Clinical question: Is mechanical, left atrial appendage (LAA) closure as effective as warfarin therapy in preventing cardioembolic events in patients with nonvalvular atrial fibrillation (Afib)?
Background: Anticoagulation with warfarin has long been the standard therapy for prevention of thromboembolic complications of nonvalvular Afib; however, its use is limited by the need for monitoring and lifelong adherence, as well as its many dietary and medication interactions. Prior studies investigating the efficacy of a deployable device intended to close the LAA have shown noninferiority of the device when compared with standard warfarin anticoagulation. This study evaluated LAA closure device efficacy after a 3.8-year interval.
Study design: Randomized, unblinded controlled trial.
Setting: Fifty-nine centers in the U.S. and Europe.
Synopsis: Authors randomized 707 participants 18 years or older with nonvalvular Afib and CHADS2 score ≥1 in a 2:1 fashion to the intervention and warfarin therapy groups. The primary outcome was a composite endpoint including stroke, systemic embolism, and cardiovascular or unexplained death. The event rate in the device group was 2.3 per 100 patient-years, compared with 3.8 in the warfarin group. Rate ratio was 0.60, meeting noninferiority criteria. Primary safety events were not statistically different.
Although the authors concluded that LAA device closure was noninferior to warfarin therapy, it should be noted that there was a high dropout rate, especially in the warfarin group, motivated either by a desire to try a novel oral anticoagulant or the perception that warfarin therapy was not beneficial. It should also be noted that device placement involved not only a percutaneous procedure, but also 45 days of aspirin and warfarin therapy initially to promote endothelization, followed by six months of clopidogrel.
Bottom line: Percutaneous device closure of the LAA appears to be noninferior to warfarin therapy in the prevention of cardioembolic events over a period of several years, and might be superior.
