Cardiopulmonary exercise testing in the clinical and prognostic assessment of diastolic heart failure

OBJECTIVES This study sought to define the relative prognostic value of cardiopulmonary exercise testing (CPET) variables in heart failure (HF) patients with preserved versus reduced systolic function. BACKGROUND Cardiopulmonary exercise testing has an established role in the assessment of patients with systolic heart failure (SHF). Two variables, peak VO2 and, more recently, the VE/VCO2 slope, have been shown to be extremely valuable in risk stratification. However, data are lacking in terms of the prognostic value of CPET in patients with diastolic heart failure (DHF). METHODS A total of 409 HF patients underwent CPET. Patients were divided into three groups according to the following left ventricular ejection fraction (LVEF) cutoffs: >= 40%, >= 45%, and >= 50%. The CPET response and the ability of peak VO2 and the VE/VCO2 slope to predict total mortality and hospitalization were examined. RESULTS At univariate Cox regression analysis, both the peak VO2 and the VE/VCO2 slope were significant predictors in SHF and DHF. Multivariate analysis documented a similar prognostic power of VE/VCO2 slope and peak VO2 in all SHF groups. Conversely, in DHF patients, VE/VCO2 slope outnumbered peak VO2, remaining the only predictor regardless of LVEF. In DHF, the area under the receiver operating characteristic curve for the VE/VCO2 slope identified a cutoff of 32.6 (74% sensitivity, 52% specificity), 33.1 (76% sensitivity, 62% specificity), and 33.3 (97% sensitivity, 40% specificity) for an LVEF cutoff of >= 40%, >= 45%, and >= 50%, respectively. CONCLUSIONS These results extend the clinical and prognostic applicability of CPET to DHF. An impairment in exercise ventilation rather than peak VO2 holds clinical and prognostic impact in this increasing subset of patients.