clinicaltrials.gov Identifier: NCT00129545.

These 5-year outcomes of the PREVAIL trial, combined with the 5-year outcomes of the PROTECT AF trial, demonstrate that LAAC with Watchman provides stroke prevention in nonvalvular atrial fibrillation comparable to warfarin, with additional reductions in major bleeding, particularly hemorrhagic stroke, and mortality. (WATCHMAN Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation; NCT00129545; and Evaluation of the WATCHMAN LAA Closure Device in Patients With Atrial Fibrillation Versus Long Term Warfarin Therapy; NCT01182441).

After left atrial appendage closure with Watchman, DRT (≈3.7%) is not frequent but, when present, is associated with a higher rate of stroke and systemic embolism.

Background: Left atrial appendage (LAA) occlusion provides an alternative to oral anticoagulation (OAC) for thromboembolic risk reduction in patients with non-valvular atrial fibrillation (NVAF). Since regulatory approval in 2015, the WATCHMAN device has been the only LAA closure device available for clinical use in the United States. The PINNACLE FLX study evaluated the safety and effectiveness of the next-generation WATCHMAN FLX LAA closure device in patients with NVAF in whom OAC is indicated, but who have an appropriate rationale to seek a non-pharmaceutical alternative. Methods: This was a prospective, non-randomized, multi-center FDA study. The primary safety endpoint was the occurrence of one of the following events within 7 days post-procedure or by hospital discharge, whichever was later: death, ischemic stroke, systemic embolism, or device- or procedure-related events requiring cardiac surgery. The primary effectiveness endpoint was the incidence of effective LAA closure (peri-device flow ≤5mm), as assessed by the echocardiography core laboratory at 12-month follow-up. Results: A total of 400 patients were enrolled. The mean age was 73.8{plus minus}8.6 years and the mean CHA2DS2-VASc score was 4.2{plus minus}1.5. The incidence of the primary safety endpoint was 0.5% with a one-sided 95% upper confidence interval (CI) of 1.6%, meeting the performance goal (PG) of 4.2% (P<0.0001). The incidence of the primary effectiveness endpoint was 100%, with a onesided 95% lower CI of 99.1%, again meeting the PG of 97.0% (P<0.0001). Device-related thrombus was reported in 7 patients, no patients experienced pericardial effusion requiring open cardiac surgery, and there were no device embolizations. Conclusions: LAA closure with this next generation LAA closure device was associated with a low incidence of adverse events and a high incidence of anatomic closure. Clinical Trial Registration: URL https://clinicaltrials.gov Unique Identifier NCT02702271

Despite a large fraction of previously inexperienced operators, in the real-world post-FDA approval experience of LAAC, procedural success was high and complication rates were low.