Sternal Wound Infections in Patients After Coronary Artery Bypass Grafting Using Bilateral Skeletonized Internal Mammary Arteries

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Abstract
This study evaluated the risks of sternal wound infections in patients undergoing myocardial revascularization using bilateral skeletonized internal mammary arteries (IMAs). The skeletonized IMA is longer than the pedicled one, thus providing the cardiac surgeon with increased versatility for arterial myocardial revascularization without the use of vein grafts. It is isolated from the chest wall gently with scissors and silver clips, and no cauterization is employed. Preservation of collateral blood supply to the sternum and avoidance of thermal injury enable more rapid healing and decrease the risk of sternal wound infection. From April 1996 to August 1997, 545 patients underwent arterial myocardial revascularization using bilateral skeletonized IMAs. The right gastroepiploic artery was used in 100 patients (18%). The average age of the patients was 65 years; 431 (79%) were men and 114 (21%) were women; 179 (33%) were older than 70 years of age; 166 (30%) were diabetics. The average number of grafts was 3.2 per patient. The 30-day operative mortality rate was 2% (n = 11). There were six perioperative infarcts (1.1%) and six strokes (1.1%); 9 patients had sternal infection (1.7%) and 15 (2.8%) had superficial infection. Risk factors for sternal infection were chronic obstructive pulmonary disease and emergency operation. Superficial sternal wound infections were more common in women and in patients with chronic obstructive pulmonary disease, renal failure, or peripheral vascular disease. The 1-year actuarial survival rate was 97%. Two of the six late deaths were not cardiac-related. Late dehiscence occurred in three patients (0.6%). The death rate (early and late) of patients with any sternal complication was higher than that of patients without those complications (33% vs. 2.7%). Routine arterial myocardial revascularization using bilateral skeletonized IMAs is safe, and postoperative morbidity and mortality rates are low, even in elderly patients and those with diabetes. Chronic obstructive pulmonary disease and emergency operations were found to be associated with an increased risk of sternal infections, and the authors recommend avoiding the use of bilateral skeletonized IMAs in patients with these preoperative risk factors.