Surgical treatment of infective mitral valve endocarditis: Predictors of early and late outcome

Background and aims of the study: The study aim was to review our experienc e in surgical treatment of infective mitral valve endocarditis, and to iden tify predictors of early and late outcome. Methods: Ninety-one consecutive patients (52 males, 39 females, mean age 55 .6 years) underwent surgery between 1973 and 1997 for endocarditis of isola ted mitral (n = 65, 71%), mitral and aortic (n = 25, 28%) and mitral, aorti c and tricuspid valves (n = 1, 1%). Native valve endocarditis (NVE) was pre sent in 60 patients (66%) and prosthetic valve endocarditis (PVE) in 31 (34 %). The main indications for surgery were heart failure in 32 patients, val ve dysfunction in 23, vegetations in 21, and persistent sepsis in 11. Eight y-six patients (95%) were in NYHA classes III-IV, and 58 (64%) had active c ulture-positive endocarditis at surgery. Mechanical valves were implanted i n 73 patients and bioprosthetic valves in 13; valves were repaired in five patients. The impact of 46 parameters on early and late outcome was defined by means of univariate and multivariate statistical analysis. Follow up wa s complete (mean 5.5 years; range: 0-23.1 years; total 507.3 patient-years) . Results: Operative mortality rate was 11% (n = 10). Recurrent infection was recorded in five patients (6%), and reoperation was required in eight (9%) . Freedom from recurrent infection and reoperation at 10 years was 89.1% an d 87.8% respectively. There were 22 late deaths, 15 from cardiac causes. Ac tuarial survival rates for all patients at 5, 10 and 15 years were 73.0%, 6 2.7% and 58.7% (for hospital survivors, the corresponding rates were 81.9%, 69.7% and 66.0%). On multiple logistic regression and Cox proportional haz ards models, the following were independent predictors: preoperative pulmon ary edema (p = 0.01) for operative mortality; PVE (p = 0.02) for recurrence ; younger age (p = 0.02) and PVE (p = 0.02) for reoperation; male gender (p = 0.004) and longer ITU stay for survival (if all patients were included); male gender (p = 0.01) and myocardial invasion by infection (p = 0.02) for survival (if only the hospital survivors were analyzed). Conclusion: Surgery for infective mitral valve endocarditis carries a relat ively high, though acceptable, risk but provides satisfactory freedom from recurrent infection, reoperation and improved long-term survival. Analysis of these data demonstrated that the preoperative hemodynamic status was the major predictor of in-hospital outcome, PVE increased the risk for recurre nt infection and reoperation, whereas male gender and myocardial invasion b y the infective process critically reduced the probability of longterm surv ival. The type of offending pathogen, the activity of infection and the inv olvement of more than one valve did not appear to influence early and/or la te outcome.