title: The Added Value of Exercise Variables in Heart Failure Prognosis.
abstract: BACKGROUND
  Diminished 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.
  
  
  RESULTS
  This 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).
  
  
  CONCLUSIONS
  Peak VO2, OUES, and VE/VCO2 are independent predictors of HF prognosis over recognized clinical variables. However, no single exercise variable was superior.
authors: Division of Cardiology and Heart Transplant, Toronto General Hospital, Toronto, Ontario, Canada. Electronic address: carolina.alba@uhn.ca.
authors: Ana Carolina
authors: AC
authors: Alba
authors: Division of Cardiology and Heart Transplant, Toronto General Hospital, Toronto, Ontario, Canada.
authors: Matthew W
authors: MW
authors: Adamson
authors: Division of Cardiology and Heart Transplant, Toronto General Hospital, Toronto, Ontario, Canada.
authors: J
authors: J
authors: MacIsaac
authors: Division of Cardiology and Heart Transplant, Toronto General Hospital, Toronto, Ontario, Canada.
authors: Spencer D
authors: SD
authors: Lalonde
authors: Division of Cardiology and Heart Transplant, Toronto General Hospital, Toronto, Ontario, Canada.
authors: Wai S
authors: WS
authors: Chan
authors: Division of Cardiology and Heart Transplant, Toronto General Hospital, Toronto, Ontario, Canada.
authors: Diego Hernan
authors: DH
authors: Delgado
authors: Division of Cardiology and Heart Transplant, Toronto General Hospital, Toronto, Ontario, Canada.
authors: Heather Joan
authors: HJ
authors: Ross
mesh_terms: D000328:Adult; D002908:Chronic Disease; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies
keywords: Peak oxygen consumption; exercise; mortality; oxygen uptake efficiency slope; prognosis