1, we must know that lifelong anticoagulation therapy is required after mechanical valve replacement, which means taking warfarin; if there is no atrial fibrillation (referred to as: atrial fibrillation) after biological valve replacement, the patient needs anticoagulation therapy for 6 months; if there is atrial fibrillation, lifelong anticoagulation therapy is required. 2, the dosage of warfarin is recommended to start with a small dose, the general recommended dose is 3mg, and then adjust the dosage of warfarin according to the regular blood test anticoagulation check. 3, anticoagulation laboratory tests refer to the regular review of prothrombin time, prothrombin activity, international normalized ratio (INR). Since the results of the first two tests are not very stable, the adjustment of anticoagulants is mainly based on the International Normalized Ratio (INR). Wang Yue, Department of Cardiac and Macrovascular Surgery, Second Affiliated Hospital of Zhejiang University School of Medicine 4. The international normalized ratio (INR) in the general population is generally around 0.8-1.2; post-valve replacement patients need to increase the INR value to between 1.8-2.5 by taking warfarin. In the case of post-tricuspid valve replacement patients, INR values need to be maintained between 2.0 and 3.0. When INR is lower than 1.8, increase warfarin by 1/4 tablet on top of yesterday’s dosage; when INR is greater than 2.5, reduce warfarin by 1/4 tablet on top of yesterday’s dosage; when INR is greater than 3.0, stop the drug once on the same day and recheck the next day, then decide the dosage according to the examination results. 5. It takes 2-3 days for warfarin to take full effect, so the INR value checked on the same day reflects the efficacy of the oral warfarin taken 2-3 days ago. The INR needs to be reviewed frequently in the early days after discharge, and should be measured at least 3-4 times in the first week; it can be reduced to about 2-3 times in the second and third weeks; later, as the INR becomes stable, the number of measurements will be gradually reduced; even for patients with stable INR, it is recommended to review the INR once every 1-2 months. 6, warfarin needs to be taken once a day, and it is recommended that the time of taking the drug and the time of INR testing be relatively fixed.