Comparison of ventilatory expired gas parameters used to predict hospitalization in patients with heart failure.

BACKGROUND: Several ventilatory expired gas measures obtained during exercise testing demonstrate prognostic value in the heart failure (HF) population. Comparison of prognostic efficacy between pertinent measures is sparse.

METHODS: The ability of various expressions of peak oxygen consumption (VO2), the relationship between minute ventilation (VE) and carbon dioxide production (VCO2), and the partial pressure of end-tidal carbon dioxide (P(ET)CO2) were assessed to determine which measure(s) best predicted cardiac-related hospitalization over a 1-year period in subjects diagnosed with HF.

RESULTS: Univariate Cox regression analysis found that several expressions of peak VO 2, VE-VCO2 relationship, and P(ET)CO2 were significant predictors of hospitalization. Multivariate Cox regression analysis revealed that the VE/VCO2 slope significantly predicted hospitalization (chi2 = 29.1, P <.00001). Peak VO 2 and P(ET)CO2 did not provide additional predictive value.

CONCLUSIONS: The prognostic superiority of the VE/VCO2 slope over peak VO2 may be a result of the latter measure's partial dependence on subject effort and skeletal muscle function.