Key result
Pre-reperfusion IV metoprolol in anterior STEMI improves 6-month LVEF by ~3.5% and reduces HF admissions.
Why the study?
Early IV metoprolol reduces infarct size in STEMI with pPCI, but its long-term effects on LV function and clinical events were unknown.
Does early pre-reperfusion IV metoprolol improve long-term LVEF and reduce clinical events in patients with anterior STEMI undergoing pPCI?
RCT (n=270)
Does early pre-reperfusion IV metoprolol improve long-term LVEF and reduce clinical events in patients with anterior STEMI undergoing pPCI?
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“Infarct size was 20% smaller in the IV metoprolol recipients. This finding was encouraging because infarct size is a major determinant of long-term morbidity and mortality. And while primary PCI for STEMI results in very low acute mortality, there is a high residual risk of subsequent heart failure and death. So the search is on for treatments that reduce infarct size.”
“Instead, these data provide a solid basis for further investigation of intravenous beta blockers and should stimulate the performance of dedicated randomized trials powered for hard clinical endpoints so that we may more fully know the role of an old therapy in the contemporary era of reperfusion with primary PCI.”
“Here, we show that an inexpensive medication already approved for STEMI treatment (intravenous metoprolol) can significantly reduce infarct size simply by being administered before reperfusion.”
Early pre-reperfusion IV metoprolol in anterior STEMI patients undergoing pPCI improves long-term LVEF and reduces heart failure admissions.
The goal of this trial was to study the long-term effects of intravenous (IV) metoprolol administration before reperfusion on left ventricular (LV) function and clinical events. Early IV metoprolol during ST-segment elevation myocardial infarction (STEMI) has been shown to reduce infarct size when used in conjunction with primary percutaneous coronary intervention (pPCI). The METOCARD-CNIC (Effect of Metoprolol in Cardioprotection During an Acute Myocardial Infarction) trial recruited 270 patients with Killip class ≤II anterior STEMI presenting early after symptom onset (<6 h) and randomized them to pre-reperfusion IV metoprolol or control group. Long-term magnetic resonance imaging (MRI) was performed on 202 patients (101 per group) 6 months after STEMI. Patients had a minimal 12-month clinical follow-up. Left ventricular ejection fraction (LVEF) at the 6 months MRI was higher after IV metoprolol (48.7 ± 9.9% vs. 45.0 ± 11.7% in control subjects; adjusted treatment effect 3.49%; 95% confidence interval [CI]: 0.44% to 6.55%; p = 0.025). The occurrence of severely depressed LVEF (≤35%) at 6 months was significantly lower in patients treated with IV metoprolol (11% vs. 27%, p = 0.006). The proportion of patients fulfilling Class I indications for an implantable cardioverter-defibrillator (ICD) was significantly lower in the IV metoprolol group (7% vs. 20%, p = 0.012). At a median follow-up of 2 years, occurrence of the pre-specified composite of death, heart failure admission, reinfarction, and malignant arrhythmias was 10.8% in the IV metoprolol group versus 18.3% in the control group, adjusted hazard ratio (HR): 0.55; 95% CI: 0.26 to 1.04; p = 0.065. Heart failure admission was significantly lower in the IV metoprolol group (HR: 0.32; 95% CI: 0.015 to 0.95; p = 0.046). In patients with anterior Killip class ≤II STEMI undergoing pPCI, early IV metoprolol before reperfusion resulted in higher long-term LVEF, reduced incidence of severe LV systolic dysfunction and ICD indications, and fewer heart failure admissions.
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Pizarro et al. (2014) conducted an RCT in Acute Myocardial Infarction (n=270). Intravenous metoprolol vs. Control was evaluated on Left ventricular ejection fraction (LVEF) at 6 months (adjusted treatment effect 3.49%, 95% CI 0.44 to 6.55, p=0.025). Early intravenous metoprolol before reperfusion in anterior STEMI resulted in higher LVEF at 6 months (48.7% vs 45.0%; P=0.025) and fewer heart failure admissions.
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