[PT-INR as a parameter for anticoagulant therapy after valve replacement surgery]

We retrospectively analyzed the intensity of anticoagulant therapy in the 195 patients who underwent valve replacement surgery with mechanical valves. An optimal level or target range of prothrombin time-international normalized ratio (PT-INR) was sought. Previously, we employed a range of 10 to 25% of thrombotest value, which corresponded to the range of 1.5 to 3.5 of PT-INR value. In one patient who underwent mitral valve replacement, PT-INR valve was 1.72 when he developed an episode of cerebral thromboembolism. There was no tendency in PT-INR value in 51 patients who developed non-critical bleeding. As a while, PT-INR value was over 4.0 in 2 patients who required a in-hospital treatment for major bleeding complications. Based on our experience, we recommend a range of 2.0 to 3.0 of PT-INR value after valve replacement surgery with mechanical valves.