Efficacy and safety of out-of-hospital intravenous metoprolol administration in anterior ST-segment elevation acute myocardial infarction: insights from the METOCARD-CNIC trial.

Abstract

STUDY OBJECTIVE:

We seek to examine the efficacy and safety of prereperfusion emergency medical services (EMS)-administered intravenous metoprolol in anterior ST-segment elevation myocardial infarction patients undergoing eventual primary angioplasty.

METHODS:

This is a prespecified subgroup analysis of the Effect of Metoprolol in Cardioprotection During an Acute Myocardial Infarction trial population, who all eventually received oral metoprolol within 12 to 24 hours. We studied patients receiving intravenous metoprolol by EMS and compared them with others treated by EMS but not receiving intravenous metoprolol. Outcomes included infarct size and left ventricular ejection fraction on cardiac magnetic resonance imaging at 1 week, and safety by measuring the incidence of the predefined combined endpoint (composite of death, malignant ventricular arrhythmias, advanced atrioventricular block, cardiogenic shock, or reinfarction) within the first 24 hours.

RESULTS:

From the total population of the trial (N=270), 147 patients (54%) were recruited during out-of-hospital assistance and transferred to the primary angioplasty center (74 intravenous metoprolol and 73 controls). Infarct size was smaller in patients receiving intravenous metoprolol compared with controls (23.4 [SD 15.0] versus 34.0 [SD 23.7] g; adjusted difference -11.4; 95% confidence interval [CI] -18.6 to -4.3). Left ventricular ejection fraction was higher in the intravenous metoprolol group (48.1% [SD 8.4%] versus 43.1% [SD 10.2%]; adjusted difference 5.0; 95% CI 1.6 to 8.4). Metoprolol administration did not increase the incidence of the prespecified safety combined endpoint: 6.8% versus 17.8% in controls (risk difference -11.1; 95% CI -21.5 to -0.6).

CONCLUSION:

Out-of-hospital administration of intravenous metoprolol by EMS within 4.5 hours of symptom onset in our subjects reduced infarct size and improved left ventricular ejection fraction with no excess of adverse events during the first 24 hours.

• Authors: Alonso Mateos, Inés García-Lunar, José M García-Ruiz, Gonzalo Pizarro, Rodrigo Fernández-Jiménez, Pilar Huertas, Ana García-Álvarez, Leticia Fernández-Friera, Jesús Bravo, José Flores-Arias, María V Barreiro, Luisa Chayán-Zas, Ervigio Corral, Valentín Fuster, Vicente Sánchez-Brunete, Borja Ibáñez, METOCARD-CNIC Investigators
• Journal: Annals of emergency medicine (Ann Emerg Med) Vol. 65 Issue 3 Pg. 318-24 (Mar 2015) ISSN: 1097-6760 [Electronic] United States
• PMID: 25129820 (Publication Type: Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

Chemical References

• Adrenergic beta-1 Receptor Antagonists
• Metoprolol

Topics

• Adrenergic beta-1 Receptor Antagonists (administration & dosage, adverse effects, therapeutic use)
• Emergency Medical Services (methods)
• Female
• Humans
• Injections, Intravenous
• Male
• Metoprolol (administration & dosage, adverse effects, therapeutic use)
• Middle Aged
• Myocardial Infarction (drug therapy)
• Stroke Volume (drug effects)
• Treatment Outcome