There are two general types of valves commonly used in valve replacement today: mechanical and biologic valves. The mechanical valve is composed of a fabric sutured edge + metal ring + pyrolyzed carbon leaflet. The disadvantage is that it requires a lifetime of anticoagulant medication, which varies from person to person and requires periodic blood coagulation tests to determine the coagulation index (generally 3 months to half a year after PT stabilization), which is relatively cumbersome. The price of anticoagulants is not high, and the daily price of domestic drugs is less than 0.5 yuan. The mechanical flap is divided into imported and domestic flaps, with imported flaps costing 15,000 yuan and domestic flaps costing 0.5 million yuan. The aortic valve is generally more important to replace the imported valve, and the mitral valve is best replaced with an imported valve when available, but domestic valves can also be used. The commonly used biological valve is a fabric sutured edge + fabric-wrapped frame + a leaflet made of xenobiotic tissue (a heart valve from a pig or a leaflet made from a bovine pericardium). This valve is characterized by the absence of anticoagulation, with the disadvantage of the possibility of valve failure, especially in relatively young patients. According to foreign experience, when used with good results in patients over 65 years of age, approximately 90% of valves function well after 15 years. Therefore, in current clinical work, bioprosthetic valves are generally used again in patients in their sixties. For special cases, such as women who need to give birth (usually multiple births abroad!) , or patients who are not suitable for anticoagulation, they can also be used!