Beta blockers in patients undergoing non-cardiac surgery

POISE trial: Perioperative Ischemic Evaluation Study

8351 non-cardiac surgery patients at risk of perioperative cardiovascular complications randomised to the beta-blocker metoprolol or placebo. Metopropol reduced the incidence of myocardial infarction but increased the incidence of death and stroke. This led to much more selective use of beta-blockers for cardioprotection by anaesthetists and cardiologists. This study was a collaboration with Population Health Research Institute (PHRI), McMaster University, Canada.

Principal investigator

Professor Kate Leslie AO FAHMS (Australian arm)

Recruitment

8531 patients were enrolled between October 2002 and July 2007.

Participating countries

Australia, Canada and 21 other countries (190 hospitals)

Outcomes

Background
Trials of beta blockers in patients undergoing non-cardiac surgery have reported conflicting results. This randomised controlled trial, done in 190 hospitals in 23 countries, was designed to investigate the effects of perioperative beta blockers.

Methods
We randomly assigned 8351 patients with, or at risk of, atherosclerotic disease who were undergoing non-cardiac surgery to receive extended-release metoprolol succinate (n=4174) or placebo (n=4177), by a computerised randomisation phone service. Study treatment was started 2-4 h before surgery and continued for 30 days. Patients, health-care providers, data collectors, and outcome adjudicators were masked to treatment allocation. The primary endpoint was a composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal cardiac arrest. Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00182039.

Findings
All 8351 patients were included in analyses; 8331 (99.8%) patients completed the 30-day follow-up. Fewer patients in the metoprolol group than in the placebo group reached the primary endpoint (244 [5.8%] patients in the metoprolol group vs 290 [6.9%] in the placebo group; hazard ratio 0.84, 95% CI 0.70-0.99; p=0.0399). Fewer patients in the metoprolol group than in the placebo group had a myocardial infarction (176 [4.2%] vs 239 [5.7%] patients; 0.73, 0.60-0.89; p=0.0017). However, there were more deaths in the metoprolol group than in the placebo group (129 [3.1%] vs 97 [2.3%] patients; 1.33, 1.03-1.74; p=0.0317). More patients in the metoprolol group than in the placebo group had a stroke (41 [1.0%] vs 19 [0.5%] patients; 2.17, 1.26-3.74; p=0.0053).

Interpretation
Our results highlight the risk in assuming a perioperative beta-blocker regimen has benefit without substantial harm, and the importance and need for large randomised trials in the perioperative setting. Patients are unlikely to accept the risks associated with perioperative extended-release metoprolol.

Funding

The Australian National Health and Medical Research Council, Canadian Institutes of Health Research and others.

Primary results publication

POISE Study Group, Devereaux PJ, Yang H, Yusuf S, Guyatt G, Leslie K, Villar JC, Xavier D, Chrolavicius S, Greenspan L, Pogue J, Pais P, Liu L, Xu S, Málaga G, Avezum A, Chan M, Montori VM, Jacka M, Choi P. Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a randomised controlled trial. Lancet. 2008 May 31;371(9627):1839-47.

Trial registration

ClinicalTrials.gov number NCT00182039.

Pubmed link

The abstract can be viewed on Pubmed