Prognostic significance of mid-range ejection fraction following acute coronary syndrome (ANZACS-QI 23).

Abstract

<h4>Aim</h4>Recommendations regarding medication use after acute coronary syndrome (ACS) are dichotomised according to whether left ventricular ejection fraction (LVEF) is <40% or ≥40%. In the context of heart failure (HF), a mid-range EF (mrEF, 40-49%) confers an intermediate prognosis between reduced EF (rEF, <40%) and preserved EF (pEF, ≥50%). The aim of this study was to describe, in the context of ACS, the frequency of each EF subgroup and their associated outcomes.<h4>Methods</h4>Consecutive patients presenting with ACS who underwent coronary angiography during 2015 were enrolled in the ANZACS-QI (All New Zealand Acute Coronary Syndrome-Quality Improvement) registry. Outcomes were obtained using anonymised linkage to national datasets. Cox proportional hazards models were used to adjust for confounding variables.<h4>Results</h4>Of the cohort of 6,216 patients, 31% did not have an LVEF assessment. Of those with a recorded LVEF, 63% had pEF, 21% had mrEF and 16% had rEF. Mean follow-up was 1.5 years. After adjusting for age, sex, clinical risk factors and post-ACS management, those with mrEF and rEF had a higher adjusted risk of all-cause mortality compared to pEF (HR 1.55, 95% CI 1.12-2.15 and HR 2.57, 95% CI 1.89-3.48, respectively). After adjustment, rEF was associated with an increased risk of subsequent HF hospitalisation (HR 2.32, 95% CI 1.75-3.08).<h4>Conclusions</h4>One in five patients post-ACS have mrEF, which is associated with an intermediate risk of morbidity and mortality compared to those with pEF and rEF. Further study is warranted to determine the optimal management for these patients.