Chapters Transcript Video The Eye(VUS) Cannot See What the Mind Does Not Know: The Use of and Case for Intravascular Imaging in Modern Coronary Intervention Dr. Kerrigan describes the studies that have shown the clinical benefits of intravascular ultrasound guidance for complex coronary intervention(PCI). Jimmy Kerrigan, M.D.University of Tennessee Thanks for the opportunity. Thanks for uh a chance to come visit the Norfolk area and talk about something that is really near and dear to my heart with regards to how to do PC I but how to do it as well as we possibly can. There we go. All right, my disclosures, uh some of which are relevant for this conversation. So as cardiologists generally speaking, we like data, we like guidelines, we like guidance on how to do the things that we are here to do. The most recent revascularization guidelines were updated in December of 2021 from the AC cah A standpoint thinking about things that we do. There are current class one recommendations for revascularization in the guidelines. As a few examples, we're to use a heart team when it's not completely clear how to revascularize patients prior to sending patients for bypass surgery. Calculation of risk scores to risk stratified patients are recommended a class one guideline for patients who come in with a semi and cardiogenic shock. We're supposed to revascularize those patients in order to improve outcomes for those patients for patients who come in with a stem and have a mechanical complication. Bypass surgery is to be used in preference to PC I for these patients. Again, a class one guideline for those patients who come in with a non ST elevation M I and are appropriate for revascularization with cardiogenic shock. We're supposed to fix them in order to help improve outcomes for these patients. For patients with stable ischemic heart disease. The chronic coronary syndrome patient who has multivessel coronary disease, especially with an ejection fraction, less than 35. Thank you. Revive BC is cabbage is now recommended to improve survival. PC I is not. And then for patients with left main stenosis, we're still to preference bypass surgery in order to improve survival for our patients. But what's interesting is in these guidelines, there's not much guidance on how to do the interventional procedures from that standpoint. Looking specifically at the guidelines and again for those on the line and in the room who uh are in various levels of training. A class one guideline means that we should do this unless there's a compelling reason not to. Class three guidelines, don't do that unless you absolutely must or class two is do it if you want to. If you look at the guidelines from 2021 with regards to revascularization, all of the intravascular imaging guidelines in the United States are either class two A or two B, which means that you can do this if you want to, but it's not absolutely mandated and necessary. And I would pause it. Hopefully, over the next 30 to 45 minutes, we can talk about becoming more European like as a guideline uh group because uh in the guidelines that were released last week is now a one day recommendation for the use of intravascular imaging. Also a question to be discussed is, does it matter as much for the patient on the left where you have complex coronary disease? A left main CTO as it does for the patient on the right, a young woman with a non stemi and a relatively straightforward diagonal stenosis as well. So we'll talk about data, we'll talk about a few cases for the interventionist in the room and online as well to just uh have some practical conversations about how to use this information to manage our treatment strategy for these patients. And then again, those of you that know me div and others, I'm conversational and relatively casual. So please feel free to bring up any questions. Uh Amy is monitoring the chat as well. So please feel free to use that online if uh anything comes up. So looking at the rates of utilization of intravascular imaging in the United States, this data was published in 2020 somewhere between 10 and 20% of PC I done in the United States historically, has been done with the use of intravascular imaging. And again, I would posit that potentially we should be more Asian like from that standpoint. And we'll go through the data from outside the United States with regards to intravascular imaging utilization and rates. So as we talk through a lot of data, I think it's important to discuss what are the definitions of the outcomes of the data sets that we're going to talk through. So looking first at target lesion revascularization after doing a PC I and the patient comes back, do I need to do something to fix that stent or something at the edges of those stents within five millimeters of the edges? And that's target lesion revascularization, an important outcome for these trials. In addition, we'll talk about target vessel revascularization. Maybe I stinted the mid L AD but the patient comes back in six months and has a proximal or distal stenosis, a diagonal lesion, something else that's in that vessel that may not be the stent, but that includes the TLR as overall TV R stent thrombosis. Did the patient come back and have a definite thrombus on intravascular imaging or angiography or based on history? Did they have a thrombus that maybe we didn't quite get them to the Cath lab in time to know for sure, myocardial infarction, the definition of a heart attack or an M I varies depending on trial. Usually it's some combination of ecg troponin. I don't know if y'all still use CKMB. We don't but some biomarker level as well. Death is a little bit of a less variable binary outcome in most trials. Uh and then mace so major adverse cardiovascular events is the combination of some of all of these including also potentially heart failure hospitalizations. So those are just the baseline definitions that we will talk through various trials that have looked at the use of intravascular imaging to determine whether or not it truly matters. And I'll limit the conversation to the drug loing stent area era. There are several trials from the PTC A era and the bare metal stent era that I didn't want to muddy the water with because those were a little bit more variable in outcomes. Maybe not because of the imaging, but because of the technologies we were using and we can talk about drug coated balloons and not stinting. I guess what's old is new again. So Home Des Ibis was a study from 2010, 210 patients who are undergoing complex PC. I were randomized. 1 to 1 half of them got Ibis guided PC I, half of them got angiographic guided PC. I meaning we look at the screen say that looks like it's about a 25, about 23 millimeters in length and go with it to determine which of those two was better in this study. Back in 2010, they wanted to focus on patients that they considered to be complex. So type B two and C lesions left mains, proximal L A DS, small vessels that they defined as less than 2.5 millimeters long lesions, instant re stenosis diabetics and acute coronary syndrome patients were the ones included in this initial trial success in this study was defined as good stent apposition. Meaning that the stent struts touched the wall of the vessel. You didn't have stent struts floating in the middle of the vessel, you had a minimal stint area greater than five square millimeters. So on Ibis, as we pull back, we find the spot where the vessel is the smallest and we calculate that area on foss and we'll go through some examples of that and you want that to be at least five square millimeters or in a smaller vessel, 90% of the distal reference lumen, we'll talk about what that means. But what I wanted to say is if it's a smaller vessel where the distal vessel is only two millimeters, you don't want to go for five millimeters and rupture the vessel, you want to make sure that there's no edge dissection within five millimeters of the stent edges. And then this didn't have a geographic miss component, which we'll talk about as well. What that means. So what was found in this study is that the use of intravascular ultrasound significantly increased the size of the balloon and the pressure of the balloon used for post dilation, unfortunately. And interestingly, but we do see this in other trials as well. The use of intravascular ultrasound led to longer procedures with more X ray time and higher contrast utilization. Nowadays, we use intravascular ultrasound to minimize contrast and do procedures without contrast. But in the early experience, there was more puffing going on as well. Also keep in mind that these were first generation drug alluding stents, 65% taxes, 35% cipher stents, which were associated with higher rates of stent thrombosis and heart attacks. Compared to the current third generation stents that we u to use today. Small numbers. But what was found at the end of 18 months is that there was no significant difference in outcomes for patients when looking at mace. So those bad things happening to patients death, heart attack, target lesion, revascularization and stent thrombosis. Although numerically, there was a reduction in the rates of M I and stent thrombosis for these groups. The authors that based on the numbers of patients in these studies that they would expect to need to enroll 3000 patients, not 210 patients to see if there truly is a difference. So again, 15 years ago, this was a randomized controlled trial but a potentially hypothesis generating study to say maybe future work is needed, which has been done over the subsequent 14 years. All right. So moving forward a little bit three years to adapt des which was not a randomized trial for IVIS, but it did have a component where there was a pre specified analysis. Does IVIS matter? So you have 8665 patients enrolled in this study at high volume centers with expert angiograph. 3300 of them got IVIS guided PC I. The balance had angiographic, guided PC I. And what was found at the end of 12 months was that the patients who had ibis guidance had a 47% reduction in stent thrombosis, a 33% reduction in myocardial infarction and a 33% reduction in overall mace. What was also interesting is that patients who got IVIS guided PC I were less likely to bleed and as expected, less target lesion and target vessel revascularization can't fully explain the bleeding difference. And you can see on the Kaplan Meer a little bit small here and I apologize that those curves separate early and that you have a benefit from day zero. And that persists all the way out to month 12. And on several of these curves, they continue to separate. And we'll talk about later studies that go out to five years where you see those separations and determine whether or not that's significant but again, not randomized data. What was important from Adap Des though and keeping in mind that these are expert angiograph who have been doing this for a long time, 74% of the time they changed their strategy. If you had them write down what stent. What balloon, what post dilation pressure you were gonna go to and put an in sealed envelope like Johnny Carson, nobody in the room remembers Johnny Carson. Um uh the talk show host from way back when anyway, 74% of the time they change their strategy. So just looking at the angiogram saying that looks good enough, generally speaking, was inadequate for the majority of the patients that we were treating uh across these 11 sites in the United States. So the use of intravascular imaging changes, strategy and changes management usually by going to a higher pressure balloon, adding another stent because you missed the lesion or treating under expansion in Malas position at the time of two year. Follow up again, non randomized data, but published as we talked about, the curve started to separate at one year. Uh We're statistically significant at one year and continue to separate uh further throughout the rest of the two year follow up. So now stent thrombosis, a greater than 50% reduction, a nearly 40% reduction uh in M I and now a statistically sig significant reduction in the chance of our patients dying keeping in mind. And this becomes a theme throughout some of the future trials. When we do PC I for stable ischemic heart disease, for patients coming in from home, going to hold and getting their PC I and going home the same day or the next day by and large outside of the left main, we're not improving their mortality, that's for symptom relief. And if we are doing it without imaging guidance, potentially there's harm because the use of imaging guidance improves mortality for these patients as well. Another small study from 2013 Avio randomized 284 patients. Now back to a randomized control trial to complex PC I using IVIS guidance with 100 and 82 and geographic guidance with 100 and 79 they defined complex PC I as CTO S uh patients with bifurcations, long lesions, small vessels and the entire L AD which was considered high risk. At that point. As we saw with prior trials, patients who got IBIS got to PC I ended up getting larger stents, longer stents and higher pressure balloon dilation in the uh study overall. Though what was seen is that patients who got Ibis guided PC I had a larger stent Luminal diameter when all was said and done. If you compared the MLD the minimal Luminal diameter in the group getting angiographic guided PC I, it was 2.5 millimeters, 2.7 millimeters for the patients in the IVIS guided PC I, which was statistically different and significantly larger for the intravascular ultrasound group. Looking at 30 day and overall 24 month mace as well, not statistically significant from an overall mace standpoint between the two groups. But there is a numerical reduction in the rates of MITLR TV, R and cardiac death for patients who got Ibis guided PC I versus just doing it the old fashioned way of looking at the angiogram. Again, the authors note that need future studies, larger studies in order to determine if there really is a true difference which again derived future trials that we'll talk about in a few more slides. 2015 air CTO was another randomized trial of 230 patients who were randomized to angiography, guided PC I versus imaging guided PC I with 24 month follow up. So the primary outcome for this is a CTO trial was late lumen loss. So if I do the PC I, how big is the vessel? And then if I come back at 24 months and repeat the angiogram and repeat the IVIS, does the vessel get bigger? Does it get smaller? Is there any significant difference between that? And then also an exploratory mace outcome and looking at the sub components of mace patients having heart attacks, dying and needing to come back for additional treatment as well. So what was seen in the study is that the use of intravascular ultrasound led to bigger stent expansion with better stent symmetry with a larger minimal stent area. So 4.37 versus 5.92% with the use of intravascular uh excuse me millimeters with the use of intravascular imaging. Also, again, the exploratory end point at the end of two years, there was a statistically significant reduction of stent thrombosis with the use of intravascular imaging from 6.1% to less than 1%. Another study from 2015, I guess a couple of different groups wanted to look at ibis and the use of CTO uh using second generation drug leading stints was published by a Korean group in 2015 for CTO Ibis. So again, 402 patients with CTO S, half of them got IVIS guided PC I, half of them got angiographic guided PC I. What was found at the end of 12 months was that patients in the IVIS Guided Group had a statistically significant reduction in overall bad things happening to them. With a 65% reduction in mace, 100% reduction in the rates of cardiac death, myocardial infarction and stent thrombosis target vessel revascularization was less, meaning the patients were less likely to need to come back to the lab to have something done. But that did not reach statistical significance. And this is interesting because a lot of the other trials that we'll talk about and have talked about. The main difference is whether or not patients have to come back to have something else done, not necessarily benefits and heart attacks and mortality. CTO at IVIS was different showing that benefit early on for the complex patient. All right. So moving ahead a few years, a series of larger trials came out between 2018 and 2020. So the ultimate trial is one that we reference quite frequently because it was one of the first large scale randomized control trials for all comers, not just complex PC I but type A lesions patients coming in from home patients coming in with acute coronary syndromes. 1448 patients were randomized uh in China to either IVIS guided PC I versus angiographic guided PC I. And as I mentioned, this is an all comers trial. So this helped us figure out whether or not it matters for those more simple and what we would consider straightforward patients. So the criteria for optimal stent deployment and this is what we teach our fellows and when we teach new interventionists on how to define whether or not you did a good job. What we're looking for on that stent is making sure it's well expanded. The smallest area inside that stent on I is greater than five square millimeters or in a smaller vessel. At least 90% of what the distal vessel size is. Now, we wanna look at our edges and make sure that we're in an area with less than 50% plaque. We know that if the edge of our stent is in an area with significant plaque that increases the chances of a stenosis at that edge and needing to come back and have to work on that or within five millimeters of those stent edges. And then when we're done, we wanna make sure that there is no tear in the blood vessel, no dissection with that's over three millimeters long at the stent edges as we use other non IVIS modalities OCT which is light based. We find that very frequently, we do have small tears at the edge of the stent. It's prognostically not significant unless it's long or deep and we'll talk a little bit about that as well. So, looking at the patients who got Ibis guided versus angiographic guidance, what was important to note as we've seen in trials before? This is that patients who got Ibis guided PC I receive longer stents, larger stents in diameter, higher post dilation balloon pressures and larger post dilation balloon sizes. And in this study, it was mandated that after you do your stent, say you use a 30 stent, you have to go back in with an NC balloon at 1 to 1 at at least 18 atmospheres of 30. So all these patient got high pressure post dilation. But even beyond that, using the astra vascular ultrasound patients got either higher pressure or larger balloons because we realize that sometimes that's not completely adequate. Again, there was a longer procedure time with more fluoroscopy use and a higher amount of contrast utilization in this study as we've seen before. And again, hopefully, we're getting better with that as we move forward at 30 days, uh there was an early trend towards improved outcomes. So for these next few slides, yellow is trending the right direction but not statistically significant. Pinkish reddish. Uh I only have like eight colors in my crayon box, but that's OK. Uh It is something that is statistically significant. So at 30 days within that first month, which is important from the administrative standpoint because there are financial penalties to the hospital. If a patient comes back in that first month, there was already a reduction numerically in target vessel and target lesion failure. So needing to come back in and have another procedure on that vessel that we just worked on all cause death and stent thrombosis. But more importantly, what was found and published uh at in 2018 was one year outcomes. So in the group of patients, again, 1448 patients, there were 60 events between the two groups, there was 39 episodes of target vessel failure in the patients who had angiographic guidance. 21 in the patients who got ibis guided PC I which was statistically significant. So a 47% relative risk reduction of target vessel failure, which was driven by target lesion failure. So at one year, what was found is that the use of intravascular imaging reduced the chance of me needing to go back in and fix that stent or something at the edges by and large. There is a trend towards less stent thrombosis. But at the one year time horizon, that was not statistically significant. Looking at the Kaplan Meier curves, you can see like we've seen with prior studies that starting at day zero, there is a benefit that continues to expand over the course of 12 months. Again, a 47% relative risk reduction in target vessel failure using IVIS guidance for PC I, looking at death rates, it's a non significant reduction but the use of Ibis guidance is not harmful uh by any means uh at 12 months, not statistically significant but numerically improved. Similarly, for target vessel myocardial infarction, a patient coming back in with a heart attack with biomarkers or ECG changes numerically less chance of having a heart attack for these patients but not statistically significant just overall due to low numbers at the end of a year. Another question that arises at times as we've seen in some prior trials of complex PC I with CTO S bifurcations left Mains et cetera. Does it matter for that patient? I showed you with a type A lesion in her diagonal. So, out of 1978 lesions that were assessed 326 were simple were type A or B one and the balance were two B or C or B two or C lesions. Looking at complexity. There was a numerical reduction in target vessel revascularization and target lesion revascularization in the simple patients just the same as there was in the complex patients because of smaller numbers, no statistical significance was achieved in either of those, there was a reduction in stent thrombosis as well. So overall the message from that is it does matter for the complex patients, but it also matters for that straightforward mid RC A type a lesion that you would otherwise just put a 30 stent in and then send them home later that day. So there is a benefit to the use of intravascular imaging numerically for those patients as well. So looking at it graphically red is ibis guided PC I blue is angiographic guided PC I. These are the simple lesions. There was a numerical reduction in bad things happening to those patients over the course of 12 months. Similarly, for the complex lesions, the lung, the atherectomy, the bifurcations, the things that uh are potentially a little bit more interesting for us in the Cath lab, maybe less. So for the techs and nurses uh in the room, does it matter if you do a good job? I think saying that out loud sounds kind of uh straightforward or or silly to say, but this was an analysis from the study as well. So if you did optimal PC I and achieved all three of those criteria, again, the edges in less than 50% plaque, no edge dissection, more than three millimeters in length and a well expanded stent. So greater than five square millimeters or at least 90% of the distal vessel. What was found at the end of 12 months is those patients had a 1.6% chance of coming back with an issue that needed to be treated if you did the ibis. But you didn't achieve those criteria. The chances of that patient coming back were over 4%. So based on this, it's now recommended that we do intravascular imaging before stenting so that we can go in, figure out our distal and our proximal figure out in between. If we need to do plaque modification, we'll talk about how to decide that and then potentially do ibis again after pre dilating and plaque modifying to make sure that you fractured the calcium and your stents gonna expand and then repeating the imaging after the stent is in to make sure you've met these three criteria. The majority of times we missed on the criteria because we're not fully expanded. And all that takes is a higher post dilation balloon pressure to achieve that in order to move patients from this curve to this curve and hopefully help keep them out of the hospital predictors of getting optimal PC I versus sub optimal PC I. Patients who were older patients who were hypertensive diabetic multi vessel disease or calcified patients were more likely to get inadequate PC I. Again, recognizing a lot of this, especially the severe calcification, which may not be visible on the angiogram or the diabetic patient where the landing zones may not be clean. Those of you who do IVIS in the Cath lab note, when you put the ultrasound down some of these vessels, there's nowhere that's less than 50% black burden the diabetic patients, the long standing familial hyperlipidemic and potentially a patient where PC I might not be the best answer. But these were predictors for getting suboptimal PC I in the ultimate trial. All right. So I said, I'm gonna hammer this a little bit because this is what we're looking for on the ibis after we're done or the OCT. So again, optimal stent deployment in the study defined as less than 50% black burden at the edges and edge dissection less than three millimeters in length and then making sure that our minimal lumen is at least five square millimeters or 90% of the distal referenced lumen. So looking specifically at a case of this, this is from the clinical study. So this is a pull back in an L ad uh from a practical standpoint. And the authors went to the distal reference trying to find an area with less than 50% blackbird and here 19.6%. And what we calculate is the average lumen diameter and the average vessel diameter. So I personally like to draw circles and let the computer calculate the minimal and maximal and then calculate the averages from that some people like to do lines and try to see this is the minimum and the maximum when we're talking about device sizing, you can take the vessel diameter in size down. So this is 3.1 millimeter vessel which would be a 30 distal device or the lumen in size up. So 2.8 millimeter average becomes a 3.0 millimeter device. So that agrees and that's nice when that happens. So at this point, I measure my distal reference, I say I want a 30 whatever length, non compliant balloon to pre dilate. And then I do the rest of the measurements while the circulator goes and gets that first device. Here. You can calculate the length of the lesion overall. This is about 56 millimeters of stenosis longer than any stent that we have available on the market. So the strategy here is two stents to try to cover that lesion. We look throughout at the amount of calcium and fibrotic tissue as well to decide whether or not we need to do plaque modification. We'll talk about those criteria. And then I want to look at my proximal reference. Find an area again with less than 50% pla burden. Calculate the average vessel diameter, the average lumen diameter and then decide what post dilation balloon I want to use. Proximately. I'm gonna be 30 distally. But if I get to the proximal led, hopefully I'm not in a 30 vessel for most people, that's 35 or larger. So similarly, the vessel diameter is 44 downsized to the nearest size is a 4.0 millimeter balloon. The lumen diameter is 33 and we would upsize that to a 35 by and large. I would posit that if you're using ibis or OCT to guide the size of your devices, be conservative, take the smaller of the two, we're gonna go back an image afterwards. You can always go back in with a larger balloon at higher pressure. If you oversize from the very beginning, Papyrus covered, stents are very expensive and not quite so fun to put in and perfusion balloons are back as of a month ago. So, uh again, hopefully not something we're needing to use that frequently. So what was done in the study was a 3029 millimeter seol misal stent in the mid portion of 3533 proximately a little bit of an overlap. You take the angiogram, it looks good, but that's not where you stop because you wanna repeat your imaging and make sure you hit those criteria. So looking at the distal edge of this stent, the pla burden was 19.6% less than the 50% that we had talked about. And now we're going to talk about areas instead of diameters. So the lumen is 6.05 square millimeters in the healthy segment just distal to the stent jumping to the proximal edge, there's a 27% plaque burden, that's less than 50% we've achieved that we can trust the authors, hopefully that there's no edge dissection. And then as we're scrolling through some technologies use A I to do this, others require you to use your eyes to do this. The minimal stent area was found to be 5.2 square millimeters. So not quite 90% of the distal reference lumen which would be 5.4 square millimeters, but definitely over the five square millimeters that was defined as success. Uh In this study, I would also say, and we can talk about the data behind it. Please don't leave left, mains, proximal led s proximal circumflex at five square millimeters. Those vessels do need to be larger after PC I. But this was given as an example from the ultimate study as to what, what an ideal PC I would look like. And we'll talk about some more real world examples here in just a bit. All right. So two year follow up published in 2020 from the ultimate trial showed that there still is a statistically significant reduction in target vessel failure, driven primarily by target lesion failure overall. And again, we can see that there are trends towards less stent thrombosis and clinical TLR, meaning the patients had to come in early because something went wrong with the stent that they went uh that they had as well, but overall small numbers. So one stent thrombosis in the IVIS guided group seven in the angiographic guiding group, out of 700 patients, stents have gotten better and stent thrombosis is something that knock on wood. We're hopefully not seeing that often as given that I'm on call tonight. All right. Uh hopefully, no flight delays. So the three year follow up. So this is where uh this was presented at TCT during COVID. And this is where now we can talk about. This is the most recent evidence we have uh for this patient population and all come our patient population as predicted or as we saw before, there is a 40% reduction in target vessel failure, again driven by target lesion failure. But now what we can say for patients who get Ibis guided PC I based on this study is that there is a statistically significant reduction in stent thrombosis and 88% less chance of having your stents clawed off if you use intravascular imaging guidance Ibis guidance in this study versus angiographic guidance. Again, this is the most recent follow up, published five and 10 year follow ups are planned from what I know. Um there is still a trend toward less target lesion revascularization as well. So where we stopped the story at the last presentation was here at 12 months. And what you can see over the course of three years is that those curves continue to separate So now at the end of three years, if I do Ibis guided PC I, the chance of a bad thing happening to that patient is just about 7%. It's 10.7% if you don't use Ibis. And on this chart to the right, the dotted line is if I did optimal PC I, if I hit all three of those criteria at the end of three years, the chances of target vessel failure are just over 4% if I use IVIS. But I didn't optimize potentially because I didn't recognize there was calcium, I didn't do my IVIS beforehand and I picked the wrong stent. The chance of bad things happening to that patient is almost the same as if you didn't use Ibis at all. So the use of intravascular imaging is important, but also using it to plan the procedure and optimize the procedure improves outcomes for patients. This is called a landmark analysis. So we take the patients that are in the 1st 12 months and throw them out if something bad happened to them. And then we wanna see if over time, if there's an ongoing benefit or if it really is just from that beginning or that first year. And what was found is that after you take the bad things out from the 1st 12 months, ongoing patients with Ibis got to PC I numerically did better. This was not statistically significant but there wasn't overall separation. So to be determined whether or not at five years and 10 years if that remains statistically significant. So presented slightly differently year over year. So this is angiographic guidance in orange, one of my least favorite colors in the world is a Van fan and in blue is IVIS Guidance, which seems to be a Centa color. So we'll we'll preference that one today year over year and group over group there is a benefit to IVIS guidance over angiographic guided PC I throughout that is statistically significant. Similarly, the penalty for suboptimal PC I continues to accrue over time and optimal PC I uh is better. So this is an algorithm from the improved trial, which is an ongoing randomized control trial run out of medstar randomizing patients to Ibis guided PC I versus Angiographic guided PC I um specifically using Medronic stents in Phillips IVIS. And so this is the algorithm that now we use in order to determine whether or not we're doing a good job and how to do Ibis guided PC. I um I talked to Amy this morning. These slides will be available to anybody who wants them. I'm happy to share notes, et cetera on this and in sources as well, but it's what we talked about. So, putting the intravascular imaging down before doing stenting, measuring the vessel distally, taking the vessel and sizing down or the lumen and sizing up and making that our device size coming to the proximal vessel to determining what post dilation balloon we want to use at the proximal vessel, calculating the length when you have access to that, either on co registration or with mechanical ius. And I'll show some examples of both of those. And then doing your procedure post dilating with a non compliant routinely and then repeat your imaging to make sure that you're fully expanded. Once you hit these criteria, you're done and the PC I is over, if you don't hit these criteria, then you have to modify the stent until you achieve those criteria. And the goal of that trial is to determine whether or not intravascular ultrasound matters in an American cohort. As you saw before, the ultimate trial was Chinese. We'll talk about IVSXPL in just a moment, which is a Korean trial. We don't have any great American data for the use of Ibis and whether or not it truly matters, which is probably a hold up for the guidelines in the United States. So uh a case example, an unfortunate gentleman who presented to outside hospital, one with an anterior sty uh as led was occluded, they wired it, but they weren't able to cross with anything. This led was very heavily calcified and they didn't have access to calcium modification at that hospital. So they transfer him to outside hospital two, which is a partner of ours, um a non surgical center and they were able to bring the patient to the Cath lab. Cross it with a wire, but they weren't able to get balloons or they're more limited calcium modification tools to cross by the time he got to Saint Thomas, unfortunately, he was 40 hours into his infarct. Now, chest pain free. Uh on echocardiogram had an ejection fraction in the high twenties. Uh Our surgeons looked at him, got an MRI because they still believe in viability. His anterior wall was uh edema and scar. Uh So the decision was made to not revascularize the L ad the patient was asymptomatic. But we know from a trial called complete that if you fix anything else, if a patient comes in with a semi, that's over 70% the patient lives longer. So the patient was referred for PC I of this obtuse marginal as well uh in the setting of a complete revascularization. So again, when we're doing this, we want to go in before we put in stents. Sometimes you have to use a two or 2.5 millimeter balloon to pre dilate before the IVIS catheter will cross. We want to go distal to the lesion, find a spot with less than 50% plaque, come to the proximal edge and try to find our landing zone. And then in between decide whether or not we need to do any kind of plaque modification. So this is called co registration. The white line is where the Ibis image is with a 20 megahertz solid state IVIS on the pull back and we're able to do that and not just have to look at the two D image and mentally figure out where in the vessel we are, but that allows us to lay that over the angiogram. So in this example, my distal reference vessel is 3.15 millimeters by the vessel. So unfortunately, we have to calculate this in our mind. What are these averages two o'clock in the morning in a semi always uh fun to do mental math. Uh Siri thankfully can hear me from across the room. Hopefully, she didn't turn on just now. Uh The vessel itself is 2.8 millimeters. So vessel size up 28 becomes a 30 or sorry lumen size up the vessel size down 315, come down becomes a 30 and I'm at 24% black burden. So I've called for my three millimeter non compliant balloon while I do the balance of my measurements at the proximal edge of that obtuse marginal. There's a cuff of healthy tissue with 23% plaque. The vessel is 3.9 millimeters average. The lumen is 335, so 335 sizes up to a 3539 downsizes to a 35 or 375. So I know that I'm going to go in and post dilate with a 3.5 millimeter non compliant balloon at the proximal portion of the stent and because I use co registration. I know that my distance is about 22 millimeters. So I wanna pre dilate with the 30, I'm gonna use a 3023 stent. I'm gonna go back and post dilate with a 30 at 18 atmospheres distally, a 35 millimeter balloon proximately and then confirm my work so I can take an angiogram say it looks good and walk away. But that's not the best practice at this point because I want my patient in that group of optimal PC I because I don't want them to come back to the Cath lab at any point in the near or distant future. So we do our procedure, we go back in, we do our pull back. And what's nice about this too is with the use of intravascular imaging. You can tell if there's a dissection or a perforation, not as much a perforation, excuse me, but a dissection and you've got good side branch flow. So this is my final shot with the wires back that I can then core. And what I can see is that my stent edge is in an area with less than 50% Blackbird and distally as I get to the proximal stent edge, it's also in an area with less than 50% Blackbird. And we do measure that and report it. And then most importantly, our minimal stent area 6.1 square millimeters. So over five square millimeters And if you recall our distal reference area was 6.0. So well. So it hits both of those criteria. It's over 90%. It's over five square millimeters. Patient goes home the next day. This was done a couple of years ago. His ejection fraction has improved to the high thirties. He doesn't need an I CD. He's on optimal medical therapy and has been asymptomatic from a cardiovascular standpoint since then. And all that's left is a wire out shot to make sure that there is no perforation as well. So another trial uh again, I mentioned there was gonna be AAA Korean trial. Uh that also is mentioned in the guidelines. So Ibis XPL was a trial of 1400 patients who were getting durable polymer everolimus eluding stents over 28 millimeters in length. So they defined that as a long lesion, half of the patients got IVIS guided PC I, half of the patients got angiographic, guided PC I. And what was found is at the end of five years, there was a 50% reduction in macerates, bad things happening to patients with long stents. If you use IVIS Guidance, a 46% reduction in target lesion revascularization. So nearly 50% less likely to need to come back to have a stent retouched up or redone uh from that standpoint, just like we saw with ultimate and these other trials, the curves separate early, they stay separated throughout the course of five years. Uh So the benefit is there across the entire follow up period. Numerically, you can see that there is a statistically significant reduction in Mace and TLR out of 700 patients. The event rates were in the in the thirties to fifties. Um So thankfully, stents are good, but Ibis makes our good stents even better that landmark analysis done as well. So the question was if patients got through the first year, OK. Was there an ongoing benefit? Interestingly what was found is over the course of four years. Follow up, there was a significant reduction in the chance of bad things happening to those patients. So not only did it matter to do it at the index procedure for the first year but for the subsequent five years, which if it's my mother or grandmother, I care about the next five and 50 years uh on how they're going to do and hopefully not have to come back to the Cath lab and looking at optimization versus non optimized PC I at one year, just the same criteria that we talked about in ultimate for patients that got optimal PC I. In this study, there was a 69% reduction in the chance of bad things happening, that benefit or penalty is paid in the first year for the subsequent four years. Whether or not you did a good job doesn't matter as much, but it definitely matters uh in that first year. So we wanna do a good job as often as possible. All right. So another case, this is, um I guess we have a lot of included led s that are non viable. But uh a patient who came in uh with a non sty ejection fraction of 11% on MRI 5 to 10% on the echocardiogram was found to have an occluded L ad uh anomalous circumflex, as you can see here uh in the led territory was full thickness scar non viable. Um So probably culprit on the right or the circumflex hard to know. Uh after a heart team discussion, our Cath conference is at 6 a.m. on Wednesdays. So tomorrow morning, we'll talk about patients like this. She was deemed not a surgical candidate because of the lack of L ad viability and was referred for PC I. Um unfortunately not a protect for patient for the intervention list because she lives 200 miles away and didn't want to follow up with us. But uh recommendation was mechanical circulatory support because if we knocked off her right Maine, uh she doesn't have an L ad that would not be uh a good into a Thursday a couple of weeks ago. So we go in, we uh plan to do PC I of the right Coronary and the circumflex, I'll show the right coronary and the S or for the sake of brevity. Uh And then this is a uh mechanical IVIS. So the first example you saw was solid state IVIS. One of the downsides to mechanical Ibis with automatic pull back is that you can get air in there. So that's why during half of the run, you can't see much of anything. There's air bubbles inside the catheter there. But it still allows us to calculate the distal reference, the proximal reference and the benefit of mechanical IVIS depend all vendors do. This is that you can calculate length as well. So this is an eight millimeter a second pull back. So it knows how long does it take to get from point A to point B? And on the console, you can calculate the length. Uh core administration only currently available with OCT which is light based. Uh and then with the 20 megahertz solid state Ibis as well. So none of the others have the co registration. So what we found is that the distal vessel was 3.2 millimeters in that right Coronary, the right main was about four millimeters just distal to that bifurcation was 3.7. So I picked a three millimeter device with a plan to post is 835 proximately very similar to the obtuse marginal I showed you earlier. So we proceed with that intervention and then this is the post run. So uh better job clearing the air out of the catheter this time. And again, what we're looking for is the proximal edge, the distal edge less than 50% black burden the minimal stent area. And is there any edge dissection? The mechanical IVIS does not give you the ability to do Doppler inside the blood vessel. The 20 megahertz solid say IVIS allows you to do power Doppler inside the blood vessel, which also is look for dissections as well that might be angiographically or ultrasound, not evident. So here you can see the minimal stent area which is auto calculated with this vendor was 5.67 square millimeters. Well over the five square millimeters that we would shoot for. In a study, the distal reference vessel had 24% plaque burden and the lumen area was 576. So my 567 was well over 90% of that distal reference and the proximal reference was 26% plaque burden. So we use that information to decide how to treat the patient and then to make sure that we've done an optimal job afterwards. All that's left on that was the wire back shot and then turned our attention to the circumflex, which was also a relatively straightforward procedure. All right. So speaking of complex P CIA little bit more recent data. So in 2023 renovate Complex PC I, uh actually, this is a Lumia four, I apologize, didn't update the title. So uh ignore the title there. This is a lion which is a trial of OCT versus IVIS. So we have a lot of data saying that the use of intravascular ultrasound improves outcomes for patients. And the question was, does OCT which is light based improve outcomes for patients? And how does it compare to patients who are getting IVIS guided PC I? So these were lesions that were less than 40 millimeters in 225 to 35 vessels and they excluded the complex lesions. This was more of a simple patient trial. So patients who had left mains osteo disease, F graft CTO S bifurcations and intent were all excluded. And what was found overall is that IVIS and OCT are equivalent in the alum three trial. Again, a relatively small study, uh 100 and 40 patients in each arm as well. What was found? And I think we talked about that just a little bit ago is that you were significantly more likely to find a dissection using OCT. But the clinical relevance of those small dissections remains to be determined. Again, not an outcomes trial. This was just a trial to see if you could see the same thing with OCT and with ibis. All right. This one really is renovate complex PC I I apologize. So 1600 patients who are randomized, 2 to 1 to imaging guidance versus angiographic guidance who undergoing complex PC I. And here are the definitions of complex PC I in this trial. And what was found at three year follow up is that patients who got complex PC I with IVIS Guidance were significantly better with regards to target vessel failure with an overall 46% relative risk reduction. But what was also interesting and statistically significant was that patients getting complex PC I with Ibis or imaging guidance were 53% less likely to die at the end of three years. Again, talking to patients about the benefit of these procedures that we're doing outside of left main PC I for stable ischemic heart disease, we're not improving mortality. And if we do a bad job with complex elective PC I, we may be causing harm from that standpoint, looking at the subgroups and again, this is tiny, I promise the slides will be shared. You can see that uh imaging guidance ibis and oct improved outcomes. The majority of the benefit was derived for patients who had chronic total occlusion, left main disease, long lesions and osteo stenosis. In the study. Small numbers not um you know, hypothesis generating, there was more of a benefit for female patients, diabetics, patients with chronic kidney disease and patients with uh preserved ejection fraction. Again, hypothesis generating for the subgroups. But based on this data in a randomized controlled well done trial. The hypothesis is that the use of intravascular imaging saves lives. So back to that case, that we talked about a little bit ago, this was a gentleman in his late forties who's a truck driver. And in Tennessee, you have to have an ejection fraction over 40% in order to drive a truck. Uh he was found to have a drop in his ejection fraction. He had had prior bypass with a Lima to the L AD A van graft to the circumflex and a non dominant, right Coronary. Uh Unfortunately, he lost his vein graft to the circumflex. So, uh came for PC I after repeat surgery was thought not to be worth it for a patient with uh Peyton Lima to the L AD. So proceeded with PC I. Uh So this is not a CTO talk crossed with a a jacketed uh hydrophilic taper guidewire able to get down pre dilate a little bit. And then generally speaking, after crossing, we don't want to take angiograms, but we couldn't see anything after that lake in the proximal vessel. So after ensuring on the first run of IVIS that there was no dissection did an angiogram and this is what we see, you can see angiographically that there's heavy calcium in the mid vessel at a bifurcation point. This is a chronic total occlusion. So my question is, what size stent do I need? Do I need to do plaque modification, etcetera. So another example uh of a mechanical ibis pullback uh from a different vendor, I'll try to speed it up in the interest of time. But what we can see is better if I do it over here. So as we're pulling back, you have calcium, which is bright white with shadow. You have soft plaque, which is light gray, you have some fibrotic tissue which is white without shadow. I'm measuring my reference distally. It's always hard to focus right on the same spot. But anyway, I'll keep going. And as we pull back towards the proximal circumflex, just a diffusely calcified vessel. As we get back into the left main artery, there is some soft plaque, a little bit of a dissection flap there. But overall, this allows us to get the information, we need to decide how to treat this patient. So how do we use ibis to decide whether or not plaque modification, calcium modification is necessary. If we're using OCT, we have the rule of fives if it's more than five millimeters long, if it's more than 0.5 millimeters deep because OCT can see the depth of calcium because it's a crystal structure. And if it's more than 50% of the vessel 100 80 degrees, those are the, when we recommend calcium or plaque modification, Ibis can't see through calcium because it's sound based and sound bounces off of hard objects. So what was found in an analysis from CRF, Akiko Mahara and others published this is, they looked back and said, what factors on the ibis predict under expansion of the stent? We wanna make sure we're modifying the plaque before we put the stent in. Once you have the stent in and it's dog bone, it becomes a lot more difficult to save that stent and we're really limited to lithotripsy opn and laser at that point. And what was found is that if you had two or more of these factors, the patients were more likely than not to have under expansion of the stent where plaque modification would then be recommended. So those factors are, do you have a long lesion? More than five millimeters in length with 270 degrees of calcium? Is there any spot that is circumferential? 360 degree calcium? Is there any spot with a nodule which are always terrible? And is there any small vessel? So less than 3.5 millimeters again, two or more of these predicted bad stent expansion for calcium modification would then potentially be recommended. So this gentleman had a long area of calcification, had several spots of 360 had a calcified nodule. So ended up and again, this is not a PC I talk. This is an IVIS talk, ended up doing lithotripsy. Uh Once we've gone through and balloon a vessel, you're more limited in what calcium modification you can do. Rotational arrect toy is safe at that point. But there was a large loom and I didn't think rotational would be quite as beneficial. So ended up doing Lithotripsy after high pressure and sea ballooning was not adequate. And then we want to go back in after we do our PC I and repeat our intravascular imaging turn off the laser pointer and again, in the interest of time, I'll run through a little bit more quickly. So, what we're looking for again is that our edges are in less than 50% black burden that we have an area that is adequate on the way back. And that our proximal edge also is in an area with less than 50% black burden and that there is no edge dissection. So this is a 45 megahertz uh mechanical catheter. So after making sure that we've achieved those criteria, all that's left is for the wire outshot to make sure there's not a complication or perforation. We left all of that small vessel disease distally alone. His ejection fraction did improve to the mid forties. Uh He is now back to driving a truck um on GDMT, of course, for his heart failure as well. All right, a couple more recent trials, a network meta analysis and then an exciting guideline update. So Lumia four was published uh last year was a randomized study that randomized patients to oct guidance versus angiographic guidance. 18 countries, 2500 patients. This was supposed to be one of the pivotal trials to say that intravascular imaging matters. Unfortunately, this started just before COVID and then went on during COVID. So there was a lot of issue with patient follow up and getting patients enrolled. And what was found overall is that patients in the group of uh that got OCT guided PC I. The primary outcome, target vessel failure. There was no statistically significant reduction in the rates of target vessel failure. With OCT guided patients at 24 months. It was numerically better but it was not statistically significant looking though at subgroup analysis. What was seen in alum four is that patients who got IOCT guided PC I did have larger stent diameters and were significantly less likely to have stent thrombosis. These were not the primary outcome, just hypothesis generating potentially a longer term outcome or follow up. We may see that that uh drives uh differences in benefits. But as it stands right now, Lumia four did not show a significant reduction in target vessel failure. With OCT. October was a similar trial to a Lian four that randomized patients to OCT guidance versus angiographic guidance. But this included only bifurcation lesions. And what was found in looking at 1200 patients who were randomized 1 to 1, I guess they snuck in an extra one in the angiographic guided side was that OCT guided PC I reduced the chance of bad things happening to 30% by to the patient by 30% a 30% relative risk reduction which was statistically significant. Um So again, based on this, with bifurcations, OCT showed that there was improvement in target vessel failure and overall mace rates as well. So this was published at ESC last year. So about a year ago, now taking all of these studies that we've talked about. I tried to hit on all the ones that were more than 10% of this meta analysis. Uh And then finally published in lancet earlier this year, a meta analysis showed that the use of intravascular ultrasound across the board or intravascular imaging reduced the rates of target lesion failure by 29% Ibis and OCT were equivalent, but both were independently better than angiographic guided PC I. So this is IVIS versus angiogram, OCT versus angiogram using something doesn't matter what you use versus angiogram. And then OCT and IVIS were equivalent in all of the studies as far as preventing target lesion failure. What was also seen is that overall, there is a 53% reduction in cardiac death, ibis and OCT were equivalent. But taking all of the studies into account, we can now save lives with use of intravascular imaging. Looking at other end points, there was a 25% reduction in all cause death if we use intravascular imaging, an 18% reduction in target vessel myocardial infarction. A 28% reduction in target lesion revascularization and a 48% reduction in stent thrombosis. Overall. Again, the use of intravascular imaging is better for our patients than doing it by just looking at the angiogram. So based upon these data and these recommendations, the guidelines that uh were updated two weeks ago at ESC now give a class one, a recommendation meaning you have to do imaging unless there's a very good reason not to when you're doing complex intervention, left mains bifurcations and long lesions. Because of the studies that show that there is a mortality benefit for patients there. The balance of the European guidelines are from 2018 where like in the United States, the rest of the imaging guidelines are a two way recommendation, do it if you want to, but you don't have to. We're not going to track your outcomes or set reimbursement based upon the use of intravascular imaging, looking at other American guidelines or set ups the sky. Uh Consensus document sky is the organization that tells us interventional cardiology what to do. Uh Probably the best organization is an interventional cardiologist sky determines that intravascular imaging is definitely beneficial to determine whether or not you did a good job putting in the stent and to figure out the size, it's probably useful to determine whether or not left mains are significant based on data from Minnesota. If the minimal Luminal area is less than six square millimeters in the left main, that's equivalent to an abnormal FFR. So you can make your decisions whether or not you treat based on that. There's some Korean data. If you guys have a large Korean population, we don't in middle Tennessee, uh that 5.4 might be a better number for them. You can use it to assess plaque morphology, decide whether or not. Something is calcium fibrotic soft, whether you're not, you need to do predilatation plaque modification or if potentially direct sting might be better in the setting of thrombus. And then we shouldn't be using ibis outside of the left main to decide whether or not to treat something based on the currently available data. So use physiology outside of the left main ifrrfrffr insert your favorite r here, but then the left main, you can use IVIS to decide how to treat. And again, our guidelines have not been updated to take into account the most recent data set. So the United States remains a class two, a recommendation. With the exception of a class three, don't put ibis in people for fun if you're not planning to do something with that information. Um Also you guys are a transplant center as well. So our patients will come back at one month and 12 months to do IVIS to look for signs of early rejection, cardiac allograph vasculopathy. Because if that internal wall thickness uh is starting to increase, we can change their immunosuppression so that we can prevent them from rejecting that heart as well. So uh another more niche use for our centers that are doing transplant. So why don't people use intravascular ultrasound? This is from poll, it takes too long, it costs too much. It's dangerous. I've heard that it's hard to interpret and it won't change my management. Hopefully, over the last 55 minutes. We've talked about studies that say it will change your management and it does matter to the patient. It takes too long with the use of artificial intelligence, with the use of programs and pathways to make this part of routine utilization. I would say that it probably only adds about 30 seconds to a minute to the case to do each run and we should just do it at the beginning at the end. Too expensive. I think that the cost to the patient uh is zero. The cost of the hospital is relatively minimal. But when that patient comes back in at two o'clock in the morning with an M I uh four weeks later, there are definite downsides financially to that. So looking at rates, this is provided by Phillips, which is interesting because they have the X ray machines, they have the imaging systems and they're able to calculate what percentage of PC I truly is being done with imaging guidance across the world in Japan. It's nearly 100% in the United States and North America, we're better than we used to be. It's still less than 30%. But again, it's not a class one guideline. So speaking of class one guidelines, uh a class one, a recommendation is the use of radial artery for PC I. Um So taking rifle and rival in other studies, the guideline writers for the revascularization guidelines say again, class one do this unless there's a reason. Absolute reason not to. We should be using the radial artery for PC I for all of our patients unless you're going eight French or mechanical circulatory support, both for the acute Coronary syndrome patient and the stable ischemic heart disease. The patient who comes in from home through holding and what we've seen in the meta analysis that led to that radial versus femoral is that there's a 26% reduction in mortality for the patients. If you go radial, as we just talked about, there's a 25% reduction in mortality if we use intravascular imaging. So to the guideline writers who are out there, I would posit why if we're gonna give this a class one recommendation? Why has there not been an update to the guidelines to say at least limited use of intravascular imaging, saves lives and we should be using that on a daily basis. So I guess in summary, in conclusion, um I personally am at about 96% imaging guidance for PC I. In my data from last year, there were a few cases where it wouldn't cross before or after and I didn't want accordion the stent, I would hope and posit that after the preponderance of the data is out there, it is relatively straightforward. It's easy enough to interpret, especially with the use of artificial intelligence, more of that will come with, with more vendors and I think it does matter and does save lives. So if my mother or grandmother or myself on your table at some point, given my family history, uh I would hope that you'd go radio and use Ibis. Um My contact information again, uh Tenny Virginia Tech fans uh on the line, I apologize. Uh These are my kids uh smiling at a Vanderbilt game which is relatively rare. So thank you again for the opportunity d for the invitation uh to come hang out. Published September 19, 2024 Created by
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