Duration of anticoagulant application Anticoagulation for 3-6 months after bioprosthetic valve replacement; if atrial fibrillation is present, the duration of anticoagulation may be prolonged if there is a large left atrium. Lifetime anticoagulation after mechanical valve replacement Criteria for anticoagulation therapy and monitoring Insufficient amount of anticoagulants may cause the risk of thrombosis and embolism; overdose of anticoagulants may cause the risk of bleeding; therefore, correct anticoagulation is very important, and insufficient or excessive anticoagulation can threaten your health and life! Dong Nianguo, Department of Cardiac Surgery, Wuhan Union Medical College Hospital Normal values of coagulation function: prothrombin time (PT) 12-14 seconds; activity (PI) above 80%. After anticoagulation therapy, the appropriate standard is a PT of 1.5-2 times the normal value (21-28 seconds); activity between 35- 50%. The international ratio (INR) is also commonly used to evaluate the effect of anticoagulation, and the appropriate INR should be between 1.8 and 2.5. The normal INR value is 0.8-1.2. The target INR value varies among patients after valve replacement. The tricuspid valve has the highest anticoagulation requirements, followed by the mitral valve and then the aortic valve. The target INR for aortic valve replacement alone (mechanical valve) is 1.8-2.0; for mitral valve replacement alone (mechanical valve), the target INR is 2.0-2.5, and for tricuspid valve replacement alone (mechanical valve), the target INR is 2.5-3.0. For either valve replacement, the target INR is 1.5-2.0 as long as the valve is replaced with a biologic valve. To properly anticoagulate, it is important to frequently Blood should be collected frequently for laboratory testing to adjust the dose of medication. During the period of finding the appropriate dose (i.e., during the period of finding the dosing pattern), blood tests are usually performed once daily or every other day, and once a week after the pattern is found.