Sternitis and mediastinitis after coronary artery bypass grafting. Analysis of risk factors.

As part of a quality control program, we analyzed possible risk factors in the development of sternitis and mediastinitis after coronary artery bypass grafting. From 1 January 1990 through 31 December 1991, 1,368 consecutive coronary artery bypass grafting procedures were performed at our institution, either alone or in combination with other procedures. Twenty-three patients (1.7%) developed sternitis and/or mediastinitis; 7 (30.4%) of these patients died in an early postoperative phase. Univariate analysis revealed the following statistically significant (p < or = 0.05) risk factors: perfusion time, length of stay in operating room of longer than 5 hours 30 minutes, presence at the operation of a certain surgical resident, revision for bleeding, and postoperative mechanical ventilation lasting longer than 72 hours. After multivariate analysis, statistically significant independent risk factors were: diabetes mellitus, recent cigarette-smoking, reoperation, presence of a certain surgical resident at the operation, revision for bleeding, and length of mechanical ventilation of longer than 72 hours. The use of both internal thoracic arteries was not, in this study, shown to be an independent risk factor. We conclude that although the technique of using both internal thoracic arteries for myocardial revascularization carries no extra risk by itself in the development of sternitis or mediastinitis, associated factors such as prolonged stay in the operating room and reoperation could be responsible for a higher frequency of sternitis-mediastinitis in patients who have undergone this procedure. Therefore, it is advisable to use this technique selectively in high-risk patients. Close surveillance and reporting of wound infections is mandatory to detect risk factor related to the surgical staff (such as Staphylococcus aureus dissemination).