title: Variables Measured During Cardiopulmonary Exercise Testing as Predictors of Mortality in Chronic Systolic Heart Failure.
abstract: BACKGROUND
  Data from a cardiopulmonary exercise (CPX) test are used to determine prognosis in patients with chronic heart failure (HF). However, few published studies have simultaneously compared the relative prognostic strength of multiple CPX variables.
  
  
  OBJECTIVE
  The study sought to describe the strength of the association among variables measured during a CPX test and all-cause mortality in patients with HF with reduced ejection fraction (HFrEF), including the influence of sex and patient effort, as measured by respiratory exchange ratio (RER).
  
  
  METHODS
  Among patients (n = 2,100, 29% women) enrolled in the HF-ACTION (HF-A Controlled Trial Investigating Outcomes of exercise traiNing) trial, 10 CPX test variables measured at baseline (e.g., peak oxygen uptake [Vo2], exercise duration, percent predicted peak Vo2 [%ppVo2], ventilatory efficiency) were examined.
  
  
  RESULTS
  Over a median follow-up of 32 months, there were 357 deaths. All CPX variables, except RER, were related to all-cause mortality (all p < 0.0001). Both %ppVo2 and exercise duration were equally able to predict (Wald chi-square: ∼141) and discriminate (c-index: 0.69) mortality. Peak Vo2 (ml·kg(-1)·min(-1)) was the strongest predictor of mortality among men (Wald chi-square: 129) and exercise duration among women (Wald chi-square: 41). Multivariable analyses showed that %ppVo2, exercise duration, and peak Vo2 (ml·kg(-1)·min(-1)) were similarly able to predict and discriminate mortality. In men, a 10% 1-year mortality rate corresponded to a peak Vo2 of 10.9 ml·kg(-1)·min(-1) versus 5.3 ml·kg(-1)·min(-1) in women.
  
  
  CONCLUSIONS
  Peak Vo2, exercise duration, and % ppVo2 carried the strongest ability to predict and discriminate the likelihood of death in patients with HFrEF. The prognosis associated with a given peak Vo2 differed by sex. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure; NCT00047437).
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan. Electronic address: Sketeyi1@hfhs.org.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Keteyian
authors.affiliation: Division of Cardiology, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Mahesh
authors.initials: M
authors.lastname: Patel
authors.affiliation: Division of Cardiology, Duke University School of Medicine, Durham, North Carolina.
authors.forename: William E
authors.initials: WE
authors.lastname: Kraus
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Clinton A
authors.initials: CA
authors.lastname: Brawner
authors.affiliation: Department of Exercise Science, Bloomsburg University, Bloomsburg, Pennsylvania.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: McConnell
authors.affiliation: Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York.
authors.forename: Ileana L
authors.initials: IL
authors.lastname: Piña
authors.affiliation: Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Leifer
authors.affiliation: Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
authors.forename: Jerome L
authors.initials: JL
authors.lastname: Fleg
authors.affiliation: Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Gordon
authors.initials: G
authors.lastname: Blackburn
authors.affiliation: Ahmanson-UCLA Cardiomyopathy Center, Ronald Regan-UCLA Medical Center, Los Angeles, California.
authors.forename: Gregg C
authors.initials: GC
authors.lastname: Fonarow
authors.affiliation: Division of Cardiology, Cone Health, Greensboro, North Carolina.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Chase
authors.affiliation: Division of Cardiology, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Lucy
authors.initials: L
authors.lastname: Piner
authors.affiliation: University Hospitals Case Medical Center, Cleveland, Ohio.
authors.forename: Marianne
authors.initials: M
authors.lastname: Vest
authors.affiliation: Division of Cardiology, Duke University School of Medicine, Durham, North Carolina.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: O'Connor
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Ehrman
authors.affiliation: St. Vincent Heart Center of Indiana, Indianapolis, Indiana.
authors.forename: Mary N
authors.initials: MN
authors.lastname: Walsh
authors.affiliation: Division of Cardiology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Gregory
authors.initials: G
authors.lastname: Ewald
authors.affiliation: Division of Cardiology, Cone Health, Greensboro, North Carolina.
authors.forename: Dan
authors.initials: D
authors.lastname: Bensimhon
authors.affiliation: Division of Cardiology, Johns Hopkins Hospital, Baltimore, Maryland.
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Russell
mesh_terms: D000328:Adult; D000368:Aged; D002423:Cause of Death / Q000639:trends; D018450:Disease Progression; D005080:Exercise Test / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D054143:Heart Failure, Systolic / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D011237:Predictive Value of Tests; D011379:Prognosis; D013318:Stroke Volume / Q000502:physiology*; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D014481:United States / Q000453:epidemiology
keywords: peak Vo(2); respiratory exchange ratio; sex; survival