Comparing warfarin to aspirin (WoA) after aortic valve replacement with the St. Jude Medical Epic heart valve bioprosthesis: results of the WoA Epic pilot trial.

Patients with bioprosthetic heart valves have a higher risk of developing peripheral arterial embolic phenomena than the normal population. Antithrombotic therapy during the early postoperative period after bioprosthetic aortic valve replacement (BAVR) is controversial. This prospective pilot study sought to investigate the feasibility of a larger trial and the efficacy of postoperative warfarin compared to acetyl salicylic acid (aspirin; ASA) in patients after AVR with the St. Jude Epic porcine bioprosthesis (SJEP), and the feasibility of conducting a larger trial. METHODS: Patients undergoing isolated BAVR were allocated at random to two groups, each of which received different antithrombotic therapies: (i) warfarin (INR; range 2-3) for the first three months, followed by ASA (100 mg/day); or (ii) ASA alone (100 mg/day). RESULTS: During 2003 and 2004, a total of 75 patients underwent isolated BAVR with the SJEP. Six patients who developed postoperative de-novo atrial fibrillation that did not revert to sinus rhythm were excluded from the analysis, but included in the follow up. One postoperative cerebral ischemic event occurred in each group between 24 h and three months (2.8% versus 2.9%, p = NS). The rates of major bleeding, stroke-free survival and overall survival were similar in both groups. CONCLUSION: The early results of this WoA Epic pilot trial did not support the suggestion that patients receiving the SJEP, and tissue valves in general, should be administered warfarin to prevent valve thrombosis and peripheral arterial embolic phenomena.