Low-dose acetyl salicylic acid versus oral anticoagulation after bioprosthetic aortic valve replacement. Final report of the ACTION registry.

BACKGROUND: The administration of antiplatelet agents versus anticoagulation after bioprosthetic aortic valve replacement (AVR) remains controversial. This study examined the safety and efficacy of anticoagulation with a vitamin-K antagonist (VKA) versus low-dose acetyl salicylic acid (ASA), up to 6 months after bioprosthetic AVR. METHODS: The ACTION Registry prospectively collected data at 47 medical centers in Europe, Canada and India. The investigators were free to prescribe the postoperative antithrombotic regimen of their choice. Between January 2006 and June 2009, 1118 patients underwent AVR alone or combined with coronary artery bypass graft (CABG), of whom 500 received a VKA and 618 received ASA. RESULTS: Patients who received VKA had a higher prevalence of peripheral vascular disease, chronic renal insufficiency and coronary artery disease. At 180 days, 14 anticoagulated patients (2.8%) suffered a thromboembolism (TE) versus 9 patients (1.5%) treated with ASA (P=0.12) and 18 anticoagulated patients (3.6%) suffered major bleeding (MB) versus 8 patients (1.3%) in the ASA group (P=0.01). MB or TE occurred in 31 patients (6%) treated with VKA versus 17 patients (2.8%) treated with ASA (P=0.003). By multiple variable analysis, preoperative cerebrovascular accident and peripheral vascular disease were strong predictors of postoperative TE, MB or both, in patients treated with VKA, though not in patients treated with ASA. CONCLUSIONS: Compared with ASA, treatment with VKA was associated with higher morbidity within 6 months after bioprosthetic AVR, suggesting that, particularly after concomitant CABG surgery, recipients of bioprosthetic AVR should receive prophylactic ASA instead of VKA.