To assess the intraoperative and postoperative hemodynamic effects of beta-blockade and its benefits in limiting
myocardial ischemia and
infarction, a group of 32 patients scheduled for
abdominal aortic aneurysm (AAA) surgery (group 1) was treated with oral
metoprolol immediately before surgery and with intravenous
metoprolol during the postoperative period. Mean age was 71 years, and mean ejection fraction was 56% (range 36% to 83%). Eight patients had a preoperative history of angina, 13 had a history of
myocardial infarction, and five had electrocardiographic evidence of prior
myocardial infarction. A group of 51 closely matched patients with AAA who did not receive
metoprolol served as controls (group 2). In group 1, overall hemodynamic tolerance of
metoprolol intraoperatively and postoperatively was good, and there was no incidence of
congestive heart failure,
hypotension, or
asthma. Furthermore, in group 1 significant reduction of systolic blood pressure and heart rate was consistently noted at frequent intraoperative intervals and for 48 hr after surgery, with only a transient reduction of cardiac index. In group 1, only one patient (3%) suffered an acute
myocardial infarction. In contrast, nine group 2 patients (18%; p less than .05) suffered perioperative
myocardial infarction. Furthermore, only four (12.5%) group 1 patients developed significant
cardiac arrhythmias as opposed to 29 group 2 patients (56.9%; p less than .001). These data demonstrate that beta-blockade with
metoprolol is effective in controlling systolic blood pressure and heart rate both intraoperatively and postoperatively in patients undergoing repair of AAA and can significantly reduce the incidence of perioperative
myocardial infarction and arrhythmias.