Are blood and valve cultures predictive for long-term outcome following surgery for infective endocarditis?

Objective: To evaluate whether perioperative bacteria identification in blood and/or in valve cultures can predict early and late outcome of surgery for infective endocarditis, a retrospective study was performed. Methods: Between January 1978 and December 1998, 232 patients, 79 (34.1%) female and 153 (65.9%) male with mean age of 44.95 ± 1.03 years (range 8-79) underwent surgery for infective endocarditis on a native (162 cases) or prosthetic (70 cases) valve. Patients were divided into three groups according to the perioperative x of microbiological tests: Group A: patients with preoperative positive blood cultures (83 cases); Group B: patients with positive valve cultures (35 cases); Group C: patients with negative blood and valve cultures (114 cases). Categorical values were compared by X 2 analysis, whereas continuous data were compared by ANOVA and Bonferroni correction for post hoc comparisons. Analysis of late survival and complications was performed with Kaplan-Meier and Log Rank test. Late mortality, reoperation, perivalvular leak, recurrence of infection were considered as treatment failure. All data were presented as mean ± standard error. Results: Hospital mortality was 10.8% (9/83) in Group A, 8.6% (3/35) in Group B, and 14.9% (17/114) in Group C (P = 0.52; not significant (NS)). Ten-year survival was 62.7 ± 8% in Group A, 43.9 ± 19% in Group B and 62.7 ± 7% in Group C (P = 0.38; NS). Ten-year freedom from reoperation was 85.2 ± 6% in Group A, 37.9 ± 20% in Group B and 80 ± 6% in Group C (P = 0.0034). Ten-year freedom from treatment failure was 56.3 ± 8% in Group A, 31.6 ± 16% in Group B and 55.3 ± 7% in Group C (P = 0.46; NS). Conclusions: Positive blood and tissue cultures are not predictive for hospital mortality and late treatment failure in patients with infective endocarditis. Positive valve cultures, a common finding in patients with staphylococcal endocarditis, are predictive for a higher risk of reoperation.