Changes in the Left Ventricular Ejection Fraction and Outcomes in Hospitalized Heart Failure Patients with Mid-range Ejection Fraction: A Prospective Observational Study

Objective Current clinical guidelines have proposed heart failure (HF) with mid-range ejection fraction (HFmrEF), defined as a left ventricular ejection fraction (LVEF) of 40-49%, but the proportion and prognosis of patients transitioning toward HF with a reduced LVEF (LVEF <40%, HFrEF) or HF with a preserved LVEF (LVEF ≥50%, HFpEF) are not fully clear. The present study prospectively evaluated the changes in the LVEF one year after discharge and the outcomes of hospitalized patients with HFmrEF. Methods We prospectively studied 259 hospitalized patients with HFmrEF who were discharged alive at our institutions between 2015 and 2019. Among them, 202 patients with HFmrEF who underwent echocardiography at the one-year follow-up were included in this study. Patient characteristics, echocardiographic data and all-cause death were collected. Results Eighty-seven (43%) patients transitioned to HFpEF (improved group), and 35 (17%) transitioned to HFrEF (worsened group). During a median follow-up of 33 months, 27 (13%) patients died. After adjustment, patients in the worsened group had an increased risk of all-cause mortality compared with those in the improved group hazard ratio 7.02, 95% confidence interval (CI) 1.13-43.48. The baseline LVEF (per 1% decrease) and tricuspid annular plane systolic excursion (per 1 mm decrease) were independent predictors of the worsened LVEF category (odds ratio 2.13, 95% CI 1.25-3.63 and odds ratio 1.31, 95% CI 1.01-1.70, respectively). Conclusion Our study showed that a worsened LVEF one year after discharge was associated with a poor prognosis in hospitalized patients with HFmrEF.