The minute ventilation/carbon dioxide production slope is prognostically superior to the oxygen uptake efficiency slope.
BACKGROUND
Ventilatory efficiency, commonly assessed by the minute ventilation (VE)-carbon dioxide production (VCO2) slope, has proven to be a strong prognostic marker in the heart failure (HF) population. Recently, the oxygen uptake efficiency slope (OUES) has demonstrated prognostic value, but additional comparisons to established cardiopulmonary exercise test (CPET) variables are required.


RESULTS
A total of 341 subjects were diagnosed with HF participated in this analysis. The VE/VCO2 slope and the OUES were calculated using 50% (VE/VCO2 slope(50) or OUES(50)) and 100% (VE/VCO2 slope(100) or OUES(100)) of the exercise data. Peak oxygen consumption (VO2) was also determined. There were 47 major cardiac-related events during the 3-year tracking period. Receiver operating characteristic (ROC) curve analysis demonstrated the classification schemes for both VE/VCO2 slope and OUES calculations as well as peak VO2 were statistically significant (all areas under the ROC curve: > or = 0.74, P < .001). Area under the ROC curve for the VE/VCO2 slope(100) was, however, significantly greater than OUES(50), OUES(100), and peak VO2 (P < .05).


CONCLUSIONS
Although the OUES was a significant predictor of mortality, the VE/VCO2 slope maintained optimal prognostic value. An elevated VE/VCO2 slope may be the single best indicator of increased risk for adverse events.
Arena
Ross
R
Department of Physical Therapy, Virginia Commonwealth University, Health Sciences Campus, Richmond, Virginia 23298-0224, USA.
Myers
Jonathan
J
Hsu
Leon
L
Peberdy
Mary Ann
MA
Pinkstaff
Sherry
S
Bensimhon
Daniel
D
Chase
Paul
P
Vicenzi
Marco
M
Guazzi
Marco
M
D015415:Biomarkers / Q000378:metabolism; D001944:Breath Tests; D002245:Carbon Dioxide / Q000378:metabolism*; D005080:Exercise Test; D045853:Exhalation / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000378:metabolism* / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D012307:Risk Factors; D015996:Survival Rate
D015415:Biomarkers; D002245:Carbon Dioxide