The optimal duration of dual antiplatelet therapy following DES implantation is unknown and the subject of intense interest among cardiologists. “Sadly,” writes Peter Berger in an editorial in the New England Journal of Medicine, a study from Korea that attempts to shed light on this issue will “fail to inform physicians’ practice with any degree of confidence… It is an interim analysis of two ongoing, underpowered studies,” he writes.
In the paper by Park et al, presented today at the ACC in Atlanta and simultaneously published in NEJM, Korean researchers combined data from REAL-LATE and ZEST-LATE, two trials that randomized 2701 DES patients who were free of adverse events and major bleeding for at least 12 months after DES to receive either clopidogrel plus aspirin or aspirin alone. At two years there was no difference in the composite primary endpoint of MI or cardiac death (1.8% with dual therapy versus 1.2% with aspirin monotherapy, HR 1.65, CI 0.80-3.36, p=0.17), and there were no significant differences in any individual endpoint of interest.
Until better data becomes available, Berger writes that “it would seem wise to avoid the use of drug-eluting stents in patients in whom ‘prolonged’ use of clopidogrel is unlikely to be feasible or is problematic.”
Sanjay Kaul sent the following comment to CardioBrief:
“This study is limited by design flaws that include pooling data from a randomized control trial designed to compare DES with a registry in an open-label manner; enrolling low-risk patient population by excluding those with cardiac events 12-24 months prior to enrollment; overinflated estimates for power calculation (50% reduction in MI or cardiac death with clopidogrel plus aspirin not supported by evidence); unexpected signal for harm with DAPT which might be due to a play of chance or a bias introduced by the open label design. So what are we to make of an unexpected finding from an underpowered trial limited by design flaws? Not much! In my opinion, these types of studies should not be used for drawing inferences or guiding clinical practice”.
Filed under: Uncategorized
