The Added Value of Exercise Variables in Heart Failure Prognosis

Abstract

IntroductionDiminished exercise capacity is a key symptom in heart failure (HF). Exercise predictors (peak VO2, VE/VCO2 slope, and oxygen uptake efficiency slope [OUES]) are prognostic markers but studied in isolation. We evaluated if these exercise variables offer additional prognostic value to clinical predictors in HF. Methods and ResultsThis was a single-institution retrospective cohort study of 517 consecutive HF patients. We used Cox proportional hazards modeling to determine the additional prognostic value of exercise variables on mortality, HF hospital admissions, and a composite outcome of ventricular assistance device (VAD) implantation, heart transplantation (HT), and death. During a mean follow-up of 2.7 years, 52 deaths, 47 HTs, and 19 VAD implantations occurred. After adjusting for age, New York Heart Association functional class, ejection fraction, body mass index, creatinine, and B-type natriuretic peptide, peak VO2 (hazard ratio [HR] 0.91, 95% confidence interval [CI] 0.85–0.96), OUES (HR 0.92, 95% CI 0.87–0.97), and VE/VCO2 (HR 1.03, 95% CI 1.01–1.05) were independent predictors of the composite outcome. Similar discriminatory capacity existed between the exercise variables (c-statistics 0.77, 0.78, and 0.78, respectively). Only VE/VCO2 was an independent predictor of admissions (HR 1.04, 95% CI 1.01–1.07), and only peak VO2 was an independent predictor of mortality (HR 0.90, 95% CI 0.84–0.98). ConclusionsPeak VO2, OUES, and VE/VCO2 are independent predictors of HF prognosis over recognized clinical variables. However, no single exercise variable was superior.