Risk factors for wound infection after off-pump coronary artery bypass grafting: Should bilateral internal thoracic arteries be harvested in patients with diabetes?

Objective: Wound infection is a rare but life-threatening complication after coronary artery bypass grafting. Risk factors for wound infection after off-pump bypass grafting and the validity of using bilateral internal thoracic arteries harvested in a skeletonized fashion remain unclear, especially in patients with diabetes. Methods: The data of 1500 consecutive patients having off-pump bypass grafting were prospectively collected from our database based on EuroSCORE. This cohort represents 95% of all patients undergoing coronary bypass during that period and 77% of patients undergoing off-pump bypass grafting who received bilateral internal thoracic artery grafts. Univariate and multivariate analyses were performed for patients with and without wound infection and in the diabetic subgroup. Results: Ninety-eight patients had wound infections: 76, impaired wound healing; 7, superficial sternal wound infection; and 12, deep sternal wound infection. Patients with wound infections had a higher prevalence of female gender, atrial fibrillation, history of congestive heart failure, chronic renal failure, peripheral vascular disease, and diabetes. Patients with a wound infection more frequently had bilateral internal thoracic artery grafting, longer operation time, longer hospital stay, and a higher mortality rate. Blood transfusions were required in 43.9% of patients with wound infections and 28.1% of those without wound infections. On logistic regression analysis, female gender and history of congestive heart failure, chronic renal failure, and diabetes mellitus were independent risk factors for wound infection. In patients with diabetes, female gender, atherosclerosis obliterans, chronic renal failure, and use of bilateral internal thoracic artery grafts were independent risk factors for wound infection. Conclusions: Risk factors for wound infection after off-pump coronary artery bypass grafting are comparable with those previously reported for conventional bypass grafting. In patients with diabetes, the use of bilateral internal thoracic arteries, even when harvested in a skeletonized fashion, is a risk factor. Thus, appropriate precautions should be taken in patients with diabetes.