Influence of preoperative antibiotherapy on valve culture results and outcome of endocarditis requiring surgery

Although medical-surgical therapy can reduce mortality in patients with infective endocarditis (IE), the optimal timing of surgery remains controversial. We evaluated the influence of preoperative antimicrobial therapy duration on positivity of valve culture and outcome.We retrospectively studied 94 consecutive patients admitted in our intensive care unit (ICU) and operated before completion of standard antimicrobial therapy.Of 90 valves cultured, 46 were positive. In univariate analysis, time between diagnosis and surgery as well as duration of adequate therapy before surgery was shorter in patients with positive valve cultures as compared to those with negative cultures. A preoperative duration of adequate therapy > or =7 days was strongly associated with negative valve cultures (76% vs. 22%, P<0.001). Logistic regression analysis identified duration of preoperative adequate antimicrobial therapy as an independent risk factor for positive valve culture. However, there was no significant difference between patients with positive or negative valve culture regarding the occurrence of complications, ICU and hospital length of stay, hospital and long-term mortality, endocarditis relapse and reinfection, as well as treatment failure.Although the duration of adequate preoperative antimicrobial therapy is associated with the positivity of valve culture, the latter factor does not influence short- or long-term outcome.