The POISE trial: Perioperative use of beta-blockers [Classics Series]

1. The POISE trial was a randomized controlled trial exploring the effect of perioperative beta-blockers on cardiac death, nonfatal myocardial infarctions, and nonfatal cardiac arrest.

2. Perioperative oral extended-release metoprolol was found to reduce the risk of nonfatal myocardial infarction, while increasing the risk of stroke and mortality when compared to placebo.

Original Date of Publication: May 31, 2008

Study Rundown: With recent advances in non-cardiac surgery allowing for better treatment of diseases and improvements in quality of life, there have been substantial increases in the number of patients undergoing surgeries. These surgeries, however, are associated with increased risk of cardiac events. Numerous therapies have been investigated as prophylaxis against cardiac events in the perioperative state. The PeriOperative ISchemic Evaluation (POISE) trial was a randomized controlled trial published in 2008 exploring the effect of perioperative metoprolol in patients undergoing non-cardiac surgery. Perioperatively, beta-blockers are thought to protect against myocardial ischemia, while potentially increasing the risk of hypotension and bradycardia.

In summary, the POISE trial demonstrated that perioperative beta-blockade significantly reduced the risk of perioperative myocardial infarctions (HR 0.73; 95%CI 0.60-0.89) compared to placebo. Patients treated with beta-blockers, however, also experienced significantly higher rates of stroke (HR 2.17; 95%CI 1.26-3.74) and death (HR 1.33; 95%CI 1.03-1.74). Thus, patients must be carefully counseled regarding the risks and benefits of initiating perioperative beta-blockers for cardiac protection.

Click to read the study in The Lancet

Lead Study Investigator, Dr. P.J. Devereaux, MD, PhD, FRCPC, talks to 2 Minute Medicine: McMaster University, Department of Clinical Epidemiology and Biostatistics, Associate Professor.

“There is little doubt that initiating a beta-blocker anytime prior to noncardiac surgery has benefit (i.e., it prevents perioperative myocardial infarction). It is also important to recognize the risk related to perioperative beta-blockers (i.e., an increased risk of stroke and death). These complications appear to primarily occur through hypotension on surgical floors. I believe the take away messages from POISE are that controlling the sympathetic system in the perioperative period has benefit, but we need to find a way to do it safely. There is the potential that other drugs (e.g., clonidine) or other processes (e.g., more intense monitoring of hemodynamics on surgical floors) may achieve this goal. A final lesson learned from POISE is that we need large trials to establish actual effects.”

In-Depth [randomized controlled study]: The final analysis involved 8,351 patients from 190 hospitals in 23 countries randomized to either perioperative treatment with extended-release metoprolol or placebo. Patients were eligible for the trial if they were ≥45 years, were undergoing non-cardiac surgery, had expected hospitalization ≥24 hours, and had elevated risk of perioperative cardiac events (e.g., history of coronary artery disease, stroke, hospitalization for congestive heart failure, undergoing major vascular surgery). Exclusion criteria included heart rate <50 beats per minute, second/third-degree heart block, asthma, treatment with a beta-blocker, and prior adverse reaction to beta-blocker. The primary outcome was a composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal cardiac arrest at 30 days.

Beta-blockers were found to significantly reduce the incidence of the primary endpoint compared to placebo (HR 0.84; 95%CI 0.70-0.99), due to a significant reduction in myocardial infarctions (HR 0.73; 95%CI 0.60-0.89). Compared to placebo, perioperative beta-blockade was also found to significantly increase the risk of stroke (HR 2.17; 95%CI 1.26-3.74), clinically significant hypotension (HR 1.55; 95%CI 1.38-1.74), and clinically significant bradycardia (HR 2.74; 95%CI 2.19-3.43). Furthermore, the metoprolol group had a significantly higher risk of mortality (HR 1.33; 95%CI 1.03-1.74).

Image: PD

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