[Combined aortic and mitral valve replacement with or without preservation of posterior mitral apparatus]

Seventy patients who underwent aortic and mitral valve replacement were reviewed. 37 patients had the mitral valve replaced with preservation of posterior mitral apparatus (AVR and modified MVR; modified group), and the others without (AVR and conventional MVR; conventional group). Hospital deaths occurred in 4 patients (12.1%) in conventional group and in only 1 patient (2.7%) in modified group. Four out of these five hospital deaths were due to low output syndrome (LOS). The other one died of unknown cause. Severe LOS, necessitating intra-aortic balloon pumping, occurred in 4 (12.1%) in conventional group and in 2 (5.4%) in modified group. In the early postoperative period modified group showed better left ventricular function than conventional group in terms of cardiac index and left ventricular stroke work index. Cardiac performance was evaluated by means of echocardiography at the time of discharge. Modified group showed better fractional shortening and shorter PEP/ET (pre-ejection period/ejection time). These findings suggest that the lower mortality of modified group is due to better left ventricular function preventing LOS in the early postoperative period, and that preserving the posterior mitral apparatus has a more beneficial effect on postoperative left ventricular function even in combined valve disease.