Perioperative administration of beta-blockers

Background. The perioperative administration of beta blockers is a controversial issue. Numerous trials failed to show any significant benefit or disadvantage because of low event rates and insufficient statistical power. Methods. In July 2005 McGory et al. and Devereaux et al. separately published 2 meta-analyses, raising the question of the perioperative administration of beta blockers for patients undergoing non-cardiac surgery. In February 2006, Schouten et al. published an additional meta-analysis concerning the same question. This evidence is supplemented by the publication of Lindenauer et al. in 2005. These trials will be critically appraised in this review. Results. McGory et al. concluded from their data that the perioperative administration of beta blockers significantly reduced cardiovascular mortality. However, this conclusion is clearly not valid because of methodological deficits of the meta-analysis. In addition, the publications by Devereaux et al. and Schouten et al. did not support the results of the analysis by McGory et al.. Conclusions. There is still no clear evidence to prove a significant benefit for the unselected perioperative use of beta blockers in patients undergoing non-cardiac surgery. While high-risk patients and those undergoing major surgical procedures seem to profit, low-risk patients may be more harmed than helped by this intervention. The fact that 3 meta-analyses raising the same question produced substantially different results, underlines the importance of critically appraising each meta-analysis.