The relationship between left ventricular ejection fraction and mortality in patients with acute heart failure: insights from the ASCEND-HF Trial

Abstract

Aim: Acute decompensated heart failure (ADHF) is associated with significant morbidity and mortality but the relationship between LVEF and outcomes is unclear. We explored the association between LVEF and 30 and 180 day mortality in 7007 ADHF patients enrolled in the Acute Studies of Nesiritide in Decompensated Heart Failure (ASCEND-HF) trial.

Methods and results: We explored the association between LVEF and 30 and 180 day mortality in 7007 ADHF patients enrolled in the Acute Studies of Nesiritide in Decompensated Heart Failure (ASCEND-HF) trial. LVEF was analysed both as a continuous variable and according to three categories: < 40% (LowEF), 40-50% [intermediate EF (IntEF)], and > 50% [preserved ejection fraction (PresEF)]. Of the patients in the trial, 4474 (78.7%) had LowEF, 674 (11.9%) had IntEF, and 539 (9.5%) had PresEF. The unadjusted 30 and 180 day mortality was similar for LowEF (3.7%, 12.3%), IntEF (3.4%, 13.1%), and PresEF (4.3%, 14.1%), respectively (P > 0.05). After multivariable adjustment, the hazard ratio (HR) for 180 day mortality remained similar for the LowEF [HR 0.96, 95% confidence interval (CI) 0.75-1.24; P = 0.77] and IntEF (0.91, 95% CI 0.66-1.3; P = 0.58) compared to PresEF patients. By contrast, when LVEF was evaluated as a continuous measure, it exhibited a U-shaped pattern with mortality. After matching for age and sex, the mortality risk attributed to LVEF was attenuated, as the LVEF increased as a continuous variable over 35%. However, in patients with EF < 35%, the mortality risk continue to increase as the LVEF declined.

Conclusions: Among patients with ADHF, the unadjusted mortality rates are similar across LVEF strata. However, after accounting for key patient variables, the mortality risk increases as EF falls below 35%. These data will be useful in planning future studies of ADHF.

Clinical trial registration: www.clinicaltrials.gov identifier: NCT00475852.

Keywords: Acute heart failure; Clinical trial; Ejection fraction; Outcomes.