Clinical Effectiveness of Transcatheter Left Atrial Appendage Occlusion With Watchman FLX Compared With First-Generation Watchman

BACKGROUND Procedural complications, device-related thrombus, and peridevice leak may limit the benefit of transcatheter left atrial appendage occlusion (LAAO). Although next-generation devices incorporate design modifications meant to address these phenomena, the longer term impact of these modifications on outcomes has not been described. OBJECTIVES The aim of this study was to compare 1-year safety and clinical effectiveness of the Watchman FLX with the predicate Watchman 2.5 device. METHODS The National Cardiovascular Data Registry LAAO Registry was used to identify: 1) patients who received the Watchman FLX; and 2) an identical number of patients receiving the Watchman 2.5 at the same sites directly preceding the first Watchman FLX case at each site. The primary endpoint was ischemic stroke. A secondary analysis was performed using 2:1 propensity score matching. RESULTS The study cohort consisted of 27,141 patients receiving each device. Among patients undergoing transesophageal echocardiography at 45 days, the rate of device-related thrombus was not different for Watchman FLX compared with Watchman 2.5 (0.4% vs 0.5%; P = 0.27) while the rate of any peridevice leak was significantly lower (14.7% vs 23.5%; P < 0.001). At 1 year, Watchman FLX was associated with a significantly lower risk for major adverse events (adjusted HR: 0.84; 95% CI: 0.80-0.88; P < 0.0001), ischemic stroke (adjusted HR: 0.82; 95% CI: 0.68-0.98; P = 0.02), and ischemic stroke or systemic embolism (adjusted HR: 0.74; 95% CI: 0.62-0.87; P = 0.0003). The findings of the propensity score matching analysis were similar. CONCLUSIONS Transcatheter LAAO with the Watchman FLX is associated with significantly lower risks for major adverse events and ischemic stroke at 1 year compared with the predicate Watchman device. These findings suggest that enhanced procedural safety and completeness of anatomical closure translate into better longer term safety and clinical effectiveness after transcatheter LAAO. (c) 2025 Published by Elsevier on behalf of the American College of Cardiology Foundation.