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·kg− 1·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·kg− 1·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.