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.