Background: Perioperative myocardial ischemia occurs in 20-40% of patients at risk for cardiac morbidity and is associated with a ninefold increase in risk of cardiac morbidity.
Methods: In a prospective, double-blinded, clinical trial, we studied 190 patients with or at risk for coronary artery disease in two study groups with a 2:1 ratio (clonidine, n = 125 vs. placebo, n = 65) to test the hypothesis that prophylactic clonidine reduces the incidence of perioperative myocardial ischemia and postoperative death in patients undergoing noncardiac surgery. Clonidine (0.2 mg orally as well as a patch) or placebo (tablet and patch) was administered the night before surgery, and clonidine (0.2 mg orally) or placebo (tablet) was administered on the morning of surgery. The patch or placebo remained on the patient for 4 days and was then removed.
Results: The incidence of perioperative myocardial ischemia was significantly reduced with clonidine (intraoperative and postoperative, 18 of 125, 14% vs. placebo, 20 of 65, 31%; P = 0.01). Prophylactic clonidine administration had minimal hemodynamic effects. Clonidine reduced the incidence of postoperative mortality for up to 2 yr (clonidine, 19 of 125 [15%] vs. placebo, 19 of 65 [29%]; relative risk = 0.43 [confidence interval, 0.21-0.89]; P = 0.035).
Conclusions: Perioperative administration of clonidine for 4 days to patients at risk for coronary artery disease significantly reduces the incidence of perioperative myocardial ischemia and postoperative death.