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

Summary

Objectives

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.

Methods

We retrospectively studied 94 consecutive patients admitted in our intensive care unit (ICU) and operated before completion of standard antimicrobial therapy.

Results

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 ≥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.

Conclusions

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.

Introduction

Although antibiotics are the cornerstone of therapy for infective endocarditis, surgery is necessary in a large proportion of patients.1, 2, 3 Indeed, to achieve the best possible outcomes, surgical intervention during treatment is required in 25–30% of patients with infective endocarditis, and evidence is growing that a combined medical–surgical approach leads to reduced short term mortality in both prosthetic and native-valve infective endocarditis.4, 5, 6 However, the optimal duration of antibiotic treatment before surgery is unknown. A prolonged treatment prior to surgery may allow sterilisation of infected valves but may expose to the risk of disease evolution with complications such as emboli or acute valve failure. On the other hand, a shorter antibiotherapy prior to surgery may result in surgery of infected valves with a theoretical impact on endocarditis relapse and/or reinfection. To evaluate the role of prior antibiotherapy on positivity of heart valve culture and outcome, we studied 94 consecutive patients admitted in our intensive care unit and operated before completion of a standard course of intravenous antibiotic therapy.