Abstract 4367478: Enhanced Safety and Efficacy of Watchman FLX Versus Watchman 2.5 in Percutaneous Left Atrial Appendage Occlusion: An Updated Comprehensive Meta-Analysis

Background: Percutaneous left atrial appendage occlusion (LAAO) offers stroke prevention for patients with non-valvular atrial fibrillation. While the Watchman 2.5 device has been widely adopted, the newer-generation Watchman FLX has gained traction due to evidence suggesting improved outcomes. This updated meta-analysis evaluates and compares the clinical performance of the two devices. Methods: We systematically searched PubMed, Scopus, Web of Science, Embase, and the Cochrane Central Register of Controlled Trials from inception through April 13, 2025, for studies comparing the Watchman FLX and Watchman 2.5 devices. Primary outcomes included implantation success and a composite of major complications (death, stroke, and major bleeding) through final follow-up. Secondary outcomes included individual components of the composite, procedural complications, and technical parameters. Pooled odds ratios (ORs), risk ratios (RRs), and mean differences (MDs) with 95% confidence intervals (CIs) were calculated using RevMan software. Results: Seven observational studies were included, comprising patients treated with Watchman FLX (n=28,460; mean age 76.1 years; 40.5% female) and Watchman 2.5 (n=29,028; mean age 76.1 years; 40.5% female). Watchman FLX was associated with significantly higher odds of implantation success (OR 1.47, 95% CI 1.33–1.63, p <0.00001) and lower risk of major complications (RR 0.56, 95% CI 0.49–0.63, p <0.00001). Major bleeding, device embolism, and peridevice leak were significantly reduced in the Watchman FLX group. Additionally, Watchman FLX was associated with lower contrast volume (MD –10.48 mL, 95% CI –19.37 to –1.60, p =0.02) and radiation dose (MD –16.41 gray-centimeter squared, 95% CI –27.62 to –5.19, p =0.004). No significant differences were observed for death, stroke, or device-related thrombosis. Conclusions: Watchman FLX demonstrates higher implantation success and a significantly lower risk of major complications compared to Watchman 2.5. These findings support its increasing use in contemporary clinical practice.