Impaired Left Ventricular Function Does Not Predict Worse Late Outcome after Isolated Mitral Valve Surgery

Background and aim of the study: The best timing for mitral valve surgery remains controversial. Decreased left ventricular function (LVF) is considered to be a predictor for increased mortality and is therefore an indication for surgery. The study aim was to investigate the independent effect of preoperative LVF on early and late mortality after mitral valve surgery.

Methods: Patients undergoing isolated mitral valve surgery between January 1998 and December 2010 at a single center were included for the analysis. Patients without recorded LVF, with active endocarditis, or patients lost to follow up were excluded. Patients were allocated to three groups based on their left ventricular ejection fraction (LVEF) measured using echocardiography as good (>50%), moderate (35-50%) or poor (<35%). A Cox regression analysis was performed to identify independent risk factors for late survival.

Results: A total of 549 patients underwent isolated mitral valve surgery. The 30-day mortality was not statistically different between groups (p = 0.579), and late survival was similar in all groups (log-rank, p = 0.130). A moderate or poor LVF was not identified as a risk factor for late mortality (HR 1.4 [0.9-2.2], p = 0.179; HR 1.8 [0.7-4.4], respectively, p = 0.213). The difference remained insignificant after correction for other risk factors (HR 1.4 [0.8-2.3], p = 0.192; HR 2.4 [0.9-6.7], respectively, p = 0.09).

Conclusion: A reduced LVF is not an independent risk factor for short- and long-term all-cause mortality in patients undergoing isolated mitral valve surgery for non-ischemic mitral valve disease.