Early-BAMI: Early use of beta-blockers does not benefit patients with STEMI before PCI

CHICAGO — Using IV beta blockers before PCI in patients with STEMI was safe but provided no benefit, researchers reported at the American College of Cardiology Scientific Session.

In 683 patients with STEMI and Killip Class I or II without atrioventricular block presenting less than 12 hours after onset, the researchers assessed whether administering IV beta-blockers would reduce infarct size and improve clinical outcomes.

Patients in the Early-BAMI study (mean age, 62 years; 75% men) were randomly assigned to receive two vials of metoprolol 5 mg or matched placebo. The first bolus was given in the ambulance. If systolic BP was > 100 mm Hg and heart rate was > 60 bpm, the second bolus was given in the cath lab.

The primary endpoint was infarct size as assessed by MRI at 30 days; 54.8% of patients received an MRI. Secondary endpoints included enzymatic infarct size and secondary arrhythmias. There were also safety endpoints of cardiogenic shock, symptomatic bradycardia and symptomatic hypotension.

The results were simultaneously published in the Journal of the American College of Cardiology.

Vincent Roolvink, MD, from Isala Klinieken, Zwolle, Netherlands, said during a presentation that infarct size as a percentage of left ventricle on MRI did not differ between the groups at 30 days (metoprolol group, 15.3%; placebo group, 14.9%; P = .616).

Vincent Roolvink

Enzymatic infarct size also did not differ (P = .88), nor did left ventricular ejection fraction (P = .68), adverse events or peak or area under the creatinine kinase curve, he said.

However, metoprolol was associated with a lower rate of malignant arrhythmias (3.6% vs. 6.9%; P = .05), according to the researchers.

The results conflict with the METOCARD-CNIC trial, which was not placebo-controlled, Roolvink said, noting that the other trial was limited to patients with anterior infarcts only, used a higher dose of metoprolol and had a longer time between metoprolol administration and PCI.

“More large randomized trials are needed whether early beta-blockers have any effect in STEMI patients treated with primary PCI,” he said. “The safety profile, low cost and reduction of acute malignant arrhythmias encourage the performance of additional large trials.”

In an accompanying editorial in JACC, L. Kristin Newby, MD, MHS, from Duke University Medical Center, wrote that additional trials in the mode of Early-BAMI and METOCARD-CNIC are unlikely to resolve the issue because of challenges such as slow enrollment, cost and many patients not getting an MRI, and “would likely be insufficient to affect change in practice even if consistent results on infarct size reduction were to be achieved.”

L. Kristin Newby

Newby, a member of the Cardiology Today Editorial Board, wrote that “a more reasonable approach may be to conduct a definitive trial stratified by STEMI location and adequately powered for clinical outcomes, including death, recurrent [MI], and [HF] events.” – by Erik Swain

Reference s :

Roolvink V, et al. Joint ACC/TCT Late-Breaking Clinical Trials. Presented at: American College of Cardiology Scientific Session; April 2-4, 2016; Chicago.

Newby LK. J Am Coll Cardiol. 2016;doi:10.1016/j.jacc.2016.03.532.

Roolvink V, et al. J Am Coll Cardiol. 2016;doi:10.1016/j.jacc.2016.03.522.

Disclosure: The study was funded in part by an unrestricted grant from Medtronic. The researchers report no relevant financial disclosures. Newby reports financial ties with various pharmaceutical and medical device companies.