Anaesthetists should wait for better evidence of benefit

More than a million patients each year develop cardiovascular complications arising from non-cardiac surgery in the United States alone, and effective strategies and interventions to reduce perioperative cardiac morbidity are badly needed.1 2 The best perioperative outcomes for patients at such risk depend partly, as always, on taking a good history, completing a relevant clinical examination, and ordering appropriate investigations.3 But the best strategies for protecting high risk patients from cardiac ischaemia during surgery are still not clear.

One issue—the use of perioperative β blockers—is particularly controversial, and a systematic review and meta-analysis by Devereaux et al published recently in the BMJ sheds further doubt on previous evidence.4 Unlike many previous studies, which have found that perioperative β blockers reduce the risk of major cardiovascular events, this meta-analysis concludes that the evidence is encouraging but too unreliable to allow definitive conclusions to be drawn.4

This analysis by Devereaux et al includes 22 clinical trials, all published, in which 2437 patients were randomised.4 Thus it is considerably more comprehensive than previous reviews by Auerbach …