Good news for β-blockers in perioperative medicine

Myocardial ischemia is a relatively frequent complication in patients undergoing non-cardiac surgery and β-blockers may have a protective effect. β-blockers reduce the oxygen supply:demand ratio, and exert anti-inflammatory and anti-arrhythmic effects. However, randomized trials, specifically conducted to test this hypothesis, yielded conflicting results. The absolute risk for cardiac mortality and morbidity during and after non-cardiac surgery varies between patient groups defined by surgical risk categories, making it difficult to establish a risk:benefit ratio. We discuss the hypothesis that the protective effect of β-blockers on cardiovascular outcome differs across the different risk classes of surgical procedures, thereby explaining the conflicting evidence across studies. In particular, we examine the results of a recent meta-analysis that suggests that β-blockers may reduce mortality in patients under going high-risk non-cardiac surgery.