Perioperative β blockers in patients having non-cardiac surgery: a meta-analysis

Background: American College of Cardiology and American Heart Association (ACC/AHA) guidelines on perioperative assessment recommend perioperative β blockers for non-cardiac surgery, although results of some clinical trials seem not to support this recommendation. We aimed to critically review the evidence to assess the use of perioperative β blockers in patients having non-cardiac surgery. Methods: We searched Pubmed and Embase for randomised controlled trials investigating the use of β blockers in non-cardiac surgery. We extracted data for 30-day all-cause mortality, cardiovascular mortality, non-fatal myocardial infarction, non-fatal stroke, heart failure, and myocardial ischaemia, safety outcomes of perioperative bradycardia, hypotension, and bronchospasm. Findings: 33 trials included 12 306 patients. β blockers were not associated with any significant reduction in the risk of all-cause mortality, cardiovascular mortality, or heart failure, but were associated with a decrease (odds ratio [OR] 0·65, 95% CI 0·54-0·79) in non-fatal myocardial infarction (number needed to treat [NNT] 63) and decrease (OR 0·36, 0·26-0·50) in myocardial ischaemia (NNT 16) at the expense of an increase (OR 2·01, 1·27-3·68) in non-fatal strokes (number needed to harm [NNH] 293). The beneficial effects were driven mainly by trials with high risk of bias. For the safety outcomes, β blockers were associated with a high risk of perioperative bradycardia requiring treatment (NNH 22), and perioperative hypotension requiring treatment (NNH 17). We recorded no increased risk of bronchospasm. Interpretation: Evidence does not support the use of β-blocker therapy for the prevention of perioperative clinical outcomes in patients having non-cardiac surgery. The ACC/AHA guidelines committee should soften their advocacy for this intervention until conclusive evidence is available. Funding: None. © 2008 Elsevier Ltd. All rights reserved.