Background: Volume overload secondary to mitral regurgitation (MR) in cardiomyopathy is considered critical in the pathogenesis of subsequent ventricular dysfunction. Open mitral valve repair (OMVP) is hypothesized to improve symptomatology and ventricular function by reducing the volume overload of the left ventricle.
Methods and results: All patients who underwent OMVP with a left ventricular ejection fraction (EF) of < 0.30 (n = 81) from 1984 through 1997 were reviewed (1 patient was lost to follow-up). Fifteen operations (18.5%) were repeat operations after previous coronary artery bypass graft surgery. Preoperative and postoperative EFs and NYHA class were compared. Survival probabilities were calculated, and multivariate analysis was performed. The average age of all patients was 67.1 years (range, 41 to 83 years). Mean follow-up was 1.7 years (range, 2 months to 8.5 years). The most common mitral repair was ring annuloplasty. Sixty-two patients (77%) had concomitant coronary artery bypass graft surgery. The surgery mortality rate was 11% (9 of 81); 6 of these 9 patients were > 70 years old. The overall Kaplan-Meier survival probability rate at 1, 2, 3, 4, and 5 years was 0.73, 0.68, 0.58, 0.50, and 0.38, respectively. EF improved significantly (0.24 to 0.32; P < 0.0001), as did the NYHA class (3.2 to 1.6; P < 0.0001), at follow-up. There was no difference in late survival between patients with an EF of < 0.20 (21 patients) and those with an EF between 0.20 and 0.30 (P = NS). Risk factors for death included heart failure and old age.
Conclusions: OMVP for MR in the setting of ischemic cardiomyopathy and low EF appear to improve ventricular function, medium-term patient symptomatology, and survival.