Multivariate analysis of risk factors for deep and superficial sternal infection after coronary artery bypass grafting at a tertiary care medical center

Abstract

Identification of modifiable risk factors for sternal infection is essential for the development and institution of practices that decrease the incidence of these infections. This study analyzed 4004 consecutive patients undergoing coronary artery bypass grafting performed at a single institution between January 1996 and May 2003. Specific risk factors for both superficial and deep sternal wound infection were identified by univariate and multivariate analysis. The incidence of superficial sternal wound infections was 2.2% ( N = 87) while the incidence of deep sternal wound infections was 1.8% ( N = 73). Risk factors for superficial sternal infection identified by multivariate analysis include increasing body mass index (BMI) (OR 1.089, 95% CI 1.057–1.122, P < 0.001), female gender (OR 1.412, 1.108–1.717, P = 0.036), active smoking (OR 1.856, 1.079–3.193, P = 0.025), utilization of bilateral internal mammary arteries (OR 7.546, 3.175–17.935, P < 0.001), and transfusion of ≥4 units of packed red blood cells postoperatively (OR 2.009, 1.158–3.485, P = 0.013). Risk factors for deep sternal infection include increasing BMI (OR 1.077, 1.042–1.114, P < 0.001), diabetes mellitus (OR 2.412, 1.376–4.231, P = 0.002), and transfusion with ≥2 units of platelets postoperatively (OR 2.787, 1.279–6.071, P = 0.010). These data suggest that cessation of smoking, improved blood glucose management, preoperative weight loss, limitation of transfusions, and discriminate use of bilateral internal mammary arteries are all practices that may decrease the incidence of postoperative wound complications following coronary revascularization.