Effect of concomitant antiplatelet agents on clinical outcomes in the edoxaban vs warfarin in subjects undergoing cardioversion of atrial fibrillation (ENSURE-AF) randomized trial

Aims In ENSURE-AF (NCT02072434), the oral Factor Xa inhibitor edoxaban showed similar efficacy and safety vs enoxaparin-warfarin in patients undergoing electrical cardioversion of nonvalvular atrial fibrillation (AF). This ancillary analysis compares primary efficacy and safety end points for patients receiving vs not receiving concomitant antiplatelet therapy (APT) in ENSURE-AF. Methods The primary efficacy end point was a composite of stroke, systemic embolic events, myocardial infarction, and cardiovascular death during 28 days on study drug after cardioversion plus 30 days of follow-up. The primary safety end point was the composite of major and clinically relevant non-major bleeding occurring between the first and the last dose of study drug. Results Of 2199 patients enrolled, 1095 were randomized to edoxaban and 1104 to enoxaparin-warfarin. Patients receiving concomitant APT were older; more naive to vitamin K antagonist; had lower creatinine clearance; and more likely to have history of coronary artery disease, hypertension, diabetes, or ischemic stroke/transient ischemic attack. In patients receiving vs not receiving concomitant APT, primary efficacy event rate was numerically higher (0.92% vs 0.60%, p = 0.64) and primary safety event rate was significantly higher (3.21% vs 0.92%, p = 0.0096). Stepwise logistic regression analysis identified age and APT as covariates correlated with bleeding. There was a trend toward increased bleeding risk in elderly patients receiving vs not receiving concomitant APT. Conclusion In ENSURE-AF, thromboembolic events were rare and absolute bleeding event rates were higher with concomitant APT. These findings may be relevant for AF-patients considered for dual therapy; even for a short treatment duration of 1 month.