Left atrial appendage closure fails noninferiority test versus medical therapy in high-risk AF patients

BACKGROUND: Catheter-based closure of the left atrial appendage is an alternative to oral anticoagulation for stroke prevention in patients with atrial fibrillation. The effectiveness of this strategy, as compared with physician-directed best medical care, in patients at high risk for stroke and bleeding is unknown. METHODS: In this multicenter randomized trial conducted in Germany, we assigned patients with atrial fibrillation and a high risk of stroke and bleeding to undergo left atrial appendage closure or to receive physician-directed best medical care (including direct oral anticoagulants, if eligible). The primary end point, tested for noninferiority, was a composite of stroke (ischemic or hemorrhagic), systemic embolism, major bleeding, or cardiovascular or unexplained death, assessed in a time-to-event analysis. The noninferiority margin was a hazard ratio of 1.3. RESULTS: A total of 912 adult patients underwent randomization. The primary end-point analysis included 446 patients who were assigned to undergo left atrial appendage closure (device group) and 442 who were assigned to physician-directed best medical care (medical-therapy group). The mean (±SD) age was 77.9±7.1 years; 38.6% of the patients were women, the mean CHADS-VASc score was 5.2±1.5 (range, 0 to 9, with higher scores indicating a greater risk of stroke), and the mean HAS-BLED score was 3.0±0.9 (range, 0 to 9, with higher scores indicating higher risk of bleeding). After a median follow-up of 3 years (interquartile range, 1.7 to 4.7), a first primary end-point event had occurred in 155 patients (incidence per 100 patient-years, 16.8) in the device group and in 127 patients (incidence per 100 patient-years, 13.3) in the medical-therapy group (difference in restricted mean survival time, -0.36 years; 95% confidence interval, -0.70 to -0.01; P = 0.44 for noninferiority). Serious adverse events occurred in 368 patients (82.5%) in the device group and 342 (77.4%) in the medical-therapy group. CONCLUSIONS: Among patients with atrial fibrillation at high risk for stroke and bleeding, left atrial appendage closure was not noninferior to physician-directed best medical care with regard to a composite end point of stroke, systemic embolism, major bleeding, or cardiovascular or unexplained death. (Funded by the German Center for Cardiovascular Research; CLOSURE-AF ClinicalTrials.gov number, NCT03463317.).