1. Lifetime oral warfarin (3 mg per tablet, blue color, made in Finland) for mechanical valve replacement; six months oral warfarin for biological valve replacement by Chongjian Li, Department of Cardiovascular Medicine, Fu Wai Hospital, Beijing. 2. The international standard ratio (INR) or prothrombin activity was obtained by blood sampling and laboratory tests, and the oral dose of warfarin was adjusted according to the laboratory results of anticoagulation. The goal is to keep the dose between 1.8-2.2 When INR>2.2, reduce the oral dose of warfarin When INR<1.8< span="">, increase the oral dose of warfarin When INR>2.5, stop taking warfarin on the same day, go to the hospital for anticoagulation tests the next day, and decide the oral dose of warfarin according to the results The amount of each increase or decrease is usually 0.5-1 mg (1/6 tablet-1/3 tablet) 4. the timing of laboratory tests; gradually extend the interval of laboratory tests as follows: check the anticoagulation every other day after discharge, adjust the dose according to the above method, and extend the interval of laboratory tests when the INR is stable at 1.8-2.2. When the INR is stable at 1.8-2.2, the interval between tests can be extended. ———- Check anticoagulation twice a week, also adjust the dose according to the above method, and then extend the interval between tests when the INR is stable at 1.8-2.2. ———— Check once a week. ———- Stable ———– Check once every two weeks. ——— Stable —- —– checked once a month Stable means that three to four consecutive INR lab results are between 1.8-2.2 and no increase or decrease in the oral dose of warfarin is required 5. Each lab result and the oral dose of warfarin should be recorded in the table 6. If there are bleeding or coagulation complications after discharge from the hospital, visit the local hospital. A complete examination, including echocardiogram, chest radiograph and electrocardiogram, is done at 3 months of discharge.