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 (Vimage2), the relationship between minute ventilation (VE) and carbon dioxide production (Vimage2), and the partial pressure of end-tidal carbon dioxide (PETimage2) 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 Vimage2, VE-Vimage2 relationship, and PETimage2 were significant predictors of hospitalization. Multivariate Cox regression analysis revealed that the VE/Vimage2 slope significantly predicted hospitalization (χ2 = 29.1, P < .00001). Peak Vimage2 and PETimage2 did not provide additional predictive value. Conclusions The prognostic superiority of the VE/Vimage2 slope over peak Vimage2 may be a result of the latter measureʹs partial dependence on subject effort and skeletal muscle function. (Am Heart J 2002;143:427-32.)