There are two types of prosthetic valves: mechanical and biological: 1. Advantages of mechanical valves: mechanical valves are designed to last longer than biological valves, and a single valve replacement can basically last a lifetime. Disadvantages: A. Mechanical valves installed into the body, will grow thrombus, in order to prevent thrombosis, you need to take anticoagulants (warfarin) for life. Also, in order to adjust the dose of warfarin, it is necessary to regularly visit the hospital to take blood tests to monitor the anticoagulation index. This may affect the patient’s quality of life after surgery. b. Overdose of warfarin can lead to bleeding, and underdose of warfarin can lead to thrombosis. c. In a quiet environment Sometimes you may hear a “tick-tock” sound in the chest, which is normal for mechanical valves, but if you are very sensitive to noise and have insomnia, you should consider this when choosing a valve. Of course, the vast majority of patients can accept and adapt to this sound.D. Taking warfarin during pregnancy may lead to fetal malformation, and during pregnancy and delivery may lead to fetal, placental, and maternal hemorrhage, thus endangering the lives of mother and child, so women of childbearing age who are ready to replace their valves should consider this carefully, while men do not have this problem, which will be described in detail later. 2. The advantages of a biologic valve, as opposed to a mechanical valve, are that it does not require a lifetime of anticoagulant medication, but only 3-6 months, during which time only, regular blood tests are required, and if there is no atrial fibrillation, warfarin anticoagulation can be discontinued after 3-6 months, so the risk of thrombosis and bleeding associated with it is greatly reduced. The disadvantages are: poorer durability than mechanical valves, shorter service life than mechanical valves, and damage to the bioprosthetic valve over time. Therefore, if the bioprosthetic valve becomes damaged after several years of surgery, a second valve replacement surgery will be faced. In general, the younger the patient is, the faster the bioprosthetic valve will break down, the shorter the service life, and the greater the chance of a second surgery. How long does it last for each patient? It is impossible to give a definitive answer to this question because the life expectancy varies depending on the patient’s physical condition, metabolic status, exercise level, basal heart rate, blood pressure, etc. Therefore, when choosing a valve, you need to fully anticipate the possibility of a second surgery. The choice between mechanical and biologic valves has its own advantages and disadvantages and is based on the patient’s age, general condition, co-morbidities, as well as his or her own life, work, physical strength, psychological factors, economic conditions, and other practical considerations to see which one is suitable for him or her. In summary: in general, biological flaps are suitable for the following cases: 1. women of childbearing age who wish to become pregnant. This is because patients who have a mechanical flap exchange are at risk of fetal malformations, bleeding, and other problems from taking warfarin before and during pregnancy. This problem can be avoided if the biological valve is replaced. 2.In terms of age, a biological valve can be preferred for mitral valve replacement over 65 years old and aortic valve replacement over 60 years old. 3, Suffering from bleeding disorders or being a bleeding body themselves, they cannot take anticoagulants for a long time. 4.In distant mountain villages where long-term anticoagulation monitoring cannot be performed. 5, unwilling to use mechanical flaps, unwilling to run hospital blood tests frequently (even if it is once a month), requiring a higher quality of life. 6.Patients with poor general condition and physical fitness (life expectancy is not long).