Perioperative β-blockade (POBBLE) for patients undergoing infrarenal vascular surgery:: Results of a randomized double-blind controlled trial

Objective: To assess whether a pragmatic policy of perioperative beta-blockade, with metoprolol, reduced the 30-day cardiovascular morbidity and mortality and reduced the length of hospital stay in average patients undergoing infrarenal vascular surgery. Methods: This was a double-blind randomized placebo-controlled trial that occurred in vascular surgical units in four UK hospitals. Participants were 103 patients without previous myocardial infarction who had infrarenal vascular surgery between July 2001 and March 2004. Interventions were oral metoprolol (50 mg twice daily, supplemented by intravenous doses when necessary) or placebo from admission until 7 days after surgery. Hotter monitors were kept in place for 72 hours after surgery. Results: Eighty men and 23 women (median age, 73 years) were randomized, 55 to metoprolol and 48 to placebo, and 97 (94%) underwent surgery during the trial. The most common operations were aortic aneurysm repair (38%) and distal bypass (29%). Intraoperative inotropic support was required in 64% and 92% of patients in the placebo and metoprolol groups, respectively. Within 30 days, cardiovascular events occurred in 32 patients, including myocardial infarction (8%), unstable angina (9%), ventricular tachycardia (19%), and stroke (1%). Four (4%) deaths were reported. Cardiovascular events occurred in 15 (34%) and 17 (32%) patients in the placebo and metoprolol groups, respectively (unadjusted relative risk, 0.94; 95% confidence interval, 0.53-1.66; adjusted [for age, sex, statin use, and aortic cross-clamping] relative risk, 0.87; 95% confidence interval, 0.48-1.55). Time from operation to discharge was reduced from a median of 12 days (95% confidence interval, 9-19 days) in the placebo group to 10 days (95% confidence interval, 8-12 days) in the metoprolol group (adjusted hazard ratio, 1.71; 95% confidence interval, 1.09-2.66; P < .02). Conclusions: Myocardial ischemia was evident in a high proportion (one third) of the patients after surgery. A pragmatic regimen of perioperative beta-blockade with metoprolol did not seem to reduce 30-day cardiovascular events, but it did decrease the time from surgery to discharge.