Mitral valve replacement to treat heart valve disease without surgery are divided into three categories: Clinical Practice treatment (this is used in every day clinical practice), Investigational treatment (current clinical studies that are underway), Early Development treatment (early stages of investigation). People having mitral valve surgery receive general anesthesia. Incision can be made somewhat horizontally under the left breast, or vertically through the sternum. After the heart is exposed, canulae are placed to reroute blood to a heart-lung machine for cardiopulmonary bypass. An incision is made in the left atrium to expose the mitral valve. The valve is then replaced with either a
Mitral valve prolapse "atrialis", "fibrosa", and "spongiosa". Patients with classic mitral valve prolapse have excess connective tissue that thickens the spongiosa and separates collagen bundles in the fibrosa. This is due to an excess of dermatan sulfate, a glycosaminoglycan. This weakens the leaflets and adjacent tissue, resulting in increased leaflet area and elongation of the chordae tendineae. Elongation of the chordae tendineae often causes rupture, commonly to the chordae attached to the posterior leaflet. Advanced lesions—also commonly involving the posterior leaflet—lead to leaflet folding, inversion, and displacement toward the left atrium. Echocardiography is the most useful method of diagnosing a prolapsed mitral valve.