Postoperative prophylactic administration of beta-adrenergic blockers in patients at risk for myocardial ischemia

Perioperative myocardial ischemia (MI) is associated with postoperative car diac morbidity. Postoperative sympatholysis may reduce the incidence of MI. This study evaluated such a reduction postoperatively with the administrat ion of prophylactic beta-blockers in patients undergoing elective total kne e arthroplasty with epidural anesthesia and postoperative epidural analgesi a. One hundred seven patients were preoperatively randomized into two group s, control and beta-blockers, who received postoperative esmolol infusions on the day of surgery and metoprolol for the next 48 h to maintain a heart rate less than 80 bpm. Patients were followed for ST segment depression by using a Holter monitor and adverse cardiac outcomes. Postoperative electroc ardiographic ischemia was significantly more prevalent in the control group compared with the beta-blocker group during esmolol blockade (0 of 52 vs 4 of 55; P = 0.04) and tended to be more common in the control group the nex t two days (8 of 55 vs 3 of 52; P = 0.135). in addition, the number of isch emic events (control, 50; beta-blockers, 16) and total ischemic time (contr ol, 709 min; beta-blocker, 236 min) were also significantly different from the control group. Myocardial infarctions and cardiac events were more comm on in the control group, but these differences were not significant. Our re sults suggest that the use of prophylactic beta-blocker therapy may reduce the incidence of postoperative MI.