Risk factors and treatment of deep sternal wound infection after cardiac operation

Although deep sternal wound infection (DSWI) after cardiac surgery is infrequent, its consequences are serious. The purposes of this study were to define the risk factors, and to establish the best surgical treatment for DSWI.

Retrospective analysis for 863 patients who underwent cardiac surgery was performed. The patients were divided into the DSWI group (n=17) and the non-infection group (n=846). Preoperative, perioperative, and postoperative variables were compared between the two groups using univariate and multivariate logistic regression analysis. The modality of treatment for DSWI was also analyzed.

The incidence of DSWI was 1.97%. Independent predictors for DSWI were concomitant coronary artery bypass grafting (CABG) with valve or aortic surgery [odds ratio, 4.1; 95% confidence interval, (1.1, 15.1)] and postoperative use of intraaortic balloon pumping [4.4, (1.6, 12.3)]. An independent predictor in isolated CABG patients was emergency operation [10.9, (2.7, 44.7)]. Four of 17 patients died. Methicillin-resistant Staphylococcus aureus (MRSA) was cultured from 10 (58.8%) patients, and all four of the deceased subjects died of its infection. Seventeen patients were treated by debridement, primary closure, and the addition of an omentum or muscle flap if necessary.

Patients in poor perioperative condition are at high risk for the development of this infection. It was difficult to establish the best treatment, owing to the small series of this study. Mortality and morbidity of DSWI due to MRSA was high.