title: Prognostic impact of the addition of peak oxygen consumption to the Seattle Heart Failure Model in a transplant referral population.
abstract: BACKGROUND
  In this study we investigated whether the addition of peak oxygen consumption (VO(2)) improves the predictive accuracy of the Seattle Heart Failure Model (SHFM). The SHFM is a validated multivariate risk model that uses NYHA classification to assess functional capacity rather than peak oxygen consumption (VO(2)).
  
  
  METHODS
  Outpatients (n = 1,240) evaluated for transplant at three centers had their SHFM score calculated and peak VO(2) measured. The outcomes assessed were death/LVAD/urgent transplant with censoring at the time of elective transplant.
  
  
  RESULTS
  Over the course of 4.0 (mean) years of observation, there were 571 events. Both the SHFM score (χ(2) = 227) and peak VO(2) (χ(2) = 88, both p < 0.0001) were highly predictive of outcomes. The SHFM and peak VO(2) were modestly correlated (r = 0.39, p < 0.0001). In a multivariate Cox model, peak VO(2) added to the SHFM with a hazard ratio of 0.949 (p < 0.0001) for each 1-ml/kg/min increase. Peak VO(2) improved both the net reclassification improvement and integrated discrimination index (both p ≤ 0.0002). Peak VO(2) provided additive prognostic information within each SHFM score (p < 0.05). The 1-year areas under the receiver-operating characteristic curve were obtained for peak VO(2) (0.645, 95% CI 0.606 to 0.684), SHFM (0.758, 95% CI 0.721 to 0.795) and SHFM with peak VO(2) (0.766, 95% CI 0.731 to 0.802). The SHFM-predicted vs actual survival free of LVAD/UNOS Status 1 transplant at 1 year (86% vs 83%) and 4 years (63% vs 63%) were similar.
  
  
  CONCLUSIONS
  The multivariate SHFM is a powerful predictor of death/LVAD/urgent transplant. Peak VO(2) adds prognostic information across the spectrum of the SHFM, but changes in decision regarding transplant listing occur mainly in moderate-risk patients.
authors: Division of Cardiology, University of Washington,1959 NE Pacific Street, Seattle, WA 98195, USA. levywc@uw.edu
authors: Wayne C
authors: WC
authors: Levy
authors: Keith D
authors: KD
authors: Aaronson
authors: Todd F
authors: TF
authors: Dardas
authors: Paula
authors: P
authors: Williams
authors: Jennifer
authors: J
authors: Haythe
authors: Donna
authors: D
authors: Mancini
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D016027:Heart Transplantation; D006353:Heart-Assist Devices; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015999:Multivariate Analysis; D010101:Oxygen Consumption / Q000502:physiology*; D011237:Predictive Value of Tests; D011379:Prognosis; D012017:Referral and Consultation; D012720:Severity of Illness Index; D015996:Survival Rate; D014861:Washington