Impact of time past exercise testing on prognostic variables in heart failure.
BACKGROUND
Cardiopulmonary exercise testing (CPET) is considered a standard of care in heart failure (HF). The impact that duration of time post-evaluation has on the prognostic value of CPET, however, has not been explored. The purpose of this investigation was to examine the ability of peak oxygen consumption (VO(2)) and the minute ventilation-carbon dioxide production (VE/VCO(2)) slope to predict cardiac-related events at different time intervals post CPET.


METHODS
Two hundred fifty-eight subjects diagnosed with HF underwent CPET. The ability of peak VO(2) and VE/VCO(2) slope to predict cardiac-related events without a time limit, one year post CPET and greater than one year post CPET was examined.


RESULTS
Both peak VO(2) and VE/VCO(2) slope were significant predictors of cardiac-related mortality and hospitalization during the no time constraint and one year post CPET tracking scenarios (Hazard Ratio Range: 3.5-12.4, p<0.001). Peak VO(2) was no longer a significant predictor of mortality greater than one year post CPET. Generally, as time following CPET surpassed one year, the prognostic sensitivity of both variables slightly increased ( approximately 5%) while specificity sharply decreased ( approximately 20%).


CONCLUSIONS
Both peak VO(2) and VE/VCO(2) slope are significant predictors of cardiac-related events in HF. However, the prognostic characteristics of these variables following CPET appear to be time-sensitive.
Arena
Ross
R
Department of Physical Therapy, Box 980224, Virginia Commonwealth University, Medical College of Virginia, Health Sciences Campus, Richmond, VA 23298-0224, USA.
Myers
Jonathan
J
Aslam
Syed Salman
SS
Varughese
Elsa B
EB
Peberdy
Mary Ann
MA
D002245:Carbon Dioxide / Q000378:metabolism; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011659:Pulmonary Gas Exchange; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013997:Time Factors
D002245:Carbon Dioxide