title: Validation of a cardiopulmonary exercise test score in heart failure.
abstract: BACKGROUND
  Cardiopulmonary exercise test (CPX) responses are strong predictors of outcomes in patients with heart failure. We recently developed a CPX score that integrated the additive prognostic information from CPX. The purpose of this study was to validate the score in a larger, independent sample of patients.
  
  
  RESULTS
  A total of 2625 patients with heart failure underwent CPX and were followed for cardiovascular (CV) mortality and major CV events (death, transplantation, left ventricular assist device implantation). Net reclassification improvement (NRI) for the score and each of its components were determined at 3 years. The VE/VCO2 slope was the strongest predictor of risk and was attributed a relative weight of 7, with weighted scores for abnormal heart rate recovery, oxygen uptake efficiency slope, end-tidal CO2 pressure, and peak VO2 having scores of 5, 3, 3, and 2, respectively. A summed score of >15 was associated with an annual mortality rate of 12.2% and a relative risk >9 for total events, whereas a score of <5 was associated with an annual mortality rate of 1.2%. The composite score was the most accurate predictor of CV events among all CPX responses considered (C indexes, 0.70 for CV mortality and 0.72 for the composite outcome). Each component of the score provided significant NRI compared with peak VO2 (category-free NRI, 0.61-0.77), and the score provided significant NRI above clinical risk factors for both CV events and mortality (NRI, 0.63 and 0.65 for CPX score compared with clinical variables alone).
  
  
  CONCLUSIONS
  These results validate the application of a simple, integrated multivariable score based on readily available CPX responses.
authors: Division of Cardiology, VA Palo Alto Healthcare System, Palo Alto, CA 94304, USA. Drj993@aol.com
authors: Jonathan
authors: J
authors: Myers
authors: Ricardo
authors: R
authors: Oliveira
authors: Frederick
authors: F
authors: Dewey
authors: Ross
authors: R
authors: Arena
authors: Marco
authors: M
authors: Guazzi
authors: Paul
authors: P
authors: Chase
authors: Daniel
authors: D
authors: Bensimhon
authors: Mary Ann
authors: MA
authors: Peberdy
authors: Euan
authors: E
authors: Ashley
authors: Erin
authors: E
authors: West
authors: Lawrence P
authors: LP
authors: Cahalin
authors: Daniel E
authors: DE
authors: Forman
mesh_terms: D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D018572:Disease-Free Survival; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D014481:United States; D016277:Ventricular Function, Left
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