Relationship between right heart catheterization and exercise testing in heart failure patients with and without pulmonary hypertension - cross-sectional study.

Introduction: Left-sided heart disease is the leading cause of pulmonary hypertension (PH). Right heart catheterization (RHC) is the gold standard for diagnosing PH, although it is invasive. Noninvasive cardiopulmonary exercise testing (CPET) could potentially help select heart failure (HF) patients who require RHC. Objectives: The study aimed to assess whether CPET could predict PH in patients with HF. Patients and methods: In this prospective cohort study, we analyzed data from 428 HF patients with a median age of 55 years and reduced left ventricular ejection fraction (≤40%) who underwent both RHC and CPET. Patients with acute clinical instability or precapillary PH were excluded. Results: The median LVEF was 20%, and 66.8% of patients were in NYHA class III or IV. PH was diagnosed by RHC in 76.9% of patients. Breathing reserve was lower and peak respiratory exchange ratio was higher in patients with PH. Patients with pulmonary vascular resistance (PVR) > 3 WU and mean pulmonary artery pressure >40 mmHg had lower indexed peak oxygen uptake and higher VE/VCO2. Indexed peak oxygen uptake improved the prediction of PH with PVR > 3 WU when added to the model composed of clinical and laboratory parameters. Conclusions: No differences were observed in indexed peak oxygen uptake or VE/VCO₂ slope between patients with and without PH. However, CPET results allowed more accurate prediction of more severe PH phenotypes. Patients with PH had lower ejection fraction and worse NYHA functional class and were more likely to be male and to have chronic kidney disease and diabetes. Overall, CPET parameters correlated with RHC findings and may help identify HF patients with PH, especially with high pulmonary vascular resistance. However, CPET cannot replace invasive hemodynamic assessment by RHC.