Mitral valve replacement

Mitral valve replacement is a procedure whereby the diseased mitral valve of a patient's heart is replaced by either a mechanical or tissue (bioprosthetic) valve. The mitral valve may need to be replaced because: The valve is leaky (mitral valve regurgitation) The valve is narrowed and doesn't open properly (mitral valve stenosis) Causes of mitral valve disease include infection, calcification and inherited collagen disease. Current mitral valve replacement approaches include open heart surgery and minimally invasive cardiac surgery (MICS). The mitral valve is a bileaflet valve sited between the left atrium and left ventricle, responsible for preventing blood flowing from the ventricle to the atrium when the heart contracts. It is elliptical, and its area varies from 5.0 to 11.4 cm2. The valve leaflets are separated by two commissures, and each leaflet of the valve (anterior leaflet, the large one, and posterior leaflet, the small one) has three sections (p1, p2, p3). Histologically, each leaflet is composed of the solid fibrosa, the spongiosa at the atrial surface and another fibroelastic layer covering the leaflets. Two papillary muscles originating from the base of the left ventricle hold the mitral leaflets in place through chordae tendinae, which insert the edge of the leaflets, preventing them from leaking during left ventricle systole. During normal mitral valve function fluid jets from the left atrium through the mitral valve into the left ventricle. The vortex created from this jetting travels towards the apex of the left ventricle because of the asymmetric shape of the mitral valve leaflets. This vortex rotates clockwise until the isovolumetric contraction of the left ventricle opens the aortic valve and redirects the fluid flow from the apex of the left ventricle to the systemic circulation and the rest of the body. It is important to emphasize that the asymmetry of the mitral valve is very important in the diastolic flow patterns of transmitral flow.