Under normal circumstances, blood can circulate smoothly and quickly in the heart vessels without forming clots. However, if there is a break in the heart or in the endothelium of a blood vessel or a foreign body (such as a heart prosthetic valve or a shaped ring), some components of the blood can adhere and collect, forming a clot. Therefore, strict anticoagulation therapy after surgery is very important. To prevent thrombosis, we need to take warfarin anticoagulation therapy. Oral warfarin anticoagulation is started on the first day after valve replacement and is taken at a relatively regular time of the day, usually around 3:00 pm in the hospital. You can also choose your own time after discharge from the hospital (usually in the afternoon, after the blood test results are available) and take it regularly. During the anticoagulation period, blood tests are required to monitor the prothrombin time (PT) and its international normalized ratio (INR). The current recommended values in most hospitals in China: INR control at 1.8-2.5 after mechanical valve, bioprosthetic valve replacement and prosthetic ring implantation. time required for anticoagulation: lifetime anticoagulation with warfarin for mechanical valves; 3-6 months with warfarin for prosthetic ring implantation; 3-6 months with warfarin for bioprosthetic valves. Post-discharge anticoagulation adjustment method: If the INR value is lower than the minimum of the range (1.8), warfarin dosage needs to be increased; if the INR value is higher than the maximum of the range (2.5), warfarin dosage needs to be reduced; if the INR value is greater than 3.0, the chance of bleeding increases, warfarin needs to be stopped on the same day, blood tests will be drawn the next day and readjusted according to the INR. Each time the amount of warfarin needs to be increased or decreased by 0.5-1 mg, i.e., 1/5-2/5 tablet,or 1/4-1/2 tablet. After discharge from the hospital, anticoagulation should be checked every 1-2 days. After 3-4 times, if the INR is stable, the interval between tests can be extended to 2 times a week. If the INR value is still stable, the interval between tests can be extended to once a week, once every 2 weeks, and finally once a month. Note: The test should be repeated at least once a month. The above “stable” means that the INR results are in the ideal range for 3 – 4 consecutive tests, and there is no need to increase or decrease the warfarin dose before extending the interval between blood tests. If you forget to take your warfarin today, just take the missed warfarin the next day along with your regular dose for that day. Of course, if you forget to take it for several days, then you must start taking it again. In addition to increasing the warfarin dose for the first few days as appropriate, the most important thing is to review the INR immediately and daily for the next few days until the INR reaches the appropriate range.