A study that could change clinical practice found that using the continued-release beta-blocker metoprolol (Toprol XL) in patients having noncardiac surgery reduced their risk of myocardial infarction (MI) but increased their risk of disabling stroke and death. Findings from the PeriOperative ISchemic Evaluation (POISE) study suggest that for every 1,000 patients who get the drug, 15 MIs would be prevented, but five additional severe disabling strokes and eight deaths also would result.

The POISE study involved 8,351 patients age 45 years or older who were undergoing noncardiac surgery and had or were at risk for atherosclerotic disease. Patients were randomly selected to receive either Toprol XL or placebo started 2 to 4 hours preoperatively and continued for 30 days.

Of those who took Toprol XL, 5.8% experienced cardiovascular death, nonfatal MI, or nonfatal cardiac arrest, compared with 6.9% of those who took a placebo. Stroke occurred in 1% of those who took the drug, compared with 0.5% who took a placebo. Most MIs and strokes occurred in the first few postoperative days. Total mortality rates were 3.1% for those who took the drug and 2.3% for those who had a placebo. In patients who had sepsis, twice as many deaths occurred in those who took Toprol XL as in those who took a placebo.

Researchers, who presented their findings at the American Heart Association (AHA) 2007 Scientific Sessions in Orlando, Fla., say they don't have enough evidence to predict who'd benefit and who'd be at risk from perioperative use of these beta-blockers. They suggest that physicians carefully weigh the risks and benefits of perioperative use of Toprol XL. Their results don't apply to patients undergoing surgery who already are taking beta-blockers or to those whose health care provider planned to prescribe a beta-blocker within 30 days of surgery.

For more information about POISE findings, visit http://www.theheart.org.