The lowest VE/VCO2 ratio during exercise as a predictor of outcomes in patients with heart failure.
BACKGROUND
The lowest minute ventilation (VE) and carbon dioxide production (VCO(2)) ratio during exercise has been suggested to be the most stable and reproducible marker of ventilatory efficiency in patients with heart failure (HF). However, the prognostic power of this index is unknown.


RESULTS
A total of 847 HF patients underwent cardiopulmonary exercise testing (CPX) and were followed for 3 years. The associations between the lowest VE/VCO(2) ratio, maximal oxygen uptake (peak VO(2)), the VE/VCO(2) slope, and major events (death or transplantation) were evaluated using proportional hazards analysis; adequacy of the predictive models was assessed using Akaike information criterion (AIC) weights. There were 147 major adverse events. In multivariate analysis, the lowest VE/VCO(2) ratio (higher ratio associated with greater risk) was similar to the VE/VCO(2) slope in predicting risk (hazard ratios [HR] per unit increment 2.0, 95% CI 1.1-3.4, and 2.2, 95% CI 1.3-3.7, respectively; P < .01), followed by peak VO(2) (HR 1.6, 95% CI 1.1-2.4, P=.01). Patients exhibiting abnormalities for all 3 responses had an 11.6-fold higher risk. The AIC weight for the 3 variables combined (0.94) was higher than any single response or any combination of 2. The model including all 3 responses remained the most powerful after adjustment for beta-blocker use, type of HF, and after applying different cut points for high risk.


CONCLUSIONS
The lowest VE/VCO(2) ratio adds to the prognostic power of conventional CPX responses in HF.
Myers
Jonathan
J
Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA. drj993@aol.com
Arena
Ross
R
Oliveira
Ricardo B
RB
Bensimhon
Daniel
D
Hsu
Leon
L
Chase
Paul
P
Guazzi
Marco
M
Brubaker
Peter
P
Moore
Brian
B
Kitzman
Dalane
D
Peberdy
Mary Ann
MA
D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000378:metabolism* / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods / Q000592:standards*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D011237:Predictive Value of Tests; D012123:Pulmonary Ventilation / Q000502:physiology*; D012129:Respiratory Function Tests; D016896:Treatment Outcome
D002245:Carbon Dioxide