NEW YORK (Reuters Health) – Perioperative antibiotics started more than 24 hours before cardiac surgery may be more effective than shorter-duration prophylaxis in preventing sternal surgical site infections, according to the results of a meta-analysis reported in the Annals of Surgery online March 15.

However, the authors note that the results might be skewed by selection bias in the original studies.

Dr. Dominik Mertz and colleagues at McMaster University in Hamilton, Ontario, Canada note that up to 6% of cardiac operations are complicated by sternal wound infections. “Recommendations for antibiotic prophylaxis in cardiac surgery vary,” they explain, “ranging from single infusions of antibiotics to durations up to 72 hours.”

To see if antibiotic prophylaxis given for less than 24 hours or for 24 hours and longer affected the risk of sternal surgical site infections, the team identified 12 relevant randomized trials involving 7893 patients undergoing open heart surgery.

Compared to short-term prophylaxis, longer-term antibiotic therapy reduced the risk of sternal surgical site infections by 38%, and the risk of deep sternal infections by 68%, according to the report. Even so, there were no overall differences in adverse events and mortality between the two groups.

“Importantly, the risk of bias was high in 11 of the 12 studies included,” Dr. Mertz and colleagues point out. Also, the antibiotic regimens used were heterogeneous.

While saying a large randomized trial is needed, they nevertheless conclude: “This systematic review offers the best possible estimate based on the evidence available, and the data argues against noninferiority of short-term antibiotic prophylaxis of <24h in cardiac surgery.”

Reference:
Does Duration of Perioperative Antibiotic Prophylaxis Matter in Cardiac Surgery? A Systematic Review and Meta-Analysis
Ann Surg 2011.