The Value Of Preservation Of The Mitral Subvalvular Apparatus On Left Ventricular Function After Mitral Valve Replacement

Abstract

The papiJlary muscles play an important role in left ventricular contraction by drawing the mitral ring toward the apex, thereby causing shortening of the long axis and sphericity of the chamber for the ejection of blood (Rushmer et al, 1956). Conventional operative techniques for mitral valve replacement cut off the continuity between the mitral annulus and the papillary muscles. This results in postoperative decrease in left ventricular ejection fraction (Kennedy et al, 1979). In 1964 Lillehei and co-workers noted this continuity between the mitral ring and papillary muscles and devised an operative method of mitral valve replacement that preserved the posterior leaflet and its apparatus. The use of this method decreased operative mortality from 37 to 14%. However, the method was not widely used, presumably because the preserved chordae tendineae interfered with caged-ball valve motion (Lillehei et al, 1964). About twenty years later, Hetzer and associates revised the technique of Lillehei and associates with employment of a tissue valve as a substitute (Hetzer et al, 1983)

In 1981 David et al, concluded that preservation of the attachment between the left ventricular waH and mitral annulus bad a beneficial effect on cardiac performance when comparing conventional mitral valve replacement with mitral valve replacement with preservation of chordae tendinae and papillary muscles in dogs (David et a1, 1981).

In 1983 they started to apply the same technique of preservation when doing mitral valve replacement and they concluded that continuity between the mitral annulus and left ventricular wall through leaflets, chordae tendinae, and papillary muscles plays a role in left ventricular function after correction of chronic mitral regurgitation (David et al, 1983). Mild et al, started using the same method of preservation and expanded the procedure to preserve not only the posterior leaflet