The strengths and weaknesses of non-invasive parameters obtained by echocardiography and cardiopulmonary exercise testing in comparison with the hemodynamic assessment by the right heart catheterization in patients with pulmonary hypertension

Purpose: Pulmonary hypertension (PH) diagnosis requires invasive assessment by right heart catheterization (RHC), but screening and monitoring are performed using non-invasive methods: echocardiography and cardiopulmonary exercise testing (CPET). The aim of the study was to assess correlations between the parameters obtained in non-invasive testing and RHC in patients with PH of different etiologies.

Material/methods: The study included 53 medical records of PH patients (32 women) aged 29-81 years. We analyzed correlations between RHC (systolic pulmonary artery pressure (sPAP), diastolic pulmonary artery pressure (dPAP), pulmonary vascular resistance (PVR), cardiac output (CO)) and echocardiographic (tricuspid annular plane systolic excursion (TAPSE), sPAP) and CPET parameters (end-tidal oxygen and carbon dioxide pressures (PetO₂, PetCO₂), ventilation efficiency (VE/VCO₂) slope).

Results: Echocardiographic estimation correlated well with RHC measurement of sPAP (r=0.65, P<0.001). TAPSE correlated with PVR assessed with thermodilution method (r=-0.5, P=0.005), dPAP (r=-0.53, P=0.002) and CO (r=0.53, P=0.002). PVR assessed with thermodilution and Fick methods showed positive correlation with PetO₂ (r=0.74, P<0.001 and r=0.72, P<0.001) and negative correlation with PetCO₂ (r=-0.59, P=0.004 and r=-0.64, P=0.002) at the anaerobic threshold. VE/VCO₂ slope correlated with dPAP (r=0.43, P=0.04) and PVR calculated with both methods (r=0.52, P=0.01 and r=0.52, P=0.02).

Conclusions: Simple cardiac function indicators obtained by commonly used non-invasive methods allow only approximate estimation of the main hemodynamic RHC-derived parameters: sPAP, CO and PVR. Obtained results suggest the relationship between RV dysfunction and ventilation abnormalities in PH patients.