Evaluating the Long-Term Impact of Early Metoprolol Treatment in STEMI

Early treatment with metoprolol was associated with improved long-term outcomes in patients with ST-segment elevation myocardial infarction (STEMI), according to study results published in The American Journal of Cardiology.

In this study (Effect of Metoprolol in Cardioprotection During an Acute Myocardial Infarction; ClinicalTrials.gov Identifier: NCT01311700), 270 patients with first anterior STEMI were randomly assigned to receive 15 mg intravenous metoprolol (n=139) or conventional STEMI therapy (n=214). The study’s primary outcome of interest was the occurrence of major adverse cardiac events (MACE; a composite of death, rehospitalization for heart failure, reinfarction, and malignant ventricular arrhythmias) at 5 years. Feature-tracking cardiovascular magnetic resonance was performed for 215 patients at 1 week post-STEMI to assess left ventricular global circumferential strain (GCS) and longitudinal strain (GLS).

At the 5 year follow-up, 17.8% of patients presented with major cardiac events. Patients who received metoprolol vs standard therapy had fewer cumulative cardiac events (hazard ratio [HR], 0.500; 95% CI, 0.277-0.903; P =.022) and admissions for heart failure (HR, 0.298; 95% CI, 0.096-0.924; P =.036).

To explore the effects of metoprolol on left ventricular features, patients were divided into groups based on GCS and GLS values and treatment group. Participants in the group with impaired left ventricular strain (ie, GCS ≥-13.1 or GLS ≥-11.5%) who received standard therapy had the greatest rate of MACE. Patients with impaired GLS who received metoprolol vs conventional STEMI therapy were 64% less likely to experience MACE (HR, 0.356; 95% CI, 0.129-0.979; P =.045).

The investigators noted that the limited number of MACE that occurred during the study period made multivariate testing challenging, particularly in subgroup analyses.

“[E]arly intravenous metoprolol has a long-term beneficial prognostic effect, particularly in patients who were at a greater risk for the occurrence of MACE due to severely impaired [left ventricular] systolic function,” the study authors concluded. “Moreover, global [left ventricular] strain assessment with feature-tracking [cardiovascular magnetic resonance] early after primary [percutaneous coronary intervention] provides important information in risk stratification of [patients with] STEMI.”

Disclosures: Several authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of disclosures.

Reference

Podlesnikar T, Pizarro G, Fernández-Jiménez R, et al. Five-year outcomes and prognostic value of feature-tracking cardiovascular magnetic resonance in patients receiving early pre-reperfusion metoprolol in acute myocardial infarction [published online July 28, 2020]. The American Journal of Cardiology. doi:10.1016/j.amjcard.2020.07.037