Antibiotic prophylaxis in cardiac surgery: Systematic review and meta-analysis

Background: Antibiotic prophylaxis is recommended in cardiac surgery. Current debate concerns the type of antibiotic(s), dosing and the duration of prophylaxis. Methods: Systematic review of randomized controlled trials comparing one antibiotic regimen versus another in cardiac surgery. We searched The Cochrane Library, PubMed, LILACS, conference proceedings and bibliographies. Two reviewers independently extracted the data. The primary outcome was deep sternal wound infections (DSWIs). Meta-analysis was performed using the Mantel-Haenszel fixed-effect method. Risk ratios (RRs) with 95% confidence intervals (95% CIs) are reported. Results: Fifty-nine trials were included. There were no significant differences in DSWI or all other categories of surgical site infections (SSIs) for antibiotic prophylaxis with β-lactams comprising a Gram-negative spectrum of coverage versus prophylaxis targeting Gram-positive bacteria, but the former led to a significantly lower rate of post-operative pneumonia (RR 0.68, 95% CI 0.51-0.90) and all-cause mortality (RR 0.66, 95% CI 0.47-0.92). In trials comparing different antibiotic regimens for different durations, prophylaxis duration of ≤24 h post-operation led to higher rates of DSWI (RR 1.83, 95% CI 1.25-2.66), any sternal SSI, surgical interventions for SSI and endocarditis compared with longer duration prophylaxis. There was no advantage of regimens lasting >48 h post-operation. In the comparison of glycopeptides versus β-lactams, an advantage of glycopeptides was observed when comparators were given for similar duration and for β-lactams when given for a longer duration than the glycopeptides. There was no significant advantage of high antibiotic dosing. Conclusions: Evidence supports second- or third-generation cephalosporins for cardiac surgery prophylaxis and points at a possible advantage of prophylaxis prolongation up to 48 h post-operatively.