Mitral valve repair versus replacement.

When considering all the major series comparing the early and late results of mitral valve repair versus prosthetic or bioprosthetic mitral valve replacement, the operative mortality rate is slightly lower for patients undergoing valve reconstruction. Late survival is also superior after valve repair. Although these modest differences may be related to patient selection bias, a lower rate of thromboembolic and endocarditis-related complications and improved LV function remain as rather compelling factors favoring valve repair. The durability of valve repair is comparable to valve replacement in terms of reoperation rate, except in cases of rheumatic valve abnormality (in which reoperation rates are higher after valvuloplasty). Definitive, objective evidence favoring mitral valve repair is lacking given the short period of followup in all studies and absence of controlled, randomized clinical trials. The success of mitral valve reconstruction relies heavily on the experience and technical expertise of the surgeon. The wide variability in observed survival rates, however, is unlikely to be due to differences in surgical skill between experienced groups; it more likely represents the results of differing criteria for mitral valve repair, various followup intervals, and comparisons between distinctly different cohorts. Although a prospective randomized trial would be ideal to compare the results of mitral valve reconstruction versus mitral valve replacement for patients with mitral valve regurgitation, it is unlikely and unrealistic that such a study will ever be conducted. The universal applicability of the results of such a study would also be dubious, given the widely varying extent of surgical expertise with mitral valve repair. Furthermore, not all types of mitral regurgitation are amendable to reconstruction short of using patch techniques (usually autologous pericardium treated with glutaraldehyde) or resorting to artificial chordae (e.g., extensive leaflet destruction from rheumatic changes or infective endocarditis, and substantial anterior leaflet redundancy). In cases in which mitral valve replacement is necessary, preservation of the mitral subvalvular apparatus promises to be an important concept to preserve optimal systolic LV function postoperatively.