Open-Label Randomized Trial Comparing Oral Anticoagulation With and Without Single Antiplatelet Therapy in Patients With Atrial Fibrillation and Stable Coronary Artery Disease Beyond 1 Year After Coronary Stent Implantation: OAC-ALONE Study

Background: Despite recommendations in the guidelines and consensus documents, there has been no randomized controlled trial evaluating oral anticoagulation (OAC) alone without antiplatelet therapy (APT) in patients with atrial fibrillation and stable coronary artery disease beyond 1 year after coronary stenting. Methods: This study was a prospective, multicenter, open-label, noninferiority trial comparing OAC alone to combined OAC and single APT among patients with atrial fibrillation beyond 1 year after stenting in a 1:1 randomization fashion. The primary end point was a composite of all-cause death, myocardial infarction, stroke, or systemic embolism. The major secondary end point was a composite of the primary end point or major bleeding according to the International Society on Thrombosis and Haemostasis classification. Although the trial was designed to enroll 2000 patients during 12 months, enrollment was prematurely terminated after enrolling 696 patients in 38 months. Results: Mean age was 75.07.6 years, and 85.2% of patients were men. OAC was warfarin in 75.2% and direct oral anticoagulants in 24.8% of patients. The mean CHADS(2) score was 2.51.2. During a median follow-up interval of 2.5 years, the primary end point occurred in 54 patients (15.7%) in the OAC-alone group and in 47 patients (13.6%) in the combined OAC and APT group (hazard ratio, 1.16; 95% CI, 0.79-1.72; P=0.20 for noninferiority, P=0.45 for superiority). The major secondary end point occurred in 67 patients (19.5%) in the OAC-alone group and in 67 patients (19.4%) in the combined OAC and APT group (hazard ratio, 0.99; 95% CI, 0.71-1.39; P=0.016 for noninferiority, P=0.96 for superiority). Myocardial infarction occurred in 8 (2.3%) and 4 (1.2%) patients, whereas stroke or systemic embolism occurred in 13 (3.8%) and 19 (5.5%) patients, respectively. Major bleeding occurred in 27 (7.8%) and 36 (10.4%) patients, respectively. Conclusions: This randomized trial did not establish noninferiority of OAC alone to combined OAC and APT in patients with atrial fibrillation and stable coronary artery disease beyond 1 year after stenting. Because patient enrollment was prematurely terminated, the study was underpowered and inconclusive. Future larger studies are required to establish the optimal antithrombotic regimen in this population. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01962545.