Listen to Dr. Evan Shlofmitz from St. Francis Hospital (Roslyn, NY) discuss the large data set showing the frequency of ISR and how imaging shows to be a critical piece in understanding and treating this complication.
So intravascular imaging based algorithm. I thought an alternate title for the talk could be stent failures. Why imaging should be mandatory for I. S. On it really is a second chance to get it right often. Um So we know from a jay's group, this was recently published where they looked at over 10,000 patients who have had a stent implantation to see what are the long term outcomes. And we know there's been significant advancement in stent design the drugs, the polymers, the strut thickness. But if you look at contemporary drug eluting stents event rates still is relatively high. 13.4% at five years after the first year of target lesion related events continue to recruit about 2% per year despite these high quality drug eluting stents. So if you think about that really one in eight patients that you treat with Pc. I will be back in five years with a stent related event. I don't really think that's acceptable contemporary practice. So we all feel that in our own practice we don't often encounter I. S. R. R. Patients don't come back with restenosis. But when you look on a large scale the U. S. Data or over 10% of P. C. I. S. In the U. S. Or for I. S. R. It's a very significant portion of the population and it's critical that one we prevent this and I believe imaging and physiology guided P. C. I. Is critical to achieve that. But when someone comes back with I. S. R. We need to give them every chance that's possible to avoid coming back with a future event because once someone has I. S. Are significantly worse adverse events associated with that we see here from the adapt es registry. The difference in red shows cases for de novo lesions. Then in blue you have the other way around. Red is with srp Ci and blues de novo and you see a significant difference and at one year there's 15% risk of target vessel failure in patients who have I. S. R. P. C. I. And if you compare that to the um data pooled analysis from Angie's group that it should before where that's the event rate at five years. Follow up. So now you have that same event rate at just one year follow up when someone is being treated for I. S. R. So the question is, you know, how often is inter vascular imaging being used when we're treating patients with I. S. R. This is from a large scale registry out of Korea. And they found that over 6000 patients when they looked at I. S. Are lesions only 20% of those lesions had misguided PC. I. The rest were all angio guided P. C. I. In a more recent analysis in the US and cases with recurrent I. S. Are so not even the first I. S. Are patients who were being treated with breaking therapy. Just a third of cases. Had intravascular imaging. When I was at the Washington hospital center I looked at our patients who were treated with I. S. R. Imaging is standard of care there. We had about two thirds of cases that were treated with this when looking at just I. S. R. And I looked at the last 1500 cases of I. S. R. Two referral center for IAS are and when I compare the avis to know I've this case, as you see, there's a significant difference in events at one year. Follow up and buy three years patients with angio guided treatment of eyes are nearly a 50% major adverse event rate. I think this really helps to highlight the impact of intravascular imaging with these lesions. Now, it's important to talk about how we classify instant re stenosis. The classic classification system was described in 1999. That was very important at the time and relevant for bare metal stents. And it was an angio based classification system. Talked about focal or diffuse patterns and you know, this is still being used today with contemporary drug eluting stents. And I believe that this isn't the best way to classify because we know there's different mechanisms of disease that can't be appreciated just on the angiogram and this, it's important to know if it's focal or diffuse, but it doesn't tell you how to address that I. S are and what the best sort of treatment is, for instance, in a recent publication looking at under relatable I. S. Are. They talk about the classification. They report the findings of focal diffuse patterns and you see here intravascular imaging in a recent study, less than a quarter percent of cases I think it's important that we change the way we describe bias are and you can't do that without intravascular imaging. Once you accept that I think we'll get better outcomes. Here's just a representative example of historic pathology showing three unique types of I. S. Are very different. I. S. Are different mechanisms and the different mechanisms should all be treated in unique ways. Now, fortunately we don't need to have hissed open to tell us what the mechanism of the I. S. R. Is. We can achieve this with intravascular imaging slide highlights the distribution with IV's on the right is with drug eluting stents. And you see the various mechanisms of I. S. R. And that this isn't all just falling in one box. There's different types. You can't appreciate it. From an angiogram alone, here's an example of an angiogram where there's I. S. Are in the L. A. D. From the angiogram I think would be very difficult to determine what the primary ideology is and what the best way to treat this. This is a patient who was referred for breaking therapy in this case we use O. C. T. To assess this. And if you see really how profound the under expansion is. We have distillate, we on the left, we have the distal reference the middle. We have the lesion when the N. S. A. And on the right is approximate reference. I used the soc tms to show you on the longitudinal profile. You see really where there is a dumbbell pattern here and this is a patient that could have been treated with breaky therapy if intravascular imaging wasn't performed. You see there's very little tissue and the primary ideology is under expansion and that's what needs to be addressed in order to get an adequate outcome. So we recently introduced a new proposal for a classification scheme for I. S. R. That's entirely based on intravascular imaging. It's important that we classify what the predominant ideology of I. S. R. Is because that's gonna be prescriptive and tell you what it's needed to best address that. So whether you're using I. V. S. R. O. C. T. The important thing is just using intravascular imaging on the left. We have an example of neo and demo hyperplasia. It's very homogeneous. Next to that is neo atherosclerosis. The two frames next to it are both neo atherosclerosis and it's important to distinguish which type because they're treated very differently if it's predominantly calcified or if it's more olympic neo atherosclerosis and then on the right extent under expansion. We often see this with multiple layers of stent and it's usually due to calcium. There's perry struck calcium because there's something that's inhibiting the stent from properly expanding. When the operator put it in the stent for the first time. It's critical. This needs to be addressed. You need to do a root cause analysis. You need to overcome that expansion before you put another layer of stent. And now we have tools that can readily treat this under expansion. We have a lot more devices available to us. It's important that we don't just keep adding another layer and create this onion effect with the vessel. So at ST Francis we're using an algorithmic approach. It's very prescriptive based on the intravascular imaging and it all starts with intravascular imaging to determine what the primary causes. What's the mechanism of that stent failure. And then we use that to do determine what the next best treatment is. But it doesn't stop there. You need to have follow up imaging after you've done that treatment to make sure you've actually achieved that because all I. S. R. Is very difficult. It's part of the reason why there's poor outcomes associated with I. F. I. S. R. And you need to have the serial imaging especially before you implant another layer. You need to make sure that you've overcome any under expansion so that you can make sure you're leaving them with a larger M. S. A. And that's gonna be the best thing you can do is to give them the best chance of not coming back to the lab in the near future. I think the take home message anytime we're treating. I. S. Our first thing is trying to prevent it in the first place. As you heard earlier in the day. Um routine intravascular imaging is probably the best way we can do that. All I. S. Are all D. S. I. S. R. Is definitely not the same and they should not be treated as one unique entity. And it's critical to use inter vascular imaging to identify what that mechanism is and not just determine what the mechanism is but really guide your treatment that we could overcome. That. Also important to identify the number of stent layers that's often not apparent just from the angiogram. And then you always want to ensure that you've achieved adequate stent expansion prior to implanting any additional stents.