Pearls from: E. Magnus Ohman, MD

Dual antiplatelet therapy (DAPT) remains a question mark following percutaneous coronary intervention -- and it is getting harder every year to figure out the best course of DAPT for every patient, suggests E. Magnus Ohman, MD, of Duke University Medical Center in Durham, N.C.

In this exclusive MedPage Today video interview, the interventional cardiologist says that learning how to tailor DAPT duration and agents to each patient requires studying tens of thousands of them. The likelihood of being able to collect that much information grows more remote over time as the rate of stent thrombosis is dwindling every year, he notes. But electronic health records may help fill in some of the knowledge gaps.

Following is a transcript of his remarks:

It's complex. It's really quite complex now because on the one hand we have data to show that longer-term use of DAPT after PCI is a benefit, but there's also some risks for bleeding, in particular.

So the picture has to be almost individualized, which we, as physicians, are not so well equipped with. There have been studies done that highlight the certain characteristics of patients or procedure characteristics would favor a longer-term use, whereas other characteristics that really define bleeding would probably be better to sort of characterize patients that should receive it shorter. But exactly how to do that in practice and how to use these therapies is quite complex. So that's just on the duration.

Then you have the complexity of which type of agent, and we have a lot of experience with clopidogrel, but we know after ACS [acute coronary syndrome] that prasugrel and ticagrelor offers superior outcomes in PCI patients. Now how long you should use those, well, we have even less data than we have with clopidogrel to define exactly what to do. So the typical aspect would be that if patients come in with ACS, we try to focus on the more effective agents and use them for the full year of duration. But as I said earlier, there would be consideration for shortening the time, particularly with the newer stents available.

One of the challenges in this field is that to resolve the issue how long and which type of agent actually really requires lots and lots of patients studied in the order of 20,000 to 30,000 patients. So getting that information, what we really think would define the optimal strategy probably is unattainable because the rate of stent thrombosis is now so low in the range of 0.5% to 1% -- maybe a little bit higher after ST elevation MI -- that really to define this in clinical investigation becomes increasingly hard.

So in the future, we'll have to look at doing trials where we can collect information like this in tens of thousand of patients in a much, much easier way. I believe that there will be in the future some idea of collecting electronic health records that you can combine with the information from the procedure and what the patient is taking, but it's still a few years away for us to get to that ultimate knowledge base of how to use these agents.

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