Prognostic Value of Cardiopulmonary Exercise Testing Parameters in Young Heart Failure Patients with Moderately Reduced Exercise Capacity

Background: Exercise capacity, evaluated using cardiopulmonary exercise testing (CPET), is an important prognostic factor in ambulatory heart failure (HF) patients.However, interpreting the results of CPET in young, ambulatory HF patients who tend to J o u r n a l P r e -p r o o f be optimistic about their prognosis is complicated.This study aimed to assess the clinical impact of CPET parameters in predicting the prognosis of young, ambulatory HF patients.Methods: This single-center retrospective observational study targeted young (<50 years) HF patients with reduced ejection fraction (left ventricular ejection fraction <40%) and peak oxygen uptake (VO2) >12 mL/kg/min.The primary endpoint was occurrence of major adverse cardiovascular events (MACE), such as death, admission for HF, and fatal arrhythmia, within 1 year after CPET.Results: A total of 113 patients (median age, 43 [35-47] years) were enrolled: of these, 45 (39.8%) experienced MACE (death, n = 2; admission for HF, n = 35; fatal arrhythmia, n = 8).Multivariate Cox regression analysis demonstrated age, plasma brain natriuretic peptide level, serum creatinine level, and ventilatory efficiency (VE/VCO2 slope) were associated with the occurrence of MACE within 1 year after CPET.Receiver operating characteristic curve analysis revealed a VE/VCO2 slope of 31 was the optimal cutoff value for predicting prognosis.Conclusions: Nearly 40% of young (<50 years) HF patients with moderately reduced exercise capacity (peak VO2 >12 mL/kg/min) experienced MACE within 1 year after CPET.Among these patients, those with a VE/VCO2 slope >31 may warrant earlier consideration for left ventricular assist devices or heart transplantation.