Early Anticoagulation of Bioprosthetic Aortic Valves in Older Patients

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.