POISE showed that for every 1000 patients receiving metoprolol, 15 were prevented from suffering a myocardial infract, 3 from requiring cardiac revascularization along with 7 new cases of atrial fibrillation, but at a cost of causing an excess 8 deaths, 5 strokes, 53 hypotensive events and 42 episodes of bradycardia.

The harm associated with perioperative beta-blockade, at least in the form of non-titrated extended-release metoprolol, is greater than the demonstrated benefit. For every two cases of myocardial infract avoided there is one excess death.

summary

• POISE Study Group, P J Devereaux, Homer Yang, Salim Yusuf, Gordon Guyatt, Kate Leslie, Juan Carlos Villar, Denis Xavier, Susan Chrolavicius, Launi Greenspan, Janice Pogue, Prem Pais, Lisheng Liu, Shouchun Xu, German Málaga, Alvaro Avezum, Matthew Chan, Victor M Montori, Mike Jacka, and Peter Choi.
• McMaster University, Faculty of Health Sciences, Clinical Epidemiology and Biostatistics, Room 2C8, 1200 Main Street West, Hamilton, ON, L8N 3Z5, Canada. philipj@mcmaster.ca
• Lancet. 2008 May 31;371(9627):1839-47.

BackgroundTrials 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.MethodsWe 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.FindingsAll 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).InterpretationOur 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.

This article appears in the collections: Peri-operative beta blockade and Landmark articles in Anesthesia.

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