Cardiopulmonary exercise testing for prognosis in chronic heart failure: continuous and independent prognostic value from VE/VCO(2)slope and peak VO(2).
BACKGROUND
Chronic heart failure carries a poor prognosis. Cardiopulmonary exercise testing is useful in predicting survival. We set out to establish the prognostic value of peak VO(2)and VE/VCO(2)slope across a range of threshold values.


RESULTS
Three hundred and three consecutive patients with stable chronic heart failure underwent cardiopulmonary exercise testing between 1992 and 1996. Their age was 59+/-11 years (mean+/-SD), peak VO(2)17. 8+/- 6.6 ml. kg(-1)min(-1), VE/VCO(2)slope 37+/-12. At the end of follow-up in January 1999, 91 patients had died (after a median of 7 months, interquartile range 3-16 months). The median follow-up for the survivors was 47 months (interquartile range 37-57 months). The areas under the receiver-operating characteristic curves for predicting mortality at 2 years were 0.77 for both peak VO(2)and VE/VCO(2)slope. With peak VO(2)and VE/VCO(2)slope viewed as continuous variables in the Cox proportional-hazards model, they were both highly significant prognostic indicators, both in univariate analysis and bivariate analysis (P<0.001 for VE/VCO(2)slope, P<0.003 for peak VO(2)).


CONCLUSIONS
Lower peak VO(2)implies poorer prognosis across a range of values from 10 to 20 ml. kg(-1)min(-1), without a unique threshold. Gradations of elevation of the VE/VCO(2)slope also carry prognostic information over a wide range (30-55). The two parameters are comparable in terms of prognostic power, and contribute complementary prognostic information.
Francis
D P
DP
National Heart & Lung Institute, Imperial College of Science, Technology and Medicine, London, U.K.
Shamim
W
W
Davies
L C
LC
Piepoli
M F
MF
Ponikowski
P
P
Anker
S D
SD
Coats
A J
AJ
D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000097:blood*; D002908:Chronic Disease; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011237:Predictive Value of Tests; D011379:Prognosis; D011659:Pulmonary Gas Exchange / Q000502:physiology; D015996:Survival Rate; D014692:Ventilation-Perfusion Ratio / Q000502:physiology
D002245:Carbon Dioxide; D010100:Oxygen