Thank you so much for inviting me to join you today. It's amazing to see this wonderful group back together again. I'm gonna talk about IVAS and OCT imaging in PCI. So we all know that angiography has its inherent limitations. It's a planar projection of the coronary tree and we don't have the ability to directly visualize the vessel wall. And so we have intravascular imaging, IVAS and OCT, which allow us to do that. And we are able to get cross-sectional tomographic images. We could spend a lot of time talking about the relative merits of each in terms of how well they're able to see different lesion characteristics. But in the big picture, OCT allows us to have a lot more axial resolution, 10 to 20 microns compared to IVAS, which is 50 to 150, although it has a shallower penetration depth and blood clearance is required. So that has its limitations in osteal disease. The new guidelines have three specific recommendations about the use of IVAS and OCT in PCI procedural performance. I'm gonna go through the key data behind each one. The first one is a 2A recommendation, level of evidence B randomized. And this is stating that IVAS can be useful for procedural guidance, particularly in cases of left main or complex coronary artery stenting to reduce ischemic events. Let's start with the ultimate trial that randomized 1,448 patients to either IVAS or angiography guided drug looting stent implantation. And at 12 months, they saw that their primary endpoint, target vessel failure, which was a combination of cardiac death, target vessel MI and TBR, the IVAS group did better. And when they looked at within this IVAS group, they stratified them into two groups, what they call the optimal PCI group and the suboptimal. And the way they defined optimal PCI was an MLA more than five or 90% of the MLA of the distal reference vessel and less than 50% plaque burden within five millimeters of the stent edges and no edge dissection longer than three millimeters. And when they looked at this group, the optimal PCI group, those also did better in terms of one year target vessel failure compared to the suboptimal group. And out to three years, we saw those consistent results with the IVAS guidance group at still 6.6% of the target vessel failure compared to 10.7% in the angioguided arm and consistent results in the optimal PCI versus suboptimal arm. The IVAS-XPL trial was another study looking at IVAS versus angiographic guidance for drug loading stent implantation. This was a study of 1400 patients and there were very long coronary lesions in this study. The average stent length was 39 millimeters. And at 12 months, they saw a 2.9% absolute reduction in MACE driven by TLR and the IVAS group. Now in left main, there've been some studies looking at IVAS specifically in the NOBLE trial which randomized patients to PCI versus CABG. There were 25 patients who received IVAS out of the 603 in the PCI arm. Compared those who received IVAS and those who did not, they saw no difference at five years in terms of MACE. However, TLR was lower in the IVAS arm compared to those who did not receive IVAS. And in the XL trial, also looking at PCI versus CABG in left main, 722 of the 948 in the PCI arm received IVAS as part of their procedure. And what they did for this study was divided the MSA ranges into tertiles. And then they compared the smallest to the largest tertile. And they saw at three years, the combined event rate for death, MI and stroke was significantly different for the smallest compared to the largest tertile. Now in the CTO IVAS study, there were 402 patients with CTOs who were randomized to either IVAS or angioguided PCI. And here they found out to 12 months that MACE was improved significantly in the IVAS guided group, as well as the composite of cardiac death and MI. And while target vessel revascularization was lower in a percentage, it was not statistically significant in this group. There have been a number of meta-analyses looking at IVAS versus angiography, some including up to 31 different studies, including over 29,000 patients. And across the board, the theme is that IVAS has shown a reduction in MACE, specifically with advantages and complex lesions. One of the most recent studies, meta-analyses by Bukhari et al, on the right-hand side, you can see a figure here, shows an improvement with the use of IVAS. Although if you focus on the all-cause death here, when they limited their study to only the RCTs, the all-cause death effect was neutralized. And that's why we have the indication in the recommendation for the reduction of ischemic events. So the second recommendation is a two-way level of evidence B randomized. And this is basically saying that OCT is a reasonable alternative to IVAS for procedural guidance, except in osteolefemain disease. The Illumion-3 trial randomized patients to OCT versus IVAS versus angioguided PCI. There were 450 patients included in the study, and their primary endpoint was post-PCI MSA. They basically found that OCT was non-inferior to IVAS, but it was not superior to IVAS and also not superior to angioguidance, but there was no difference in procedural MACE. The doctor study included 240 patients with non-ST elevation ACS. And in this study, they compared angiography-guided PCI to OCT-guided PCI. And their primary endpoint in the study was FFR. They found that the OCT group had a slightly higher FFR after the procedure, 0.94 compared to 0.92. The use of OCT changed the treatment strategy in 50% of these cases. And some of the most common findings they found in post-PCI OCT were stent under-expansion, stent malposition, and edge dissection. And despite longer procedure time and more contrast, acute kidney injury was the same at six months. The opinion trial was a study of 829 patients comparing OCT to IVAS. Their primary endpoint at 12 months was target vessel failure. And this was a composite of cardiac death, target vessel MI, ischemia-driven target vessel revascularization. And they found non-inferiority for OCT compared to IVAS. They also had a secondary endpoint at eight months. They brought patients back for angiography and looked for resynosis and basically found no difference. And it was 89% of their patients they were able to bring back for angiography. The final recommendation is a two-way level of evidence C limited data recommendation for the use of IVAS or OCT for determining the mechanism of stent failure. Now, it's unlikely we're ever gonna have a large randomized trial of these patients, but we do know that there are a number of different mechanisms that we can identify with both IVAS and OCT to understand reasons for resynosis. Mechanical factors and technical factors, including stent under-expansion, stent fracture, gaps, residual uncovered plaques. There was a sub-study of the HORIZONS-AMI trial looking specifically at stent thrombosis. And out of their 389 patients who received IVAS, 12 of them had early stent thrombosis after acute MI. And when they compared these two groups, they saw that the stent thrombosis group had a smaller final lumen area, as well as inflow and outflow disease, residual stenosis or dissection. Interestingly, they didn't see a difference in, a statistical difference in malapposition. There was a large registry, the Pesto-French Registry of Stent Thrombosis, including 120 patients. 82% of these patients had STEMI, the rest were NSTEMI. 59% had drug-eluting stents, the rest were bare metal stents, and there were 2% BVS. And in this group, OCT identified the cause of the stent thrombosis in 97% of the cases. 63%, they found that they all had discontinued their antiplatelet therapy within the first month. They divided these patients into groups with very late stent thrombosis and late stent thrombosis, compared to those with subacute or acute, and found that the most common reasons in very late and late stent thrombosis were malapposition and neo-atherosclerosis, whereas in the subacute and the acute groups, they found mostly malapposition under expansion. So in summary, IVUS is useful for PCI optimization, particularly in left main or complex coronary stenting. OCT is also a useful alternative to IVUS with the exception of osteoleft-main disease. Both are useful for identifying cause of stent failure. And ultimately, both are very useful for growing our armamentarium of tools, for improving our outcomes after PCI. And it'll be very interesting to see over time how we integrate the use of both anatomic and functional measures as we try to improve our PCI outcomes. Thank you very much.

intravascular imaging

PCI

IVUS

OCT

angiography limitations