Beta Blocker Therapy Improves 3-Year Outcomes Following Primary PCI for Acute MI

A study published in the Journal of Cardiology found a clinical benefit for beta blocker therapy following primary percutaneous coronary intervention (PCI) among patients with acute myocardial infarction (AMI) with non-reduced left ventricular ejection fraction (REF).

The Japanese registry of acute Myocardial Infarction diagnosed by Universal dEfiniTion (J-MINUET) study was a prospective multicenter study conducted at 28 sites in Japan between 2012 and 2014. Patients who received primary PCI following non-REF AMI were evaluated for clinical outcomes on the basis of receiving beta blocker therapy. Non-REF was defined as left ventricular ejection fraction (LVEF) of 40% or greater.

The beta-blocker (n=1353) and no beta-blocker (n=570) cohorts comprised 77.0% and 75.8% men, aged mean 67.0±12.1 and 68.6±12.3 years (P =.007), 67.7% and 61.1% had hypertension (P =.006), 55.5% and 47.9% had dyslipidemia (P =.002), LVEF was 55.6%±9.1% and 59.1%±9.0% (P <.001), and mean heart rate was 77.6±20.0 and 73.5±18.5 bpm (P <.001), respectively.

Fewer of the beta-blocker recipients had a radial PCI approach (29.6% vs 41.8%; P <.001), more had a left anterior descending artery lesion (50.5% vs 36.3%; P <.001), multi-vessel disease (42.6% vs 37.2%; P =.029), and an initial thrombolysis in MI flow of 0 to 1 (65.8% vs 60.0%; P =.015), and they had shorter door to device time (median, 70 vs 80 min; P =.003) compared with the no beta-blocker group, respectively.

At discharge, more of the beta-blocker cohort also received anti-platelet therapy, dual anti-platelet therapy, renin-angiotensin-system (RAS) blocker, and statins compared with patient who did not receive beta blocker therapy (all P <.001).

At 3 years, fewer beta blocker therapy recipients had the primary composite outcome of all-cause mortality, non-fatal MI, and non-fatal stroke (7.3% vs 11.9%; P =.001) or the secondary composite outcome of all-cause mortality, non-fatal MI, non-fatal stroke, and heart failure hospitalization (10.1% vs 13.9%; P =.018). Stratified by event, the beta-blocker cohort had fewer all-cause mortality (3.5% vs 6.0%; P =.009) and non-fatal stroke (2.5% vs 4.2%; P =.047) events compared with the non-beta-blocker group, respectively.

Risk for the primary composite outcome was associated with age (hazard ratio [HR], 1.03; 95% CI, 1.01-1.04; P <.001), LVEF (HR, 0.98; 95% CI, 0.96-1.00; P =.033), ST-elevated MI (HR, 0.70; 95% CI, 0.49-1.00; P =.048), beta-blocker at discharge (HR, 0.66; 95% CI, 0.47-0.94; P =.021), and RAS-blocker at discharge (HR, 0.61; 95% CI, 0.42-0.89; P =.012).

In the subgroup analysis, beta-blockers were favored for preventing the primary composite outcome among all patients (HR, 0.662; 95% CI, 0.469-0.939), patients aged 68 years or older (HR, 0.634; 95% CI, 0.408-0.993), and patients with ejection fraction of 50% or greater (HR, 0.631; 95% CI, 0.424-0.942).

The major limitation of this study is that distribution of beta-blockers is not randomized.

These data indicate that patients who receive beta-blockers following primary PCI for non-REF AMI are likely to have superior clinical outcomes at 3 years.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.