SAN DIEGO – In patients with atrial fibrillation and stable coronary artery disease, a randomized trial of oral anticoagulation alone versus an anticoagulant plus a single antiplatelet agent failed to establish noninferiority of the single-agent approach. The trial could not demonstrate its primary endpoint of all-cause death, myocardial infarction, stroke, or systemic embolism.
But a secondary endpoint that included major bleeding did demonstrate equivalence, leading the researchers to suggest that oral anticoagulation (OAC) alone may be sufficient in most patients.
“Combined OAC and single antiplatelet therapy is unlikely to provide net clinical benefit over OAC alone. Thus, OAC alone might be reasonable for AF [atrial fibrillation] patients beyond 1 year after coronary stenting,” Yukiko Nakano, MD, of Kyoto (Japan) University Graduate School of Medicine, said during a press conference at the Transcatheter Cardiovascular Therapeutics annual meeting, sponsored by the Cardiovascular Research Foundation. The report was simultaneously published Sept. 24 in Circulation (doi: 10.1161/CIRCULATIONAHA.118.036768).
The results support the European Society of Cardiology practice guidelines, which recommend lifelong OAC without antiplatelet therapy. But physicians often continue to prescribe antiplatelet agents out of concern that stent thrombosis could occur if the therapy is stopped.
The study was stopped prematurely because of insufficient recruitment, which may have contributed to the failed primary endpoint. It’s a shortcoming that befalls many such studies, perhaps because cardiologists tend to be set in their ways when it comes to treatment of patients after a stent implant. “Cardiologists just think they know the answer, and they don’t want to expose their patients (to a clinical trial). They say, ‘I have my patients on whatever regimen. It seems to be working, and they’re not bleeding, so I don’t want to change it.’ This study suggests that we probably can stop one of the two (antiplatelet drugs) and get by with a single agent, and in this case they got by with no agent (in the monotherapy arm),” said C. Michael Gibson, MD, chief of clinical research in the division of cardiology at Beth Israel Deaconess Medical Center, Boston, who was a discussant at the press conference.
The study recruited 696 patients who were receiving OAC plus single antiplatelet therapy (SAPT) 1 year after receiving a stent. They were randomized 1:1 to continue combined therapy or to stop SAPT and then followed for a median of 2.5 years. A total of 74% of patients who received OAC alone were taking warfarin, while 26% were taking a direct oral anticoagulant. The SAPT group took aspirin or clopidogrel.
Overall, 15.7% of OAC patients experienced the primary endpoint, compared with 13.6% of the combined group (noninferiority P = .20). None of the individual components of the primary endpoint were statistically significantly different between the groups. International Society on Thrombosis and Haemostasis major bleeding and Thrombolysis in Myocardial Infarction major bleeding trended in favor of OAC alone. The secondary endpoint (primary endpoint plus major bleeding) achieved noninferiority, occurring in 19.5% of the OAC group and 19.4% of the combined therapy group (noninferiority P = .016; superiority P = .96).
Daiichi-Sankyo funded the trial. Dr. Nakano had no conflicts of interest. Dr. Gibson reported numerous financial ties to pharmaceutical companies, including Daiichi-Sankyo.