Safety of Left Atrial Appendage Closure With WATCHMAN Device
What are the procedural success and complications, and long-term patient outcomes, including bleeding and incidence of stroke/transient ischemic attack (TIA), with the WATCHMAN device?
Briefly, EWOLUTION was designed as a multicenter, prospective, nonrandomized cohort study aiming to include over 1,000 patients. Subjects were recruited from the general population of clinical sites at each participating physician’s discretion if they were eligible to receive the WATCHMAN device according to the appropriate local and international guidelines. Baseline/implant data were available for 1,021 subjects. Rates of events were calculated via the Kaplan–Meier method to account for censoring. P values were based on log-rank tests for time-to-event analysis and Fisher’s exact test for binomial proportions.
Subjects in the study were at high risk of stroke (average CHADS2 score: 2.8 ± 1.3, CHA2DS2-VASc: 4.5 ± 1.6) and moderate-to-high risk of bleeding (average HAS-BLED score: 2.3 ± 1.2). Almost one-half of the subjects (45.4%) had a history of TIA, ischemic stroke, or hemorrhagic stroke; 62% of patients were deemed unsuitable for a novel oral anticoagulant by their physician. The device was successfully deployed in 98.5% of patients, with no flow or minimal residual flow achieved in 99.3% of implanted patients. Twenty-eight subjects experienced 31 serious adverse events (SAEs) within 1 day of the procedure. The overall 30-day mortality rate was 0.7%. The most common SAE occurring within 30 days of the procedure was major bleeding requiring transfusion. Incidence of SAEs within 30 days was significantly lower for subjects deemed to be ineligible for oral anticoagulation therapy (OAT) compared with those eligible for OAT (6.5 vs. 10.2%, p = 0.042).
The authors concluded that left atrial appendage closure (LAAC) with the WATCHMAN device has a high success rate in complete LAAC with low periprocedural risk.
This study reports that LAAC can be successfully and relatively safely performed in an even wider variety of patients, both in terms of the greater variation of clinical settings than was seen in past clinical trials and in terms of a higher proportion of patients deemed unsuitable for OAT. These data suggest that improvement in implantation techniques has led to a consistent reduction of periprocedural complications that were previously limiting the net clinical benefit of the procedure. It should be noted, however, that although EWOLUTION was set up as a prospective registry with clear prespecified data collection, the study methods are not equal to those in randomized clinical trials, which may limit a direct comparison of outcome.
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