Metoprolol after Vascular Surgery - MaVS

Description:

The goal of the trial was to evaluate whether perioperative beta-blocker administration of metoprolol is associated with a reduction in cardiac events in patients undergoing noncardiac vascular surgery.

Study Design

Study Design:

Patients Screened: 2,848
Patients Enrolled: 496
Mean Follow Up: 6 months
Mean Patient Age: Mean age 66 years
Female: 24

Patient Populations:

Undergoing abdominal aortic surgery and infrainguinal or axillofemoral revascularization and American Society of Anesthesiology class 3 or less

Exclusions:

Current or recent beta-blocker use, current amiodarone use, airflow obstruction requiring treatment, history of CHF, history of atrioventricular block, previous adverse drug reactions to beta-blockers, and previous participation in the MaVS study

Primary Endpoints:

Composite of nonfatal myocardial infarction, unstable angina, new congestive heart failure (CHF), new atrial or ventricular dysrhythmia requiring treatment, or cardiac death at 30 days

Secondary Endpoints:

Study drug discontinuation due to bronchospasm, advanced heart blocks, hypotension, or bradycardia; incidence of reoperation or amputation; and the incidence of intraoperative hypotension and bradycardia requiring treatment by the attending anesthesiologists

Drug/Procedures Used:

Patients were randomized in a double-blind manner to either placebo (n = 250) or perioperative metoprolol (n = 246). Study drug was administered 2 hours prior to surgery and was continued during the hospitalization for up to 5 days.

Principal Findings:

Qualifying surgery was abdominal aortic in 46% of patients, infrainguinal in 42%, and extra-anatomical in 16%. All patients received either general anesthesia (44%), regional (14%), or combined (43%). Average cross-clamp time was 55 minutes and average surgery time was 2.7 hours. Median blood loss was 400 ml in the metoprolol group and 350 ml in the placebo group. Postoperative heart rate was lower in the metoprolol group (69.4 vs. 79.1 bpm, p < 0.001).

Study protocol was discontinued in 24.8% of the metoprolol group and 22.4% of the placebo group. There was no significant difference in the primary composite endpoint at 30 days between the treatment groups (10.2% in the metoprolol group vs. 12.0% of the placebo group, p = 0.57) or in any component of the composite endpoint. The most frequent of the components was myocardial infarction (7.7% for metoprolol vs. 8.4% for placebo, p = 0.87) and dysrhythmia (2.9% for metoprolol vs. 4.1% for placebo, p = 0.62). Cardiac events also did not differ at 6 months. Intraoperative complications were higher with metoprolol, including hypotension (53.7% vs. 40.8%), hypotension requiring treatment (46.3% vs. 33.6%), bradycardia (34.6% vs. 10.4%), and bradycardia requiring treatment (21.5% vs. 7.6%; all p < 0.01).

Interpretation:

Among patients undergoing noncardiac vascular surgery, perioperative beta-blocker administration of metoprolol was not associated with a reduction in the primary endpoint of cardiac event by 30 days compared with placebo.

While there was no reduction in cardiac events at 30 days with metoprolol, intraoperative complications were significantly higher with metoprolol. Results of the trials evaluating perioperative beta-blocker use have been mixed, with some trials showing a >90% relative risk reduction, and others such as the present study, showing a nonsignificant risk reduction. Results of the present study are very similar to those reported in the DIPOM trial, which did not show a benefit of perioperative metoprolol in diabetic patients undergoing vascular surgery, but did show an increase in hypotension and bradycardia. Based on data from these recent trials, prophylaxis perioperative beta-blocker use for high-risk patients undergoing vascular surgery should be reexamined.

References:

Yang H, Raymer K, Butler R, Parlow J, Roberts R. The effects of perioperative beta-blockade: results of the Metoprolol after Vascular Surgery (MaVS) study, a randomized controlled trial. Am Heart J 2006;152:983-90.

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices

Keywords: Intraoperative Complications, Myocardial Infarction, Perioperative Care, Risk Reduction Behavior, Hypotension, Bradycardia, Metoprolol, Heart Rate, Diabetes Mellitus


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