Ticagrelor Sans Aspirin Trial Answers Some Questions About DAPT

This transcript has been edited for clarity.
Hi. My name is Robert Byrne. I'm an interventional cardiologist at the German Heart Center in Munich and am here at TCT 2019 in San Francisco, where we've seen some interesting results from the TWILIGHT study. I would like to discuss some of the implications of this study for clinical practice.
TWILIGHT looked at patients who underwent PCI, and at 3 months they were randomized to ticagrelor plus aspirin or ticagrelor plus placebo. It was a large-scale trial with more than 9000 patients and has many high-quality features, including double-blind design and event adjudication. It really was an impressive feat.
The main result showed a clear reduction in bleeding, without any price to pay in terms of ischemic complications with ticagrelor monotherapy. How do we implement these results into our everyday clinical practice? While the data clear up some issues, they also raises some new questions for me.

First, it was predominantly a trial of patients with acute coronary syndrome. In those patients on ticagrelor plus aspirin who are event-free at 3 months, there is now a strong rationale to leave aspirin out and continue them on ticagrelor monotherapy because I think the data are quite convincing.
However, you will be aware that recently we had data from a head-to-head trial, ISAR-REACT 5, by investigators from our research group in Munich, who showed that in acute coronary syndrome (ACS), prasugrel seemed to have an edge over ticagrelor. We've already started to migrate our ACS patients to prasugrel, and it's hard to know how to apply these data to those patients. I think it would be a stretch to switch the patients on prasugrel and aspirin to ticagrelor monotherapy at 3 months, though, of course, you might consider it on a case-by-case basis.
The second thing that we think about is the generalizability of these results for all of the patients that we see. An important feature of this study—you could certainly say it's a strength but it's not without its limitations—is that patients were enrolled after a 3-month run-in period, so patients who had events in the early phase were weeded out, if you like, and aren't represented in the randomized trial dataset. I think this is important to realize when we interpret the data.
The other issue is what to do with patients who are on clopidogrel. Similar to what I said in relation to patients who reach the 3-month time point on prasugrel, it's difficult to know how these study results apply to the clopidogrel patients. According to guidelines, all acute coronary syndrome patients who don't have a contraindication should be on the more potent P2Y12 inhibitors, but we do realize that in certain countries where there are reimbursement issues, some patients can deescalate to clopidogrel, quite soon after hospital discharge. We also saw a number of studies supporting this approach, from TROPICAL-ACS to TOPIC. Perhaps a proportion of patients in our practice will reach this 3-month time period after intervention on clopidogrel, so it's difficult to know how these results apply to those patients.
The final question that's thrown up by the results of this provocative and very well-done clinical trial is, what do we do with patients in the long term? If we have patients who have undergone complex interventions with acute coronary syndrome and, after 3 months, we de-escalate them from aspirin and ticagrelor to ticagrelor monotherapy, what do we do when the 12- or 15-month period is over?
Do we leave patients on ticagrelor, perhaps on a PEGASUS dose of 60 mg twice a day, or do we switch them back to aspirin monotherapy for long-term secondary prevention?
In summary, I think TWILIGHT was the most important trial presented at TCT 2019. Certainly, the results are of relevance to the cardiology community and they will impact the next clinical practice guidelines, but there are a number of questions that we need to have clarification on before we can fully decide how best to implement these findings in clinical practice.