Metoprolol Associated with Lower Rates of Major CV Events in POISE Trial for High Risk Patients Undergoing Noncardiac Surgery

November 7, 2007 By Scott P. Williams [mailto:swilliams@perfuse.org]

Orlando, FL: The results of the POISE trial indicate that, when compared to placebo, treatment of patients with the beta-blocker metoprolol prior to and following non-cardiac surgery is associated with a reduced occurrence rate of major cardiovascular events at 30 days. The results were released today for the American Heart Association’s Scientific Sessions.

The POISE study enrolled patients over the age of 45 (mean=69 years old), who were undergoing non-cardiac surgery which would require a hospital stay of 24 hours or longer. To be included in the study patients also had to be considered at high risk for a cardiovascular event, which was defined by the patient meeting at least one of the following criteria: 1.)	Coronary artery disease (43% of patients) 2.)	Peripheral vascular disease (41% of patients) 3.)	History of stroke due to atherothrombotic disease (15% of patients) 4.)	Hospitalization for congestive heart failure within 3 years of randomization 5.)	Undergoing major vascular surgery 6.)	3 of 7 other high risk criteria

Prior to surgery patients were randomized in a double-blind, 1:1 manner to receive either metorpolol (n=4174) or placebo (n=4177). The metoprolol group of patients received two 100 mg controlled release doses of metoprolol (one dose 2-4 hours pre-surgery and the other 0-6 hours post-surgery), followed by daily 200 mg doses for the next 30 days. 42% of the study patients underwent a vascular procedure, 22% an intraperitoneal procedure, 21% an orthopedic procedure, and 15% underwent an additional form of surgery.

The occurrence of at least one of three major cardiovascular events (major cardiovascular death, nonfatal myocardial infarction, and nonfatal cardiac arrest) served as the POISE trial’s primary endpoint. 6.9% of the patients who received placebo suffered a major cardiovascular event, compared to only 5.8% of the patients who received metoprolol (p=0.04). Additionally, the group of patients who received metoprolol displayed lower occurrence for revascularization (0.3% vs. 0.6%, p=0.01) and atrial fibrillation (2.2% vs. 2.9%, p=0.04).

These positive benefits displayed by the metoprolol group were offset by increased rates of total mortality (3.1% vs. 2.3%, p=0.03), stroke (1.0% vs. 0.5%, p=0.005), hypotension (15.0% vs. 9.7%, p<0.0001), and significant bradycardia (6.6% vs. 2.4%, p<0.0001) among this same group of patients. The increase in the rates of hypotension and bradycardia due to the use of metoprolol displayed in the POISE trial are similar to the results of the MaVS and DIPOM trials. Unlike the POISE trial the patients treated with metoprolol in the MaVS and DIPOM trials displayed no benefit with regard to clinical events.

Overall, metoprolol treatment was associated with a reduction in the rate of major cardiovascular events among the patients, but the increase in the overall mortality, stroke, significant hypotension, and significant bradycardia rates suggest that routine of the drug may not be the best way to reduce cardiovascular events in high risk patients.

The trial was sponsored by AstraZeneca.

References 1. Originally presented at AHA Scientific Sessions 2007 by Dr. P.J. Deveraux.