A systematic review 1 including 22 studies with a total of 2,437 subjects was abstracted in DARE. A moderate number of major peri-operative cardiovascular events (18 cardiovascular deaths, 58 nonfatal MIs and 7 nonfatal cardiac arrests) were observed in the trials. Treatment with peri-operative beta-blockers was not associated with any significant treatment benefit on any of the individual outcomes of total mortality, cardiovascular mortality, nonfatal MI, nonfatal cardiac arrest, nonfatal stroke or congestive heart failure. For the composite outcome measure of major peri-operative cardiovascular event (cardiovascular death, nonfatal MI, or nonfatal cardiac arrest), a statistically significant treatment benefit in favour of treatment with beta-blockers was observed in comparison with placebo or usual care (RR 0.44, 95% CI: 0.20 to 0.97). Moderate heterogeneity was observed across the trials. Treatment with beta-blockers was also associated with a significant increase in the risk of experiencing bradycardia needing treatment (RR 2.27, 95% CI: 1.53 to 3.36) and hypotension needing treatment (RR 1.27, 95% CI: 1.04 to 1.56).
Comment: The quality of evidence is downgraded by inconsistency (variability in results across studies) and by imprecise results (limited study size for each comparison).
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