Combining peak oxygen consumption and ventilatory efficiency in the prognostic assessment of patients with heart failure.
Exercise ventilatory efficiency (VE/VCO2 slope) and peak oxygen consumption (VO2) are strong mortality predictors in patients with heart failure and we combined these 2 variables' beta coefficients from Cox regression to investigate a new prognostic index. Average follow-up was 3.8+/-1.8 years for 355 patients (72% male, 51+/-10 years). The beta coefficients from peak VO2 (17.3+/-5.0 ml x kg(-1) x min(-1)) and VE/VCO2 slope (37.0+/-9.0) constructed an exercise index defined as one half the peak VO2 subtracted from one fifth of the VE/VCO2 slope. The mean index was -1.14+/-3.79 and a more positive index was always associated with a higher probability of death. Patients with extremely poor prognoses were identified equally well by the index and by individual thresholds for peak VO2 (<14 ml x kg(-1) x min(-1)) and of VE/VCO2 slope (>40). In conclusion, the index did not add additional prognostic information in this cohort but it did display the prognostic superiority of VE/VCO2 slope.
Bard
Robert L
RL
Gillespie
Brenda W
BW
Clarke
Nicholas S
NS
Nicklas
John M
JM
D005260:Female; D006333:Heart Failure / Q000378:metabolism* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011379:Prognosis; D015656:Respiratory Mechanics