Is It Over for DAPT After Left Atrial Appendage Closure?

The SIMPLAAFY trial revealed that left atrial appendage (LAA) closure may simplify antithrombotic management, with reduced-dose non-vitamin K oral anticoagulants (NOACs) and aspirin performing similarly to traditional dual antiplatelet therapy (DAPT) in the first six months. Saibal Kar, MD, from Los Robles Hospital and Medical Center, presented the findings at the Transcatheter Cardiovascular Therapeutics annual conference.

The study, published concurrently in JAMA, included 1,857 patients with nonvalvular atrial fibrillation who underwent LAA occlusion using the Watchman FLX Pro device. Participants were divided into three groups: aspirin alone, initial DAPT followed by aspirin, or initial reduced-dose NOACs followed by aspirin. Over the six-month period, the incidence rate of combined all-cause death, stroke, systemic embolism, or major bleeding was lower with NOACs (5.1%) and aspirin (3.3%) compared to DAPT (6.9%).

Statistically, both NOACs and aspirin were found to be at least as effective as DAPT in preventing adverse events (risk ratio [RR] 0.75 for NOACs, 0.49 for aspirin, 95% CI 0.48-1.18). No excess stroke occurred at 6 months with aspirin or NOAC monotherapy regimens, although bleeds were more prevalent with these treatments compared to DAPT.

Low-dose NOAC therapy also showed the lowest incidence of device-related thrombus (0.9% vs 3.4% with DAPT and 2.7% with aspirin) at 45 days. However, the trial excluded high-risk populations, and the findings may not be generalizable to all LAA occluder implant patients. Additionally, the ANDES trial indicated that short-term NOACs were not superior to DAPT in preventing device-related thrombus at 60 days, with higher rates at 1 year (5.2% vs 2.3%, P=0.154).

While aspirin emerged as a potential winner based on SIMPLAAFY, the jury is still out on NOACs. The trial results provide guidance for the short-term antithrombotic management of LAA closure patients, but longer-term outcomes are yet to be determined.