Postoperative ST-segment elevation in coronary artery bypass surgery.

Using Holter monitors, 50 patients were monitored for vasospasm following coronary artery bypass surgery. Transient 2 mm ST-segment elevation was considered to be diagnostic or coronary vasospasm. Four patients (8 percent) had evidence of coronary vasospasm. Over 30 variables, including preoperative demographic information and medication, intraoperative technique, and postoperative medication, were subjected to multiple stepwise regression analysis. This analysis failed to show any association between preoperative prophylaxis with either nifedipine or nitrates (or other variables) and the postoperative development of coronary vasospasm. We conclude that the incidence of coronary vasospasm is more common than previously thought, and that a nifedipine or nitrate withdrawal, in this study, was not associated with an increased incidence of postoperative coronary vasospasm.