title: Comprehensive analysis of cardiopulmonary exercise testing and mortality in patients with systolic heart failure: the Henry Ford Hospital cardiopulmonary exercise testing (FIT-CPX) project.
abstract: BACKGROUND
  Many studies have shown a strong association between numerous variables from a cardiopulmonary exercise (CPX) test and prognosis in patients with heart failure with reduced ejection fraction (HFrEF). However, few studies have compared the prognostic value of a majority of these variables simultaneously, so controversy remains regarding optimal interpretation.
  
  
  RESULTS
  This was a retrospective analysis of patients with HFrEF (n = 1,201; age = 55 ± 13 y; 33% female) and a CPX test from 1997 to 2010. Thirty variables from a CPX test were considered in separate adjusted Cox regression analyses to describe the strength of the relation of each to a composite end point of all-cause mortality, left ventricular assist device implantation, or heart transplantation. During a median follow-up of 3.8 years, there were 577 (48.0%) events. The majority of variables were highly significant (P < .001). Among these, percentage of predicted maximum V˙O2 (ppMV˙O2; Wald = 203; P < .001; C-index = 0.73) was similar to VE-VCO2 slope (Wald = 201; P < .001; C = 0.72) and peak V˙O2 (Wald = 161; P < .001; C = 0.72). In addition, there was no significant interaction observed for peak respiratory exchange ratio <1 vs ≥1.
  
  
  CONCLUSIONS
  Consistent with prior studies, many CPX test variables were strongly associated with prognosis in patients with HFrEF. The choice of which variable to use is up to the clinician. Renewed attention should be given to ppMV˙O2, which appears to be highly predictive of survival in these patients.
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan. Electronic address: cbrawne1@hfhs.org.
authors.forename: Clinton A
authors.initials: CA
authors.lastname: Brawner
authors.affiliation: Saint Luke's Mid America Heart Institute, Kansas City, Missouri.
authors.forename: Ali
authors.initials: A
authors.lastname: Shafiq
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Aldred
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Ehrman
authors.affiliation: Office of Biostatistics Research, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Leifer
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Yelena
authors.initials: Y
authors.lastname: Selektor
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Cristina
authors.initials: C
authors.lastname: Tita
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Velez
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Celeste T
authors.initials: CT
authors.lastname: Williams
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: John R
authors.initials: JR
authors.lastname: Schairer
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: David E
authors.initials: DE
authors.lastname: Lanfear
authors.affiliation: Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, Michigan.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Keteyian
mesh_terms: D002423:Cause of Death / Q000639:trends; D015444:Exercise / Q000523:psychology*; 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; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013318:Stroke Volume; D015996:Survival Rate / Q000639:trends; D014481:United States / Q000453:epidemiology
keywords: Cardiomyopathy; exercise test; prognosis; survival