Mortality Risk and Beta-Blockers Post-ACS: Impact of LV Function
WASHINGTON, DC—In patients with preserved left ventricular (LV) function post-acute coronary syndrome (ACS), beta-blocker usage was found to be associated with an unexpected increase in all-cause mortality after adjusting for important baseline covariates. Findings from this study, led by Ahmed Abdi Ali from University of Calgary, Calgary, Canada, were presented at the ACC.17 Scientific Session.
While the benefits of beta-blocker use in managing patients with heart failure and LV systolic dysfunction has been established, what is less clear is their role in patients following ACS with normal LV function and "without a history of heart failure, recurrent ischemia, or arrhythmia," Ali explained. Study authors aimed to evaluate the association between beta-blocker use and all-cause mortality in patients presenting with ACS based on the presence or absence of significant LV dysfunction.
A total of 2,181 patients who had undergone invasive coronary angiography and cardiac magnetic resonance (CMR) imaging were included; CMR was used to assess LV volumes, mass, and LV ejection fraction (LVEF). They were then categorized based on the presence of moderate-severe LV dysfunction, which was defined as LVEF <50%.
For patients with significant LV dysfunction (n=467) LVEF was 24.5% compared to 53.7% in those without significant LV dysfunction (n=1,714). Mean LVEDVI was 150.8mL/m2 vs. 91.mL/m2 and mean LVMassi was 93.8g/m2 vs. 72.8g/m2, respectively. During a follow-up of median 2.8 years, there were 179 deaths, of which 80 were from the LV dysfunction group.
The multivariate analysis, which accounted for comorbidities, extent of coronary artery disease, and other medications use, showed that patients with LV dysfunction who used beta-blockers post-ACS had a 40% reduction in all-cause mortality (hazard ratio [HR] 0.60, 95% CI: 0.36–0.98; P=0.04). But patients with preserved LVEF who used beta-blockers showed a significant increase in all-cause mortality (adjusted HR 1.65, 95% CI: 1.02–2.71; P=0.04).
"Among patients undergoing angiography for ACS and CMR imaging, beta blocker usage was associated with reduced mortality in those with LV dysfunction," stated Ali. "However, we found an elevation in mortality among those with preserved LV function."