Amulet or Watchman Device for Percutaneous Left Atrial Appendage Closure: Primary Results of the SWISS-APERO Randomized Clinical Trial

{BACKGROUND: No study has so far compared Amulet with the new Watchman FLX in terms of residual left atrial appendage (LAA) patency or clinical outcomes in patients undergoing percutaneous LAA closure. METHODS: In the investigator-initiated SWISS APERO trial (Comparison of Amulet Versus Watchman/FLX Device in Patients Undergoing Left Atrial Appendage Closure), patients undergoing LAA closure were randomly assigned (1:1) open label to receive Amulet or Watchman 2.5 or FLX (Watchman) across 8 European centers. The primary end point was the composite of justified crossover to a nonrandomized device during LAA closure procedure or residual LAA patency detected by cardiac computed tomography angiography (CCTA) at 45 days. The secondary end points included procedural complications, device-related thrombus, peridevice leak at transesophageal echocardiography, and clinical outcomes at 45 days. Results: Between June 2018 and May 2021, 221 patients were randomly assigned to Amulet (111 [50.2%]) or Watchman (110 [49.8%]), of whom 25 (22.7%) patients included before October 2019 received Watchman 2.5, and 85 (77.3%) patients received Watchman FLX. The primary end point was assessable in 205 (92.8%) patients and occurred in 71 (67.6%) patients receiving Amulet and 70 (70.0%) patients receiving Watchman, respectively (risk ratio, 0.97 [95% CI, 0.80-1.16]; P=0.713). A single justified crossover occurred in a patient with Amulet who fulfilled LAA patency criteria at 45-day CCTA. Major procedure-related complications occurred more frequently in the Amulet group (9.0% versus 2.7%; P=0.047) because of more frequent bleeding (7.2% versus 1.8%). At 45 days, the peridevice leak rate at transesophageal echocardiography was higher with Watchman than with Amulet (27.5% versus 13.7%