1, the structure and function of the heart valves The heart is the blood pump of the human body and consists of four elastic cavities: the right atrium, the right ventricle, the left atrium and the left ventricle. The right atrium is connected to the right ventricle through the tricuspid valve, and the right ventricle is connected to the pulmonary artery through the pulmonary valve; the left atrium is connected to the left ventricle through the mitral valve, and the left ventricle is connected to the aorta through the aortic valve. Blood flows in the direction of right atrium → right ventricle → pulmonary artery (pulmonary circulation) → left atrium → left ventricle → aorta (body circulation) in one direction, in which the heart valve plays the role of “one-way valve”, so the valve is a very important structure in the heart. A normal heart valve can pass sufficient blood flow when it is open, and prevent blood from flowing back when it is closed. Due to congenital or acquired causes, the heart valves lose their normal anatomical structure and physiological function, and when they open, blood flow is blocked, i.e., heart valve stenosis; when they close, blood flows back, i.e., heart valve insufficiency; sometimes the same valve has both stenosis and insufficiency. When more than two valves are involved at the same time, it is called joint valve disease. 2, classification of heart valve disease Heart valve disease refers to heart function damage caused by anatomical and/or functional changes in the heart valves. They can be divided into two categories: congenital and acquired, and the latter can be divided into rheumatic and non-rheumatic heart valve diseases. Congenital heart valve malformations are primarily the result of disorders that occur during embryonic development (especially in the first trimester of pregnancy). Rheumatic heart valve disease is the result of rheumatic disease involving the heart valves and recurrent attacks, which develop over a long period of time. Rheumatic heart disease accounts for the first place of heart valve disease in our population, with more women than men. Acquired non-rheumatic heart disease includes age-related heart valve degenerative disease, traumatic heart valve damage, infective endocarditis, heart valve insufficiency caused by coronary heart disease and heart valve lesions caused by valvular mucus-like degeneration. 3, the specificity of valve patients of different ages Childhood valve disease: most of them are dominated by mitral valve closure insufficiency and severe hemodynamic changes leading to heart failure episodes. Children have fewer complications after valve replacement and early survival rates are no different from adults, but given the special problems of valve replacement in children, clinicians agree on the following two points: (1) there is no ideal replacement for children’s heart valves, and it is difficult to avoid re-replacement of small-sized valves as they develop and grow; (2) there are many variables after valve replacement that are different from those in adults, such as valve selection, post-anticoagulation bleeding complications, embolism, rheumatic activity, and reoperation . Therefore, the selection of indications for valve replacement in children is more stringent, and in principle, valve lesions are repaired using prosthetic methods whenever possible. Geriatric valve disease: Elderly patients with rheumatic heart disease are often combined with other diseases, such as coronary heart disease, diabetes mellitus, hypertension, pulmonary and renal insufficiency. This is an important factor affecting the outcome of the procedure. It is preferable to choose a bioprosthetic valve, which is durable enough to meet the natural lifespan. Therefore, the selection of indications for valve replacement in the elderly is focused on the basic clarification of the etiology and combined diseases through various examinations; the purpose of surgery is to prolong the life span of the patient and to improve the quality of life, and whether this standard can be achieved, the surgical indications must be considered.