3-Year Clinical Outcomes Comparing the Amulet vs Watchman FLX for Left Atrial Appendage Closure in Patients With Atrial Fibrillation Results From the SWISS-APERO Randomized Clinical Trial

Abstract

Background: No study thus far has compared Amulet with Watchman FLX for clinical outcomes beyond 1 year after percutaneous left atrial appendage closure (LAAC). Objectives: The goal of this study was to compare Amulet and Watchman FLX in terms of 3-year clinical outcomes. Methods: In the investigator-initiated SWISS-APERO (Comparison of Amplatzer Amulet and Watchman Device in Patients Undergoing Left Atrial Appendage Closure) trial, patients with atrial fibrillation and high bleeding risk undergoing LAAC were randomly assigned (1:1) to receive Amulet or Watchman/FLX across 8 centers. Study endpoint included the composite of cardiovascular death, stroke, transient ischemic attack, or systemic embolism at 3 years. Analyses were repeated in the as-treated (AT) and per-protocol (PP) populations. Results: Of the 221 patients randomized to treatment, 220 completed LAAC and 3 patients randomized to receive the Amulet device received the Watchman FLX device. The follow-up rate at 3 years was 96.4% in the Amulet group and 97.3% in the Watchman group. The composite ischemic endpoint occurred numerically less frequently in the Amulet group compared with the Watchman group (18.2% vs 31.0%; HR: 0.58; 95% CI: 0.33-1.03; P = 0.06). In both the AT (17.0% vs 31.1%; HR: 0.53; 95% CI: 0.30-0.96; P = 0.035) and PP (16.2% vs 29.2%; HR: 0.54; 95% CI: 0.29-1.00; P = 0.049) populations, the composite ischemic endpoint was significantly lower in the Amulet group compared with the Watchman group. Conclusions: At 3 years after LAAC, there was no significant difference in the ischemic risk between the Amulet and the Watchman FLX groups. The lower occurrence of the ischemic composite endpoint observed in the Amulet group in both the AT and PP analyses is hypothesis generating and emphasizes the need for further studies. (Comparison of Amplatzer Amulet and Watchman Device in Patients Undergoing Left Atrial Appendage Closure [SWISS-APERO]; NCT03399851). (c) 2025 by the American College of Cardiology Foundation.