Randomized On-X Anticoagulation Trial

This is a longitudinal, randomized (randomization to occur at the 3-month follow-up) study comparing the On-X valve on low dose anticoagulation (test group) to concomitant control groups of On-X valves receiving standard Coumadin/aspirin therapy, and also to FDA objective performance criteria (OPC) for heart valve replacement. It is a multicenter study consisting of up to 50 centers in the United States, Canada, and Italy enrolling and randomizing no more than 1200 patients (200 in each of 6 groups). There are three test arms of the study: low risk aortic valve replacement, high risk aortic valve replacement, and mitral valve replacement. Each arm has an equivalent control. Test therapies are: low risk aortic valve replacement - aspirin/Plavix, high risk aortic valve replacement - Coumadin at INR of 1.5 to 2.0 plus aspirin, and mitral valve replacement - Coumadin at an INR of 2.0 to 2.5 plus aspirin. Follow-up will run for up to 8 years in each patient. Each arm is independent and the low risk aortic and high risk aortic arms are completed. The low risk aortic arm was closed early resulting in a reduction of the estimated total enrollment with randomization to 1000. The high risk arm is completed with FDA review and this arm had 375 randomized enrollees. The mitral arm continues to enroll with a planned randomized enrollment of 400.