avoid another stent in any of ISR. I think there is no point to put another stent. I think that even for the first layer, when you're tempted to do it, you probably should have a very good reason to put another stent there, especially if you have DCB today. So I would say sometimes you need, but if you can avoid it, avoid it. The first go-around should be, right now in my perspective, POBA, vessel prep, and DCB.

neoatherosclerosis

DK crush technique

drug-coated balloons

restenosis mechanisms

interventional cardiology