Mitral stenosis is almost 100% the result of rheumatic lesions. In the early stages, edema and exudation occur at the intersection of the mitral valve and at the base of the valve, and later, due to fibrin deposition and fibrous degeneration, it is the valve edge that adheres and the valve thickens, calcifies, and fuses leading to stenosis of the valve. According to the degree of lesion and leaflet morphology, they can be divided into septal and funnel type. In mild lesions or early stages, the valve leaflet junction adhesions and thickened margins are the main cause of stenosis, but leaflet movement is not limited. As the lesion worsens, the leaflets thicken further, calcification and stiffness appear, the subvalvular tendon cords and papillary muscles shorten, thicken, fuse and stiffen, and the mitral valve morphology becomes funnel-shaped, called funnel type. Mitral valve insufficiency has both congenital and acquired lesions. The main congenital lesions are enlargement of the annulus, leaflet dehiscence and defect, and prolapse of the leaflet due to overgrowth of the tendon and papillary muscle. Acquired lesions are mainly rheumatic lesions, thickening and calcification of the valve leaflets, edge involution and sclerosis, which reduce the leaflet area and prevent the valve from closing, and thickening, shortening, insufficiency, and rupture of the tendon cords and papillary muscles due to various causes. The indications for mitral valvuloplasty include: 1) congenital mitral valve insufficiency, valve annulus enlargement, leaflet splitting, long tendon cords, or leaflet prolapse; mitral valve stenosis but leaflet area is not small. 2, rheumatic heart disease, mitral septum-like changes, hyperacusis of the first heart sound, no fusion shortening of the subvalvular tendon cords, no calcification of the valve, and good mobility. 3, degenerative valve degeneration, elongated tendon cords resulting in valve leaflet prolapse. 4, Mitral valve prolapse due to ischemic papillary muscle lesion, as a result of post-infarction papillary muscle fibrosis, lengthening or rupture. Risks of mitral valvuloplasty: Because of the intraoperative use of sutures and the possibility of thrombus formation in the early postoperative period with the prosthetic annulus, postoperative anticoagulation is recommended, starting the day after surgery and maintained for 4-6 weeks in sinus rhythm, and if atrial fibrillation is present, unless anticoagulation is contraindicated, otherwise warfarin anticoagulation should be continued. The incidence of thrombosis is: 0-5%, operative mortality is about 1-5%, and 90% of patients recover cardiac function to class I or II, but the chances of needing to undergo mitral valve surgery again increase significantly after 3-10 years.