Cardiopulmonary exercise testing reflects similar pathophysiology and disease severity in heart failure patients with...

We are unaware of any previous investigation that has compared the relationship of key cardiopulmonary exercise testing (CPX) variables to various measures of pathophysiology between heart failure-reduced ejection fraction (HFrEF) and HF-preserved ejection fraction (HFpEF) cohorts that are well matched with respect to baseline characteristics and their exercise response, which is the purpose of the present study.

Thirty-four patients with HFpEF were randomly matched to 34 subjects with HFrEF according to age and sex as well as peak oxygen consumption (VO2), ventilatory efficiency (VE/VCO2 slope), and exercise oscillatory ventilation (EOV). In addition to CPX, patients also underwent echocardiography with tissue Doppler imaging (TDI) and assessment of N-terminal pro-B-type natriuretic peptide (NT-proBNP).

When matched for age, sex, and CPX variables, the HFrEF and HFpEF cohorts had similar echocardiography with TDI and NT-proBNP values, indicating comparable disease severity. In addition, the correlations between key CPX measures (peak VO2 and VE/VCO2 slope) and echocardiography with TDI and NT-proBNP measures were similar between HFrEF and HFpEF groups. Of note, the correlation between the VE/VCO2 slope and pulmonary artery systolic pressure and NT-proBNP was highly significant in both groups (r ≥ 0.65, p < 0.01). Moreover, subjects with EOV in both groups had a significantly higher PASP (∼47 vs. ∼35 mmHg, p < 0.05).

The results of the current study indicate CPX equally represents disease severity in HFrEF and HFpEF patients. This is a novel finding supporting the key role of CPX in the clinical follow-up of HF patients irrespective of LVEF and cardiac phenotype.