Wound complications after median sternotomy. Relationship to internal mammary grafting

Case histories of 2582 patients requiring median sternotomy for coronary artery bypass grafting between January 1982 and August 1986 were retrospectively reviewed. Only saphenous vein grafts were used in 230 patients, one mammary artery graft was used in 1626 patients, and both mammary arteries were used in 726 patients. The relationship of potential risk factors and wound complication was evaluated. The overall incidence of wound complications was 0.81%-0.43% in the saphenous vein graft group, 0.49% in the single mammary group, and 1.65% in the bilateral mammary group. Graft type and a number of potential risk factors were analyzed in a logistic regression analysis to determine significant predictors of wound complications. The results indicated that pneumonia, obesity, reexploration, use of the intraaortic balloon pump, and diabetes were significant risk factors contributing to the probability of wound complications. Bilateral mammary grafting was significantly associated with the increased probability of a wound complication developing. Bilateral mammary grafting increased the chance of wound complication nearly five times that of saphenous vein grafting and three times that of single mammary grafting. Mammary artery grafts have been shown to achieve greater long-term patency than saphenous vein grafts, and their continued use is encouraged. However, the potential for increased wound problems should be considered along with other significant preoperative risk factors such as insulin-dependent diabetes, chronic pulmonary disease, and obesity.