in Mitral Valve Replacement

It is generally accepted that the mitral valve plays a role in left ventricular geometry and function. This is one of the reasons why the long-term outcome after mitral valve repair is usually better than after mitral valve replacement. However, mitral valve repair is difficult and sometimes not possible in patients with advanced pathologic changes in the leaflets and chordae tendineae, or in ischemic mitral regurgitation with undetermined physiopathology. In these cases, mitral valve replacement with chordal preservation provides better functional and more durable results than mitral valve repair. Unfortunately, with the exception of ischemic mitral regurgitation where the leaflets and chordae tendineae are often normal, most patients who need mitral valve replacement have grossly abnormal leaflets and chordae tendineae, which make their preservation hazardous and occasionally impossible. We believe that the native leaflet and chordae tendineae should be preserved during mitral valve replacement only in ischemic mitral regurgitation. Grossly abnormal chordae tendineae, such as those found in patients with advanced myxomatous disease of the mitral valve or with advanced rheumatic heart disease should be completely excised, and both papillary muscles should be resuspended with expanded polytetrafluoroethylene sutures. 1 In patients with ischemic mitral regurgitation, the mitral valve leaflets and chordae tendineae are fairly normal, and if repair is not feasible, most of the anterior leaflet is excised. This is accomplished by making an incision at the base of the anterior leaflet, at least 1 cm from the aortic valve, and extending it laterally and medially to approximately 5 mm from the commissures; then it is extended to the free margins of the anterior leaflet, leaving the commissural chordae intact. Two or more primary chordae tendineae attached to the central portion of the anterior leaflet are excised. The remnants of the anterior leaflet are incorporated into the sutures used to secure the mitral valve prosthesis.