EARLY Beta-Blocker Administration Before Primary PCI in STEMI - EARLY-BAMI
The goal of the trial was to assess the safety and efficacy of early administration of intravenous (IV) metoprolol in patients presenting with ST-elevation myocardial infarction (STEMI) and scheduled for primary percutaneous coronary intervention (PCI).
Contribution to the Literature: The EARLY-BAMI trial showed that early routine administration of IV metoprolol is not beneficial in reducing infarct size in patients presenting with STEMI and undergoing primary PCI.
Patients were randomized in a 1:1 fashion to receive IV bolus metoprolol 5 mg (n = 336) or matching placebo (n = 347). Two bolus doses were given: the first one in the ambulance, and second at the PCI hospital at the catheterization laboratory before the PCI procedure only if systolic blood pressure (BP) was >100 mm Hg and heart rate was >60 bpm.
- Total number of enrollees: 683
- Duration of follow-up: 30 days
- Mean patient age: 62 years
- Percentage female: 25%
Other salient features/characteristics:
- Diabetes: 16%
- Beta-blocker use at home prior to MI: 19%
- Anterior STEMI: 51%
- Early presentation within 6 hours: 92%
- Mean systolic BP/diastolic BP at admission: 137.6/82.5 mm Hg
- Mean heart rate at admission: 76.5 bpm
- Multivessel disease: 44%
- Patients aged >18 years with symptoms of acute STEMI for >30 minutes but <12 hours
- Confirmed diagnosis of STEMI with plan for primary PCI
- Killip class III and IV
- Systolic BP <100 mm Hg
- Heart rate <60 bpm
- Type II and III atrioventricular (AV) block
- History of previous MI
- Known asthma, pacemaker, or implantable cardioverter-defibrillator
- Pregnancy or breast-feeding
Primary endpoint, infarct size on delayed enhancement cardiac magnetic resonance (CMR) at 30 days, for metoprolol vs. placebo: 15.3% vs. 14.9%, p = 0.61
Secondary outcomes (for metoprolol vs. placebo):
- Left ventricular ejection fraction on CMR: 51% vs. 51.7%, p = 0.68
- Severe bradycardia: 1.5% vs. 0.6%, p = 0.28
- Cardiogenic shock: 0.6% vs. 0.3%, p = 0.62
- Ventricular arrhythmia in acute phase: 3.6% vs. 6.9%, p = 0.05
- Thirty-day major adverse cardiac events: 6.2% vs. 6.9%, p = 0.72
The results of this trial indicate that early routine administration of IV metoprolol is not beneficial in reducing infarct size in patients presenting with STEMI and undergoing primary PCI. Patients in cardiogenic shock or at high risk were excluded, as were patients with advanced AV blocks. There was no clear safety signal with early administration of IV beta-blockers, as noted in the larger COMMIT CC2 trial. Another smaller trial, METOCARD-CNIC, had observed a potential benefit in patients with anterior STEMI, but was not noted on subgroup analysis in this trial.
One limitation of this trial is that the sample size that had the primary endpoint assessed on CMR was significantly smaller (~45% lower). This likely reduced overall power. Patients who did not undergo CMR were significantly sicker than patients who did.
Roolvink V, Ibanez B, Ottervanger JP, et al. Early Administration of Intravenous Beta-Blockers in Patients With ST-Elevation Myocardial Infarction Before Primary PCI. J Am Coll Cardiol 2016;67:2705-15.
Editorial: Newby LK. Intravenous Beta-Blockers for Cardioprotection in STEMI: The Saga Continues. J Am Coll Cardiol 2016;67:2716-18.
Presented by Dr. Vincent Roolvink at the American College of Cardiology Annual Scientific Session, Chicago, IL, April 3, 2016.
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