Abstract 12967: Early Gastrointestinal Bleeding is Most Common Hemorrhagic Complication After Watchman Implantation

Introduction: Left atrial appendage occlusion (LAAO) with the Watchman device is increasingly used for patients with an indication for anticoagulation for atrial fibrillation (AF) and a contraindication to long term anticoagulation. Real world early outcomes in this high-risk patient population are scarce. Methods: We retrospectively evaluated a healthcare system registry of 1200 patients who underwent LAAO with Watchman 2.5 or FLX between 10/2018 and 8/2021 and included 849 patients with 6-month follow-up. We classified complications in 3 distinct categories (immediate procedural, 6-week post-procedural and 6-month post-procedural) and tracked all thromboembolism, hemorrhage and mortality that occurred after the immediate procedural complications. Results: Mean age was 77.6 ± 8.3 years old, 49% were female, 68% had paroxysmal AF, mean CHA 2 DS 2 -VASc was 5.0 ± 1.4, and mean HAS-BLED was 2.9 ± 1.0. Immediate procedural complication rate was 2.4% (access site n=16; tamponade n=2; esophageal injury n=2). 6-week post-procedural complication rate was 4.2% whereas 6-month post-procedural complication rate was 2.0% (% per 100 patient-months). Overall post-procedural complication rate after 6.2 ± 1.1 months was 2.6% of which 0.3% were thromboembolic, 1.2% were hemorrhagic and 1.1% were mortality events (% per 100 patient-months). Gastrointestinal bleeding (GIB) made up 39% and 83% of post-procedural and hemorrhagic complications respectively. Time-indexed post-procedural GIB rate was higher during 6-week period compared to 6-month period (1.9% vs. 0.7%, p=0.00003). Patients with most common indication for LAAO (high risk for bleeding or history of major bleeding, 82.0%) had higher odds of post-procedural GIB than those without bleeding indication (7.0% vs. 2.6%, OR=2.8, p=0.02). GIB was not significantly associated with mortality. Conclusions: Post-LAAO complication rate was low and decreased over time when comparing 6-week and 6-month periods in a high-risk patient population. Early GIB was the most common hemorrhagic complication and patients with bleeding indication for LAAO had a higher risk of GIB within the first 6 months after procedure. Further studies targeting ideal antithrombotic regimen after Watchman implantation are needed.