Safety of Percutaneous Left Atrial Appendage Closure: Results From the Watchman Left Atrial Appendage System for Embolic Protection in Patients With AF (PROTECT AF) Clinical Trial and the Continued Access Registry

Study Questions:

What is the influence of experience on the safety of percutaneous left atrial appendage closure?


The study cohort for this analysis included patients in the PROTECT AF trial who underwent attempted device left atrial appendage closure (n = 542 patients) and those from a subsequent nonrandomized registry of patients undergoing Watchman implantation (Continued Access Protocol [CAP] Registry; n = 460 patients). The safety endpoint included bleeding- and procedure-related events (pericardial effusion, stroke, and device embolization).


There was a significant decline in the rate of procedure- or device-related safety events within 7 days of the procedure across the two studies, with 7.7% and 3.7% of patients, respectively, experiencing events (p = 0.007), and between the first and second halves of PROTECT AF and CAP, with 10.0%, 5.5%, and 3.7% of patients, respectively, experiencing events (p = 0.006). The rate of serious pericardial effusion within 7 days of implantation, which had made up >50% of the safety events in the PROTECT AF trial, was lower in the CAP Registry (5.0% vs. 2.2%, respectively; p = 0.019). There was a similar experience-related improvement in procedure-related stroke (0.9% vs. 0%, respectively; p = 0.039). Finally, the functional impact of these safety events, as defined by significant disability or death, was statistically superior in the Watchman group compared with the warfarin group in PROTECT AF. This remained true whether significance was defined as a change in the modified Rankin score of ≥1, ≥2, or ≥3 (1.8 vs. 4.3 events per 100 patient-years; relative risk, 0.43; 95% confidence interval, 0.24-0.82; 1.5 vs. 3.7 events per 100 patient-years; relative risk, 0.41; 95% confidence interval, 0.22-0.82; and 1.4 vs. 3.3 events per 100 patient-years; relative risk, 0.43; 95% confidence interval, 0.22-0.88, respectively).


The authors concluded that there is a significant improvement in the safety of Watchman left atrial appendage closure with increased operator experience.


This study suggests that the safety events in the Watchman group are largely procedure-related events, that these safety events decrease in frequency with greater operator experience, and that regardless of the definition used for significant disability, the rates of events resulting in significant disability or death were statistically lower for the Watchman device compared with warfarin therapy in the PROTECT AF trial. Although these data suggest a favorable safety profile for Watchman implantation, additional real-world safety data are needed. Furthermore, the availability of newer oral antithrombotics with a better safety profile may alter the risk/benefit ratio of these devices.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Pericardial Disease, Anticoagulation Management and Atrial Fibrillation, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Odds Ratio, Risk, Registries, Stroke, Atrial Appendage, Warfarin, Atrial Fibrillation, Risk Assessment, Pericardial Effusion

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