Postoperative Prophylactic Administration of β-Adrenergic Blockers in Patients at Risk for Myocardial Ischemia

Publisher Website
Google Scholar
Abstract
Perioperative myocardial ischemia (MI) is associated with postoperative cardiac morbidity. Postoperative sympatholysis may reduce the incidence of MI. This study evaluated such a reduction postoperatively with the administration of prophylactic b-blockers in pa- tients undergoing elective total knee arthroplasty with epidural anesthesia and postoperative epidural analge- sia. One hundred seven patients were preoperatively randomized into two groups, control and b-blockers, who received postoperative esmolol infusions on the day of surgery and metoprolol for the next 48 h to main- tain a heart rate less than 80 bpm. Patients were fol- lowed for ST segment depression by using a Holter monitor and adverse cardiac outcomes. Postoperative electrocardiographic ischemia was significantly more prevalent in the control group compared with the b-blocker group during esmolol blockade (0 of 52 vs 4 of 55; P 5 0.04) and tended to be more common in the control group the next two days (8 of 55 vs 3 of 52; P 5 0.135). In addition, the number of ischemic events (con- trol, 50; b-blockers, 16) and total ischemic time (control, 709 min; b-blocker, 236 min) were also significantly dif- ferent from the control group. Myocardial infarctions and cardiac events were more common in the control group, but these differences were not significant. Our results suggest that the use of prophylactic b-blocker therapy may reduce the incidence of postoperative MI.