Clinical question: What is the impact of peri-operative beta blockers on cardiovascular morbidity and mortality in patients undergoing surgery under general anesthesia?
Background: Studies evaluating the effects of peri-operative beta blockers on cardiovascular outcomes have yielded conflicting results.
Study design: Systematic review.
Synopsis: This review included 89 randomized controlled trials (RCTs) of peri-operative beta blocker administration for patients undergoing surgery under general anesthesia. For noncardiac surgery (36 trials), beta blockers were associated with an increase in all-cause mortality (RR 1.24, 95% CI 0.99 to 1.54) and cerebrovascular events (RR 1.59, 95% CI 0.93 to 2.71). Beta blockers significantly increased the occurrence of hypotension (RR 1.50, 95% CI 1.38 to 1.64) and bradycardia (RR 2.24, 95% CI 1.49 to 3.35). In noncardiac surgery, beta blockers significantly reduced occurrence of acute myocardial infarction (AMI) (RR 0.73, 95% CI 0.61 to 0.87), myocardial ischemia (RR 0.43, 95% CI 0.27 to 0.70), and supraventricular arrhythmias (RR 0.72, 95% CI 0.56 to 0.92). No effect was found on ventricular arrhythmias, congestive heart failure, or length of hospital stay.
For cardiac surgery (53 trials), peri-operative beta blockers were associated with a significant reduction in ventricular arrhythmias (RR 0.37, 95% CI 0.24 to 0.58), supraventricular arrhythmias (RR 0.44, 95% CI 0.36 to 0.53), and length of hospital stay (by 0.54 days, 95% CI -0.90 to -0.19). No effect was found on all-cause mortality, AMI, myocardial ischemia, cerebrovascular events, hypotension, bradycardia, or congestive heart failure.
These results do not provide sufficient evidence to change recommendations from current ACC/AHA guidelines for peri-operative beta blocker administration.
Bottom line: For noncardiac surgeries, beta blockers might increase all-cause mortality and stroke while reducing supraventricular arrhythmias and acute myocardial infarctions. Because much of the evidence is from low- to moderate-quality trials, there is not sufficient evidence to modify current recommendations regarding the use of peri-operative beta blockers.