Anticoagulation after valve replacement: a multicenter retrospective study.

Anticoagulant therapy after cardiac valve replacement was evaluated retrospectively in 1,200 patients attending 8 cardiac surgery clinics in the Tokyo area as part of the Tokyo Area Study on Anticoagulation After Cardiac Valve Replacement Using PT-INR (TAS). A prospective trial is also in progress and will be reported later. The prothrombin time international normalized ratio (PT-INR) was determined at the time of thromboembolic and bleeding complications in 1,200 patients. During the 5 year study period, thromboembolisms occurred in 21 patients, and bleeding complications occurred in 15 patients. In 71% of patients with thromboembolism and 47% of those with bleeding complications, the PT-INR was within the range of 1.6 to 2.8, which is the accepted therapeutic range in Japan. Therefore, the correct PT-INR therapeutic range for Japanese patients with mechanical heart valves needs to be reexamined, and data from the prospective TAS trial that is currently underway will be used for this purpose.