Wound Infections after Coronary Artery Bypass Grafting

Deep sternal wound infection (DSWI), also called mediastinitis, is a serious complication after median sternotomy with an incidence of 1 to 5%. While superficial sternal wound infections (SSWI) involves the skin, subcutaneous tissue, and pectoralis fascia only and has much less mortality (0.5 to 9%), DSWI involves retrosternal space, prolongs the hospital stay by an average of 20 days and is associated with a mortality of 10 to 47% which is double the mortality of those without mediastinitis [1,2]. The incidence of DSWI is particularly high in the presence of Diabetes Mellitus (DM), smoking history, chronic obstructive pulmonary disease (COPD), osteoporosis and obesity [1-4]. Prolonged stay in the Intensive Care Unit (ICU), use of assist devices and reoperation boost the incidence as well. Coronary Artery Bypass Grafting (CABG) is associated with a higher rate of sternal wound infections compared with other surgeries performed through the same surgical approach. Moreover, the technique used in harvesting the internal mammary artery (IMA) for CABG was found to influence the rate of sternal wound infections [5]. When the artery is dissected along the accompanying veins, fascia, adipose tissue and lymphatics (pedicled harvest), the sternal blood flow is decreased by up to 90%, thus increasing the rate of sternal wound infection. In contrast, dissecting the artery free from the surrounding tissues (skeletonized technique) has been shown to preserve the blood supply of the sternum and thereby reducing the rate of sternal wound infections.