DETERMINANTS OF SURVIVAL AND LEFT-VENTRICULAR PERFORMANCE AFTER MITRAL-VALVE REPLACEMENT

To determine how survival and clinical status were related to left ventricular (LV) size and systolic function after mitral valve replacement, 104 patients (48 mitral regurgitation [MR], 33 mitral stenosis [MS], and 23 MS/MR) with isolated mitral valve replacement were evaluated before and after surgery. Preoperative hemodynamic abnormalities by cardiac catheterization were improved 6 months after surgery in all three patient groups. The patients with MR exhibited reductions in LV end-diastolic volume index (EDVI) (117 ± 51 to 89 ± 27 ml/m2, p < 0.001) and ejection fraction (EF) (0.56 ± 0.15 to 0.45 ± 0.13, p < 0.001); however, the ratio of forward stroke volume to end-diastolic volume increased (0.32 ± 0.21 to 0.45 ± 0.17, p < 0.001) because of the elimination of regurgitant volume. Survival analysis revealed that mortality was significantly higher in MS or MS/MR patients with postoperative EDVI more than 101 ml/m2 (p < 0.001 and p < 0.042, respectively) and in MR patients with postoperative EF less than or equal to 0.50 (p < 0.031). Also, the majority of patients with MR or MS/MR and postoperative EDVI more than 101 ml/m2 and EF less than or equal to 0.50 were in New York Heart Association class III or IV. Multivariate logistic regression analysis in the patients with MR revealed that the strongest predictor of postoperative EF was preoperative EF (p < 0.001). Preoperative mean pulmonary artery pressure less than or equal to 20 mm Hg was a significant determinant of postoperative EDVI less than or equal to 101 ml/m2 in patients with MR (p < 0.03). The most significant predictor of persistent LV enlargement in patients with MR or MS/MR was a large end-systolic volume index (ESVI) before operation (p < 0.002). Therefore, surgery should be considered in MR or MS/MR patients before EF decreases to less than 0.50, ESVI is more than 50 ml/m2, or pulmonary hypertension develops.