Early anticoagulation of bioprosthetic aortic valves in older patients: results from the Society of Thoracic Surgeons Adult Cardiac Surgery National Database.

OBJECTIVES The aim of this study was to evaluate the risks and benefits of short-term anticoagulation in patients receiving aortic valve bioprostheses. BACKGROUND Patients receiving aortic valve bioprostheses have an elevated early risk of thromboembolic events; however, the risks and benefits of short-term anticoagulation have been debated with limited evidence. METHODS Our cohort consisted of 25,656 patients ≥65 years of age receiving aortic valve bioprostheses at 797 hospitals within the Society of Thoracic Surgeons Adult Cardiac Surgery Database (2004 to 2006). The associated 3-month incidences of death or readmission for embolic (cerebrovascular accident, transient ischemic attack, and noncerebral arterial thromboembolism) or bleeding events were compared across discharge anticoagulation strategies with propensity methods. RESULTS In this cohort (median age, 77 years), the 3 most common discharge anticoagulation strategies included: aspirin-only (49%), warfarin-only (12%), and warfarin plus aspirin (23%). Among those receiving aspirin-only, 3-month adverse events were low (death, 3.0%; embolic events, 1.0%; bleeding events, 1.0%). Relative to aspirin-only, those treated with warfarin plus aspirin had a lower adjusted risk of death (relative risk [RR]: 0.80, 95% confidence interval [CI]: 0.66 to 0.96) and embolic event (RR: 0.52, 95% CI: 0.35 to 0.76) but a higher risk of bleeding (RR: 2.80, 95% CI: 2.18 to 3.60). Relative to aspirin-only, warfarin-only patients had a similar risk of death (RR: 1.01, 95% CI: 0.80 to 1.27), embolic events (RR: 0.95, 95% CI: 0.61 to 1.47), and bleeding (RR: 1.23, 95% CI: 0.85 to 1.79). These results were generally consistent across patient subgroups. CONCLUSIONS Death and embolic events were relatively rare in the first 3 months after bioprosthetic aortic valve replacement. Compared with aspirin-only, aspirin plus warfarin was associated with a reduced risk of death and embolic events, but at the cost of an increased bleeding risk.