Incidence and Clinical Impact of Major Bleeding Following Left Atrial Appendage Occlusion: Insights from the Amplatzer™ Amulet™ LAA Occluder Observational Study.

Background Major bleeding (MB) events are independent predictors of mortality after cardiac interventional procedures. The clinical relevance of MB following left atrial appendage occlusion (LAAO) remains unclear. Aims This study aimed to investigate the incidence and clinical impact of MB after LAAO in a real-world population at high-risk for bleeding and contraindicated to anticoagulation. Methods The 2-year results of the Amplatzer™ Amulet™ Occluder Observational Study were analyzed. An independent committee adjudicated MBs according to the Bleeding Academic Research Consortium scale. Cox proportional hazards regression identified variables associated with MB events and mortality. Results The MB rate was 7.2%/year, with a rate of 10.1%/year during year one, decreasing to 4.0%/year over year two. The most common bleeding location was gastrointestinal, accounting for 48% of MBs. Pre-LAAO MB was associated with an increased risk for post-LAAO MB (HR 2.34; 95% CI 1.37-3.99). The occurrence of post-LAAO MB was associated with increased mortality (37.3% vs 12.7%; pl0.0001), mainly driven by events occurring beyond the peri-procedural period. The annualized rate of ischemic stroke or TIA was similar in patients with and without MB (2.3% vs 3.3%; p=0.446). MB post-LAAO was a strong independent predictor of mortality (HR 3.07; 95% CI 2.15-4.40). Conclusions In real-world patients at high bleeding risk, MB following LAAO was not uncommon and associated with a significant increase in mortality, without increasing the risk of stroke.