Hi, everyone. Good morning. You're in the Cath PCI session on advanced imaging. My name is Connie Anderson, or Cornelia, as you see over there. Okay, so I'm not one for introductions. I usually just turn it right over, but I did want to take a moment to introduce our speaker, Dr. David Kanzari. He is an interventional cardiologist and an avid research contributor in the field. I've had the privilege to work with him for many years. He served on the Cath PCI Registry Steering Committee from 2016 to 2022. One of his contributions during that time was spearheading the development of two metrics, which report technical and procedural success for chronic total occlusion PCI. These metrics were unanimously approved by the committee and, as most of you know, have been part of the Executive Summary Metric Portfolio since 2021 Q3. In 2023, Dr. Kanzari came back to the Cath PCI Registry Steering Committee as the chair-elect and, as of April, is now the chair. Dr. Kanzari's calm and thoughtful disposition, coupled with his expansive knowledge of all things cardiology and his comprehensive understanding of the purpose of the Registry and the NCDR have transformed steering committee discussions. As you can see, despite his very full schedule and many obligations, Dr. Kanzari has prioritized being here with all of you at the ACC's Quality Summit. Now, before I turn it over to him, come stand up here, I have a question for you. Yes. Do you know what I'm going to ask you? No, but I'm going to ask you for a letter of recommendation. Okay. And are you nervous? No. Oh, okay. I should be. Okay. Okay. So, this is just one question. On a scale from- Oh, for the question. Yes, I am nervous. Yes, I agree. Okay, okay. On a scale from zero to 10, if 10 is the most possible and zero is not at all, how much of a cardiology nerd are you? 10 is the most possible? I'm an 11, I think. Yeah. Yeah. Okay. Well, on that note, I'll turn it over to you. Okay. Thank you. I have a few more things too, if it matters. Well, thank you, Connie. And Connie really is my partner in all of these endeavors for the CATH PCI program. Again, I'm David Kinzeri from Atlanta, Georgia. It's a very welcomed opportunity for me to be with you. I'm privileged to be with you and with such attendance. This is my first attendance at the ACC Equality Summit, and I hope certainly not my last. I know that it's only my second visit to San Antonio, and for those of you who are going to explore the history of this community and city, I will also add just something off the side, and that is that there is Dave Little's boots and Paris Hatters. So if you need a custom pair of cowboy boots and a custom cowboy hat, those are the places to go as well. Well, in our transition then from that introduction though to the CATH PCI registry and where we're heading with intravascular imaging, again, it's a welcomed opportunity to share with you evolving perspectives with the application of imaging and how it's being folded into our data collection for CATH PCI. And specifically, we want to share with you the purpose of imaging, the evolving evolution of evidence supporting this, and help understand or inform how this is going to influence practice in changing standards of care. And specifically, our objectives is to share with you the types of imaging modalities used for coronary artery disease assessment, for ischemic assessment, both non-invasive and invasive modalities. Secondly, to identify at least two ways that advanced imaging is changing the cardiovascular care landscape, and there are, in fact, multiple such examples. And third, to recognize how CATH PCI registry is collecting the performance of intravascular imaging during the PCI procedure itself. For some time, historically, CATH PCI has collected information on non-invasive functional assessments for coronary artery disease, and expectedly so, as an indication to serve as the appropriateness for the performance of cardiac catheterization and possibly percutaneous revascularization. And historically, these methods have included standard treadmill stress testing to exercise or pharmacologic-based imaging assessments with nuclear or SPECT imaging and stress echocardiography, but also the evolution of more novel modalities of non-invasive assessments of ischemic heart disease, including cardiac MRI and, of course, CT imaging, not simply with a coronary calcium score, but with non-invasive coronary CT angiography. And this latter aspect, this latter modality, as I'll soon share with you, is becoming increasingly commonplace across hospitals in the United States, and certainly very much so abroad. To highlight, in part, the limitations, however, of non-invasive imaging for coronary artery disease assessment, we nilk no further than the more contemporary ischemia trial. And in this study, 8,518 patients were identified as potential enrollees with moderate or severe ischemia by non-invasive stress testing. And per protocol in this study, nearly 6,000 of these individuals underwent coronary CT angiography. But notably, even despite having a high-risk stress test, still roughly one quarter of these individuals had no significant obstructive coronary disease when CT angiography was performed. So highlighting, again, the limitations of non-invasive stress testing. Moreover, among the individuals who did have obstructive coronary artery disease, nearly 3,000 of these enrolled patients with moderate to severe ischemia. Still, when they underwent cardiac catheterization, the prevalence of disease distribution was fairly evenly divided among those individuals having single-vessel disease or multi-vessel disease. So even high-risk stress tests cannot necessarily predict accurately the coronary artery disease burden. CT angiography, as I've implied, is becoming increasingly commonplace in the United States and certainly has been a standard for assessment of coronary artery disease in many other geographies, particularly in Europe and in Asia. And in this instance, coronary CT angiography identifies significant disease in the right coronary artery as well as in the left anterior descending artery. And this is confirmed with invasive coronary angiography diagnostic cardiac catheterization to be sure identifying a significant lesion in the right coronary artery, but perhaps more angiographically moderate disease in the left anterior descending artery. And now coronary CT angiography not only can provide insight to the anatomic disease distribution and or severity, but also the functional assessment by applying fluid flow dynamics, a technology very similar to what might be applied to designing an airplane or a Formula 1 race car, for instance. The same technology can be applied to the coronary CT angiogram in which we can assess the disease physiologic significance by what is termed CTFFR. And with a value of less than 0.8, similar to fractional flow reserve performed routinely in cardiac catheterization laboratories, in this particular instance, CTFFR identifies significant disease both in the right coronary artery as well as in the left anterior descending artery. And despite the more moderate appearance angiographically of the left anterior descending artery, when invasive FFR is performed, it too is functionally significant. And a fairly high correlation between the noninvasive CTFFR assessment and invasive cardiac catheterization. And altogether, then, this informs the operator to successfully treat both the right coronary artery and the left anterior descending artery disease. There is a marked rise in the performance of coronary CT angiography, but also cardiac MRI in the United States. These data are a bit dated because of the collection methods in the United States for determining this, but there is, even back at 2019, there is a progressive rise in the performance of coronary CT angiography, a progressive rise in PET imaging as well, but also cardiac MRI, and a progressive decline in the performance of myocardial perfusion imaging, that is, historical standard nuclear stress testing. Stress ductal cardiography is also moderately declining as well. And in part it's because of the high radiation burden associated with myocardial perfusion imaging studies. But moreover, these numbers have more dramatically changed in the past five years, at least anecdotally, in part because of guideline endorsement for the performance of coronary CT angiography, but also because of improving reimbursement for the performance of these procedures in the United States. And so perhaps a better example of such is in geographies such as the United Kingdom, as shown here, in which coronary CT angiography has been long approved. In fact, there are some smaller hospitals which have closed their cardiac cath labs and removed that equipment and supplanted it with CT imaging technology as a replacement for cardiac catheterization. And in this geography, where like in the United States now, coronary CT angiography has a class one recommendation for non-invasive assessment by guidelines, there is an exponential rise in the performance of coronary CT angiography over the same time period, a continued escalation in cardiac MRI as well, and correspondingly a decline in the performance of non-invasive nuclear stress testing. Now one might ask, well, what's happening then to the cardiac catheterization labs? Are these CT angiograms replacing the performance of invasive angiography, or are they increasing the performance of angiography? And the answer is a bit mixed, because yes, in many instances, coronary CT angiography, if the study is normal, has a very high negative predictive value, meaning that there's a very high correlation that the anatomy is going to be normal. But when there is disease that's observed, this oftentimes does lead to the performance of invasive angiography as a confirmatory measure. And so there's somewhat of a balancing effect. And then shown in the lower right-hand panel is the prevalence of invasive coronary angiography over this time period in the United Kingdom, showing that it's really neither going up nor going down with the increasing performance of CT angiography for these reasons. In addition to CT angiography now as a non-invasive modality demonstrating not only the disease burden and the anatomy, but also functional significance, now CT angiography also may have the potential to demonstrate plaque characterization, that is, identify not simply calcified versus fibrous plaque, but also plaque characteristics such as lipid-rich necrotic cores and high-risk lesions that might portend a higher likelihood of an acute coronary syndrome. And one such example is the REVEAL plaque study in which patients with coronary artery disease underwent the gold standard, which we'll soon discuss, invasive intravascular ultrasound, and compared that to the characteristics identified by the performance of CT angiography. And in fact, there was a very high correlation or agreement between the two modalities in identifying characteristics of the plaque that may influence clinical decision-making, not simply with regard to the performance of a cath or an intervention, but perhaps patients with high plaque burden or lipid or very soft plaque that is associated with higher risk for adverse events might influence how we more aggressively treat these patients with medical therapy and or perform surveillance for them. So with that background, we transition then to the performance of invasive angiography in the cath lab itself, which is, of course, the focus as well for a cath PCI. The background to this, as many of you experience working in your hospitals, is that PCI has evolved to the treatment of much more complex anatomies that we didn't envision even 20 years prior. Our patients are becoming more complex, and the surgical turndown patients being, as an example, far more commonplace, and the indications for performing these procedures are more varied as well. There has been, as of implied, considerable development and achievement in not only physiology with FFR assessments, as we'll soon discuss, but imaging assessments combined with physiology at all phases or all components of the interventional procedure, that is, before the intervention, during the intervention, and after the intervention. No standardized definitions for many of these metrics, however, exist, and to that end, we've now held an academic research consortium, or you've heard of the AHRQ documents, and we've now had two imaging consortium meetings to define clinical standards for intravascular imaging, not simply for clinical trials, but for clinical practice as well. And this is particularly relevant for at least two reasons. One is that there's increasing inclusion of the use of intravascular imaging, not simply in clinical practice, but a mandate in clinical trials, and also there is recent escalating endorsement in societal guidelines for both physiology, but also imaging assessment in the performance of cardiac catheterization and intervention. And just as an example, at present, the more dated American College of Cardiology, American Heart Association guidelines afford a class 2A recommendation, so a very high level of recommendation to the use of intravascular imaging for percutaneous intervention. But just two weeks ago, at the European Society of Cardiology meeting, the European Society of Cardiology guidelines now have escalated to a 1A recommendation for the use of intravascular imaging for percutaneous coronary intervention. This is their highest level of endorsement, it is a class 1 recommendation, and it's a what's termed class 1A recommendation, because it's based on randomized clinical trials. And as I'll soon share with you, based on randomized trials that not only improve the procedure itself, but most importantly, improve the short and long-term outcome for our patients undergoing these procedures. As a broader perspective then, intravascular imaging, as I've shared, helps us, before the intervention, identify the plaque components. For instance, is this a very calcified plaque that might require arthrectomy or intravascular lithotripsy or some other treatment modality? It helps us assess the geographic disease distribution so that we make sure we don't miss disease. One particular study suggested that even after routine stent placement, by focusing on the angiogram alone, we miss up to a third of significant lesions if we then later measure them by imaging or physiology assessment. During the component of the procedure, intravascular imaging helps us size the balloons for length and diameter. It helps us size the appropriate stent placement as well. And it helps us ensure that there's adequate stent apposition and expansion in the vessel because, for example, incomplete stent expansion is the greatest predictor of instant restenosis, which is unfrequent, but most commonly is related to an underexpanded stent. Even though it may look good by the angiogram, it may be underexpanded when an intravascular imaging catheter is placed. It moreover helps us avoid post-procedure or immediate periprocedural complications, not only ensuring that the stent is well expanded, but it is also opposed to the vessel, malapposition being a high predictor of stent thrombosis, as well as avoiding edge dissections, which could result in abrupt vessel failure, and moreover ensuring that we've, as I've implied, adequately treated the entire geographic extent of the disease itself. So as an example, in this instance, using intravascular ultrasound, intravascular imaging informs the procedure not only prior to the intervention, during the treatment and preparation of the vessel, and following the stent placement as well. And this is such an example where, under the assessed category, this is a vessel with a roughly 180-degree arc of calcification from 12 o'clock to 7 o'clock. After predilating it with a balloon, you can appreciate the fractures now in the calcium, so ensuring adequate expansion of the vessel to permit stent delivery and placement, and then optimizing the procedure for full stent expansion to the appropriate vessel size. The three most common imaging modalities present today in clinical practice include intravascular ultrasound, intravascular ultrasound, optical coherence tomography, and near-infrared spectroscopy, which historically has been reserved more for research purposes, but now is being incorporated into some cardiac cath labs in the United States as well. And this is complemented by the non-invasive potential with CT angiography that I shared earlier. By far, among the imaging modalities, intravascular ultrasound remains the most commonly used technology. Optical coherence tomography is second to that, has greater fidelity or image resolution, but has some limitations with regard to requiring contrast injection and other limitations. And then near-infrared spectroscopy is now being combined oftentimes with intravascular ultrasound. And whereas IVUS and OCT perform similar information, provide similar information with regard to plaque volume and composition, with regard to the aspects of treatment that I shared with you earlier, near-infrared spectroscopy is helping identify plaque characteristics, such as a lipid-rich core that has been shown in previous clinical trials to predict the future occurrence of adverse events, such as myocardial infarction. Irrespective of IVUS or OCT utilization, the introduction or the application of intravascular imaging for percutaneous revascularization, as I've implied, most importantly, is associated with an improvement in the outcome, not only short-term, but over long-term follow-up for our patients. The use of intravascular imaging, again, by avoiding peri-procedural complications, by ensuring adequate stent apposition and appropriate disease coverage, those five minutes of the application of intravascular imaging translates into 10, 15 years, or longer, hopefully, of improvement and meaningful benefit to our patients undergoing intervention. And this has now been demonstrated in far more, shown here, of three contemporary large randomized international clinical trials highlighting that based on PCI performed with angiography visual assessment alone, again, the use of intravascular imaging is associated with significant and quite meaningful reductions in the occurrence of cardiovascular death, of myocardial infarction associated to the treated vessel, and the need for repeat revascularization. Indeed, presented just recently within the past year in network meta-analysis of over 13,000 patients included in sham-controlled randomized clinical trials, the use of intravascular imaging, whether OCT or IVUS, is associated with an approximate 30% reduction in this composite of what we term target vessel failure, that is, cardiovascular death, heart attacks, myocardial infarction, and the need for repeat revascularization. And that 30% reduction is driven by a nearly 50% reduction in cardiac death with the use of intravascular imaging. And that, in part, is largely driven by a nearly 20% reduction in myocardial infarction associated with the target vessel, and a nearly 30% reduction in the need for repeat revascularization, and moreover, a 50% reduction in the occurrence of stent thrombosis, again, by ensuring adequate stent apposition, avoiding edge dissections. Stent thrombosis, many of you will recall who have been in the space of interventional cardiology for years, has a high association with death and myocardial infarction. Okay, so we as interventional cardiologists would like to say that we as complex interventionists always know the evidence, and we always perform intravascular imaging, but the reality is somewhat disappointingly different. Specifically, as an example, in the Michigan Blue Cross Blue Shield registry of nearly 49,000 patients undergoing percutaneous revascularization, the use of intravascular imaging approaches only about 17%. And in separate analyses, when physicians are polled with regard to their use or their lack of use of intravascular imaging, it is oftentimes due to lack of awareness of the clinical benefit, lack of familiarity with the device technology, perhaps to the broadest extent, unfamiliarity with image interpretation. As I often say, these technologies do not work by intention to treat alone. That is, just putting the catheter down the artery doesn't suddenly translate to an improved outcome. The operator needs to, he or she needs to understand and interpret the image and act accordingly upon it. And at least for some instances, too, more at a perhaps hospital or administrative level, cost and reimbursement challenges, which are evolving, have been a barrier to the utilization of this quality measure. Recently, the American College of Cardiology Interventional Council published a consensus document, an expert consensus manuscript endorsing the use of intravascular imaging, and based on a wider and growing body of evidence basis supporting the clinical benefits of intravascular imaging, there were three conclusions, at least from this council meeting. Number one, that all cath labs should have imaging capabilities, whether it's OCT or IVUS was of lesser consequence. Intravascular imaging is essential as an adjunct to complex lesion subsets, very calcified lesions, unprotected left main lesions, long lesions, chronic total occlusions, and very importantly, education is essential to achieve the desired objectives. As an aside, intravascular imaging, too, in multiple manuscripts has also been demonstrated to be very cost effective. In the cost effectiveness terms, it is associated with an incremental cost effectiveness ratio that is considered not only cost effective, but of high value as well. And this is because of the benefits, the clinical benefits that can be realized with the use of imaging. To that end, many external parties, private insurers, recognize the value of intravascular imaging and therefore have associated it with a quality metric. As such an example, the Blue Cross Blue Shield Registry in Michigan recognizes and incentivizes hospitals as in many other states and with other insurers on the performance or the application of quality based metrics. And importantly, they recognize then the performance of PCI with the use of intravascular imaging as one such quality metric. To share with you as another example of my home institution, the Piedmont Healthcare System in Atlanta, Georgia, Piedmont now is 23 hospitals across the state of Georgia. It's the largest employer in the state of Georgia over Coca-Cola or Delta Airlines. And among our hospitals that have cardiac catheterization laboratories and PCI capabilities, recognizing the clinical benefits of intravascular imaging and the avoidance of complications, not so much from a value based external insurer perspective, but simply internally realizing the need for quality improvement, we raised the awareness across our programs of the benefits of intravascular imaging. And take as an example in January 2023, across these different hospitals with PCI capabilities, one institution, our main program in Atlanta where I work, utilized intravascular imaging more than 90% of all PCI procedures. But there were many other hospitals with a range of prevalence of the use of imaging from five to maybe at best 50%. And on average, this was 40% for the healthcare system that is now in just a little bit more than a year achieved roughly 75% prevalence or utilization across all PCI procedures. Again, based on the awareness and best practice sharing and networking with our colleagues as well. The field of intravascular imaging though also continues to rapidly evolve. Intravascular imaging as an example with optical coherence tomography with provision of even higher fidelity in the lower left hand panel can provide you information even with regard to the visualization and in part with AI applications, visualization of the stent struts. And you can even see in this lower left hand panel the example where a guide wire is exiting into a side branch through the stent struts themselves. There is not only the use of intravascular hemodynamic assessment now with fractional flow reserve too, but moreover there is now a term FFR angio, just to add to CTFFR and to FFR measures, there is angio FFR which is forthcoming, which is performing in real time the cardiac catheterization procedure, the diagnostic angiogram and technology that will then interpret the angiogram that you and I see on the screen and in a multi-vessel application immediately provide a hemodynamic assessment with FFR of the coronary angiogram tree of all three epicardial territories. There are also forthcoming technologies to further provide insight into plaque characterization as well. But perhaps the next nearest step for us with the use of intravascular imaging is combined intravascular imaging either with IVUS in the left hand panel or in the right hand panel with OCT, but applying artificial intelligence algorithms that also then can calculate an assessment of physiologic significance or FFR now with the imaging catheters as well. And this is now achievable with both intravascular ultrasound and with optical coherence technology. Both of these looking at considerations of the distribution of disease, the lesion length, the severity and providing the operator with a calculation of hemodynamic or physiologic significance not just with regard to the anatomic characterization. So putting it all together will be this concept of PCI navigation. And this is a very interesting concept in which we could perhaps identify the severity of disease anatomically, visually. We can identify the plaque characteristics. We can identify with intravascular imaging perhaps the physiologic significance. And then moreover, we can perform virtual PCI where we could say, well, if I just treat this proximal part of the left anterior descending artery and I don't, and I leave the rest of the disease more distally, what would be the hypothetical FFR or the physiologic benefit? And this will inform the procedure for operators in terms of how much is needed to treat and where. So having said all of that, historically the cath PCI registry has collected information on the use of intravascular imaging historically, as Connie would correct me otherwise, is that it was performed largely before the intervention itself. And we've evolved now in our ascertainment of this data to now collect the application of imaging both before, during or after the interventional component of the procedure. And we're not only collecting simply as a broad stroke whether intravascular imaging is performed, but the modality, whether it's intravascular ultrasound, optical coherence tomography, or near-infrared spectroscopy. And this is just one such example of an institution performing intravascular ultrasound in 60% of the cases, optical coherence tomography in nearly a third of the cases, and no performance of near-infrared spectroscopy. And in the right-hand panel, at least the average in the United States in the performance of imaging today still remains conditionally lower. It remains around 23% to 25% in the United States, and we would only expect this to continue to grow. However, it is importantly a marked improvement from, let's just say, about five years ago when the utilization of imaging was far less than 10%. In summary then, the integration of intravascular imaging in PCI unequivocally is associated with improvements in both the earlier procedural, but also the early clinical and late-term clinical outcomes compared with a reliance on angiography alone. And along with an evolution of the evidence basis, there is also the advancement of guidelines and education, just as recent as this past month for the European guidelines as I've shared with you, to promote intravascular imaging as a standard of care. The application of newer technologies with imaging will only complement conventional imaging with physiologic assessment, plaque characterization will further inform the precision of PCI and help standardize practices, and the Cath PCI registry is responsive to that and sensitive to that in collecting this information and evolving with it as well. So thank you very much for, again, being with us today, and we'll open to questions, Connie? Yeah, absolutely. Thank you. Okay, so some of the top questions are, getting insurance authorization is extremely difficult for CTA. Do you have any insight to help these get approved? Yes. So the authorization for non-invasive coronary CT angiography is truly a work in progress and evolution. It's markedly improved today compared with where we were, as I suggested, five years ago, even when it was starting to increase in 2019. And it very much varies on your insurer, of course, and your geography for the insurer. So it could be the same insurer but very different in the southeast compared to the Midwest. Having said that, I will only share with you my experience in Atlanta, where CT angiography is becoming increasingly reimbursed with little pushback from insurers in individuals who have chest pain symptoms or who have an abnormal stress test. But the one area where it is still quite challenging, if not altogether formidable to receive reimbursement, is in, let's say, a high-risk individual, a diabetic with smoking history and poorly controlled lipids, who might not have conventional or typical symptoms of ischemic heart disease, but we want to know whether there is disease or not. At least what our institution has done in those instances is provided a flat fee, and many of you may have done the same, of $500. The scan is typically far more than that, and it's cost a multiple of that. But we limited the cost to that so that if individuals do wish to pay, which is oftentimes less than their co-pay, that they're oftentimes willing to do it. It gets even more complicated when CTFFR is applied. My last comment about reimbursement. But the good news here is just within the past few months, there has been a change in reimbursement coding for that, and higher reimbursement now for the performance of CTFFR with the CT angiogram results. Staying on the subject of CTA, who should be reading the CCTA? And how do we convince our radiologists to give it up? Do radiologists read it? No, absolutely. No, and this is a historical dilemma from peripheral procedures, is it the vascular surgeon or the cardiologist or the radiologist, now to imaging as well. There are hospitals certainly across the United States that are reading, where the radiologists are not only reading the calcium score studies, but also the coronary CT angiograms. And it's truly a case-by-case, a hospital-by-hospital example. Even within our, as I shared, our 23 hospital healthcare system, there are a couple hospitals still where the radiologists are reading these studies. To be sure, I think the evolution here is more for cardiologists to be reading these because cardiologists coming out of fellowship training are now board-certified in CT imaging. And with the application of these more advanced modalities, what I'm seeing, at least in the United States, is that in centers where this is done by the non-cardiology discipline, namely radiologists, that you're seeing less application of CTFFR or plaque characterization, which is really kind of the future and the evolution of this. And so, I think it will be a natural segue that it will go more towards cardiology and less from radiology. But the last component I'll say about it is that for each individual's hospital, it's really a discussion with your hospital leadership, the administrative leadership, to not take away necessarily from the radiologist, but to enable the cardiologist to also read and, in part, by referrals, it'll be a natural evolution for the cardiologist to do so. All right. Two more questions on CCTA. Is the presence of calcium alone enough for insurance to approve a CCTA, and should we limit who can order the test? Two terrific questions. The presence of calcification alone won't justify reimbursement for the performance of a coronary CT angiogram, if I understand the question correctly. I'm going to deviate from the question, too, and just say that historically, an extensive calcium burden, let's just say numerically over 400, oftentimes precluded the performance of coronary CT angiography because you couldn't—it was too much of a blur, and it would obscure image interpretation. But now, with higher-fidelity scanners and the application of CTFFR, we're performing CT angiograms even on individuals with scores that well exceed 1,000. So the presence of calcium might not justify from an insurer basis the performance of CTA, but it won't prohibit your decision to do so. And then in terms of who might refer patients for this, right now, we don't have—we're not in an era of appropriateness. We have a lot of appropriateness for PCI for imaging as well, but we don't have, at least to my awareness, a lot of appropriateness criteria around referral for CT angiography. My opinion is that, you know, a rising tide raises all ships here, and that more people, general practitioners, internists, family doctors, and others who are interested in the well-being of their high-risk patients, if they're willing and able to refer patients for CT angiography, I'm supportive of that. All right, let's shift over to intraprocedure imaging. And just as an aside, the questions on CT angiography, it highlights your interest, but the increasing prevalence of this in the United States as well. Yeah. Sorry. No, you're good. Should all patients receive intra-PCI imaging, or is this more focused on high-risk PCI? Yeah, that's terrific. So the focus historically in the ACC Interventional Council has been at least to begin or endorse the use of intravascular imaging in complex or high-risk PCI procedures. But the benefit, to be sure, is not limited to those patients. Simple lesion characteristics still would benefit for all the reasons I shared with you all on the use of imaging to ensure that we're appropriately covering all of the disease that we might miss by angiography alone, that we are achieving adequate and or optimal stent expansion as well. I would just say that this whole story, just to go back for a brief moment anecdotally with CT angiography, has really highlighted in some ways too the limitations of conventional cardiac cath angiography alone, where we have patients who will come in with an abnormal CT angiogram, they have plaque in a vessel, they have an abnormal CT FFR. And just as one of the earlier examples I shared with you all this morning, we perform an angiogram and it really doesn't look bad at all. And we say, ah, this is overestimated by the CT angiogram. But just for, not for fun, but just for confirmatory purposes, I'll perform an FFR. And indeed, it may be significant in some of these cases, and it's not until we perform intravascular imaging that we identify, hey, there is severe disease in the proximal left anterior descending artery. And those are instances in which I wouldn't characterize that as a high-risk case, but it's an instance in which intravascular imaging also benefited the patient, in this instance, prior to the procedure, but also during the procedure as well. So I would suggest expanding it to all lesions, but if we're going to start somewhere and encourage physicians to adopt this in a more routine, broader fashion, at a minimum with complex PCI. And is there an advantage to OCT over IVUS or vice versa? Yes, this is a topical issue because clinical trial data would not suggest that there's necessarily a benefit with one or the other. It's really just applying intravascular imaging and acting appropriately on it is going to afford the best outcomes. Each of these two technologies have their own advantages and disadvantages. Certainly the resolution, the image resolution, fidelity with OCT is far greater. Plat characterization arguably may be a little bit better with OCT compared with intravascular ultrasound, but OCT, on the other hand, has its limitations where it requires a contrast injection with every image assessment, ascertainment, and that can create challenges for patients with chronic kidney disease. It's also limited for the assessment of osteolesians, because of flow around it and needing what we term a bloodless field. Intravascular ultrasound, on the other hand, is by far the majority of intravascular imaging, both in the United States and abroad. OCT, I won't say has been reserved for clinical trials, but largely has been for stent trials instead. And IVUS is also improving. There's now what's termed high definition or HD-IVUS that, like RTVs, is providing a higher HD quality as well with higher frequency. All right, so now two questions about stress testing and then interprocedural testing. What is your opinion regarding the need for FFR if you do not have a positive stress test prior to left heart cath? I'm not sure why they'd be in the lab. Yeah, so, well, there are many instances too, of course, where individuals persist with chest pain symptoms or ischemic symptoms with a negative stress test. And as I shared with you all earlier this morning, there are certainly limitations of stress testing. And so it's not a perfect study, and the gold standard would be to perform angiography. And I would say that, historically, we would say the gold standard is to perform a cardiac catheterization. I would argue it's now beyond that. It's to perform a cardiac catheterization with either imaging or, more commonly, hemodynamic assessment. I don't believe that there are some instances in which the disease severity is unequivocally severe and needs to be treated. I think, certainly, if there are patients with chest pain symptoms and intermediate disease, we can perform fractional flow reserve to confirm the functional significance or not. And then there are other instances. Many of you have heard of the term minoco or myocardial ischemia with non-obstructive coronary arteries, both prevalent in men and women, but it's more prevalent in women. This is something where we're now looking at coronary flow within the level of the myocardium and the microvascular resistance as well. And if the IVAS result does not match the stress test results, do you still perform a PCI? Or one might say, would you not perform PCI then? Like, it could go either way, right? Yeah, no, to be sure, couple of things. One is to be sure the measurements we're performing now in the cath lab, in my opinion, far trump the non-invasive stress test results. I'm speaking in generalities, of course, but if you have a significant FFR in a lesion and the stress test result is negative and the patient's symptomatic and we can improve the patient's quality of life, we're gonna treat the vessel based on our measurements in the cath lab, not on the stress test, given the limitations of non-invasive stress testing I was sharing before. The other thing is that, this is getting a bit beyond the scope, but we always say treat the patient, not the number. So if we use 0.80 as a criterion for functional significance and you've got somebody with clear symptoms and a clear lesion, and let's just say the FFR is 0.81, right, you can't let this go. And you've gotta treat the patient in the context of the patient's clinical presentation and syndrome over just one singular measurement. And everyone wants to know, for STEMIs, would you recommend balloon angioplasty first before using IVUS? Yes, I would. And as a generality, I think in most instances, yes. We wanna restore flow in the artery and achieve reperfusion, that's our principal goal. And then we can perform intravascular imaging to inform next steps. Okay. And then will the NCDR consider collecting intravascular imaging before, during, and after the procedure to support the research presented here? So I'll take a stab at this. So the CAF PCI dataset will begin a revision process sometime next year, and hopefully we'll be able to roll that out in 2026. And of course, when the work group evaluates imaging, they'll be looking at all of the recent shifts in practice trends and all of that and take that into account. So as you know, when we collect intra-procedure imaging right now, we're handicapped, right? We don't know anything about it. We don't know if it was used prior to the intervention, immediately after, it's only added as yet another device on the procedure. And then if the procedure was abandoned for any reason and a device was not deployed, then you don't even know, or we can't collect that it was used as maybe a decision to that end. So I would imagine, but don't know for sure, that that portion of data collection will be expanded to better understand how and when intra-procedure imaging is used. I think the work group charge will be to update the data set to reflect the current science and so that we can learn more about what's happening. And then once we collect the data, then we can report different metrics and understand more. I don't know if it will align with the research that we heard about today, but for sure it's an area that I think will, ooh, sorry. It's an area that I think will really be of high interest to the work group. And then the steering committee, of course, is the first to review what the data set work group develops. And usually there's a representative from the steering committee there. And then those two work groups or committees together present the copy that you then see in the open comment and where all of your clinicians and you get to comment on it and provide feedback. Just to expand on that too, I think that the steering committee would highly endorse that collection of which stage of the procedure, before, during, after it's being performed. Principally because in every case differs, but if you had to say when's the most important time to use intravascular imaging, there is no right answer because it's depending on patient to patient. But as a generality, it would be after the stent is deployed for all the reasons I mentioned, that we wanna make sure that the stent is fully expanded, that we've covered all of the disease, that there's no malapposition. And as an example, in one of the large trials that I shared with you, an international randomized trial, and actually the one that tipped the scale for the ESC to change now their recommendation to 1A, it's called Renovate PCI. In that trial, for the patients randomized to intravascular imaging, and they could use OCT or IVUS, and it turns out the meta-analysis and the trials, just to repeat, showed no benefit, it's just use one and know what you're looking at. But in that trial, if you were randomized to intravascular imaging as a patient and as an operator, you weren't mandated when you had to use it, you just had to use it at some point in that procedure. And about a third of the time, it was used before the stent was deployed, and it was used in all of the cases after the stent was deployed. So how that folds out into real-world clinical practice, I think will be something exciting for us to see. Okay, our cardiologists use advanced imaging in the cath lab on almost all cases. However, they do not often provide pre-PCI results. They have said that post-PCI results are most important. Any suggestions on how to convince them of the need for pre-PCI measurements? It's, maybe if you just asked that before my comments, because it's really, there's a lot of discretion here, and although it can certainly inform the pre-treatment component, many of us might say it's not necessarily mandatory, or that we need to convince all the operators to do it at that point, but at least certainly at the end of the procedure too. But it doesn't, by all means, it doesn't discount using it beforehand as well. For abstraction purposes, will there be a change in include use of these measures intra and post-intervention? So I don't think we can report any more than we are right now, which is utilization, because we only know that it was used during the procedure. And the other question is, would the NCDR consider creating a report linking complex disease and the use of intravascular imaging on the executive summary report? That is an interesting idea. We could probably get close to that, because we collect chronic total occlusions and high calcium lesions, et cetera, so interesting idea. And the use of other adjunctive modalities like atherectomy or intravascular lithotripsy that we're collecting now could be paired with that too. Right, right, yes, interesting idea. Make a note of that, please. Done. Okay. Do you have data on the reduction of in stent restenosis with the use of IVUS? I thought that was part of- Yes, very much so. About a 30% reduction in restenosis when imaging is used. Okay. Best stress imaging study for patients with reoccurring angina, prior PCI, and possible in stent restenosis? Ooh. My, I think, and maybe the generalities of practice would also support this, but if it's available, cardiac MRI has a very high accuracy as a non-invasive stress test, and what I really like about cardiac MRI, this is now the art of medicine, not the science, so I'm just speaking from my own opinions, but cardiac MRI is very good too at localizing the disease. So oftentimes we'll see in non-invasive nuclear stress testing an individual has anterior ischemia, and the lesion is in the right coronary artery that's supplied the inferior wall, and the LAD looks just fine, right? And cardiac MRI is very, very precise in not only identifying ischemia, but localizing it to the territory so that we can align it with the coronary angiogram. Let's see, will we see a change in AUC metrics to incorporate CTFFR for the elective patients as appropriate without a stress test? Do you have any insight to the AUC? I do not. Yeah, and I don't either right now. They are in the process of being updated, and I can't imagine that they wouldn't consider this. I would agree. I would think that would be supported. Yeah. Hope that would be supported. Exactly. Our interventional cardiologists seem to need education on the physics and proper use and interpretation of IVUS. What is the best remedy for this? Well, one is attendance at meetings like this, right, where we share the evidence basis and the clinical benefit. The other is, if I'll pause for a moment, I know we've got just a couple moments left, but we looked at, on a broader scale, we looked recently at how we're performing education for physicians, interventional cardiologists across the United States and the world, and we looked at impact, the impact factor of different interventions. So webcasts, a news flyer sent to your home mailbox, to scientific sessions, to programs where we're sponsored by industry, to guidelines and to large, high-impact journal manuscripts. And the highest level of impact for how a physician changes his or her behaviors and practice is driven by guidelines and driven by large, high-impact clinical trials. But the greatest predictor, beyond any of things I've mentioned, in how a physician changes his or her practice is what the guy or gal is doing next to you in the cath lab or in the clinic room. And so oftentimes, once one individual in a program starts applying good practices, others will follow suit. Aside from that, as the ACC Interventional Council indicates, too, there's a need for education about image interpretation. As I mentioned, these things don't work or benefit just by putting them down the coronary artery. You have to understand it and act upon it. And attendance at medical meetings, both regional and national and international, continue to focus on this as well. Can they invite you over? Sure, but now online education, too, is now supplanting a lot of these major meetings, and so it's even more readily available to all of us. It sounds like a physician champion might help, right? Just making buddies with one guy to help. As with most things, absolutely. A physician champion is the right term. Do you have a non-invasive imaging selection algorithm that aids in selection based on the patient presentation or other factors? No, at least at our program, we do not. It's largely based on the discretion of the treating physician, how he or she would elect to proceed with risk assessment for the patients. It's still very much individualized. Like many institutions, as we've shared, it's moving now away from the nuclear stress test, which really deliver a large amount of radiation, especially to women, when we consider breast tissue, to cardiac MRI, to CT angiography, which now can be performed with exceptionally low radiation, exposure, and stress echocardiography. And how is the NCDR-Cath PCI registry capturing the intra and post-procedure IVUS or other imaging? Again, that's just on the device list. That's the limit of what we can do right now. Can you explain why it is not necessary to trend with high-sensitivity troponin? It's not necessary. I think many institutions still do trend with high-sensitivity troponin. I'd say it's probably more the commonality rather than the exception to not. High-sensitivity troponin really is challenging, right, for us in healthcare systems, not to mention in clinical trials on what defines myocardial infarction, because so many people now come in with this vague, ambiguous result. And so, therefore, there is a need to trend it to see if it's continuing to escalate or not. Sorry, my questions are moving here. In your opinion, CTA-FFR is increasing the number of cases referred to cath or less? It's exactly the experience I shared with you from the United Kingdom. If we look at the performance of invasive angiography, it's really plateauing, and that's because, on the one hand, CT angiography being performed on a lot of, let's say, perceived lower-risk patients will have normal coronary arteries and, therefore, not need to go on to invasive angiography. So that would decline the performance of cardiac cath, right? But on the other hand, more patients are being identified with significant disease that might not have been manifest by non-invasive testing or by assessment of routine symptoms, or there may be ambiguity in the severity of their disease by the CT angiogram with calcium-obscuring image interpretation. And finally, there may be individuals with abnormal CT-FFR results, so that's raising the performance of invasive angiography, and altogether, it's kind of balancing it out for an equal number of procedures. Part of the reason that we have, in the United States, uniquely dilemmas with reimbursement for CT angiography has been a trial conducted by my former colleague at Duke, Pam Douglas, which was a large randomized trial called PROMIS that looked at nuclear stress testing versus CT angiography. And from an insurer's perspective, survival was similar, but CT angiography led, in that instance, to more cardiac catheterization procedures. I think that was also a nascent time in our understanding of CT angiography, and so an insurer might say, well, if it's not improving outcome and it's leading to more procedures, it's not going to be reimbursed. And other trials since that time have demonstrated a completely different result, and therefore, we've seen it be a more routine assessment and standard of care in other geographies before now becoming in the US. So we have just 30 seconds left. Will you come back? Oh, 1,000%, yeah. I've enjoyed my time with you all. And these are terrific questions. Thank you for your interest in asking them. Can I tell a secret? Okay, now I'm nervous again. So you told me that you like to work out on the Peloton. Yes. What do you make your children do? Well, you know the answer to this, but my kids are very successful alpine climbers, mountaineering people, and so we were climbing recently in Europe. We were summoning the Matterhorn, and my son did it in the ninth fastest time in recent recorded history. And so the weekend before we were doing that, he was running a 17-mile race at 14,000 feet. He lives in Boulder, Colorado. My daughter had done an Ironman triathlon the weekend before, but I did 30 minutes on the Peloton with Jen Sherman. So you can see the level of fitness was very equivalent. And that's why I stayed at the bottom and didn't make it to the top, and they did. So yeah, lesson learned. Thank you very much for being here. Yeah, thanks everybody. Thank you.

intravascular imaging

percutaneous coronary intervention

IVUS

OCT

cardiovascular care

imaging techniques

regulatory challenges

non-invasive imaging

coronary CT angiography