Risk factors and mortality associated with deep sternal wound infections following coronary bypass surgery with or without concomitant procedures in a UK population: a basis for a new risk model?

Deep sternal wound infection (DSWI) is a rare but serious complication following coronary artery bypass surgery. Our study investigates the risk factors and mortality associated with DSWI with other risk models for DSWI. Data was collected prospectively on 7602 patients undergoing coronary artery bypass grafting±concomitant surgery between April 1999 and September 2009 including DSWI. All 13 Society for Thoracic Surgeons (STS) risk scoring variables were assessed using logistic regression in relation to developing DSWI. The STS risk scores were evaluated using the area under the receiver operating curve. A total of 44 (0.59%) patients developed DSWI. These patients had a higher mortality (9.1%) than patients without DSWI (2.6%) (P=0.03). The mean preoperative and combined STS scores were significantly higher in the DSWI patient group compared to the non-DSWI group (9.46±4.30 and 8.76±3.86 vs. 7.07±4.25 and 6.51±4.11, P=0.0003 and P=0.0005, respectively). Logistic regression identified age [odds ratio (OR)=1.055], body mass index (OR=1.076), diabetes (OR=2.00) and chronic lung disease (OR=2.47) as the significant independent determinants of DSWI from the variables considered. Mortality rates and mean STS scores are higher in patients requiring re-opening for DSWI. Not all the STS risk factors were predictors of DSWI in our population.