Bileaflet versus posterior-leaflet-only preservation in mitral valve replacement.

In the present study of mitral valve replacement, we investigated whether complete preservation of both leaflets (that is, the subvalvular apparatus) is superior to preservation of the posterior leaflet alone. Seventy patients who underwent mitral valve replacement in our clinic were divided into 2 groups: MVR-B (n=16), in whom both leaflets were preserved, and MVR-P (n=54), in whom only the posterior leaflet was preserved. The preoperative and postoperative clinical and echocardiographic findings were evaluated retrospectively. No signs of left ventricular outflow tract obstruction were observed in either group. In the MVR-B group, no decrease was observed in left ventricular ejection fraction during the postoperative period, whereas a significant reduction was observed in the MVR-P group (P=0.003). No differences were found between the 2 groups in their need for inotropic agents or intra-aortic balloon pump support, or in cross-clamp time, duration of intensive care unit or hospital stays, postoperative development of new atrial fibrillation, or mortality rates. Bileaflet preservation prevented the decrease in left ventricular ejection fraction that usually followed preservation of the posterior leaflet alone. However, posterior leaflet preservation alone yielded excellent results in terms of decreased left ventricular diameter. Bileaflet preservation should be the method of choice to prevent further decreases in ejection fraction and to avoid death in patients who present with substantially impaired left ventricular function.