Echocardiographic versus invasive hemodynamic assessment in pulmonary arterial hypertension: correlation, agreement, and insights into right ventricle –pulmonary arterial coupling

Background Accurate assessment of pulmonary hemodynamics and right ventricular function is central to the management of pulmonary arterial hypertension (PAH). While echocardiography is widely used for its noninvasive evaluation, its agreement with invasive measurements and its ability to reflect right ventricle pulmonary arterial coupling remain areas of ongoing investigation. The aim of this study is to evaluate the correlation and agreement between transthoracic echocardiography (TTE) and pulmonary artery catheterization (PAC) derived hemodynamics and to explore the clinical relevance of right ventricle pulmonary arterial coupling indices in PAH. Methods Cross sectional observational study; patients with PAH underwent TTE and PAC within a short time interval were included. Echocardiographic parameters PAP, RAP and area, TAPSE, RVFAC, and derived indices; TAPSE/PASP and RVFAC/PASP. These were compared with invasive hemodynamic measurements, including PAPs, cardiac index, PVRI, PAC, and SvO2. Association and agreement between variables were evaluated. Results Twenty- nine patients with a mean age of 44 ± 15 years; only 4 (16%) patients are males. The mean BMI is 27 ± 6 kg/m2 and the mean BSA is 1.70 ± 0.2 m², TTE and PAC measurements show insignificant differences between of PASP (78.21 ± 24.95 vs. 78.31 ± 28.99 mmHg; p = 0.979), nor for PAMP or PADP. Echocardiographic PASP and PAMP demonstrate significant correlations with invasive measurements ( r = 0.693 and r = 0.632, respectively; p < 0.001), whereas PADP show a weaker correlation ( r = 0.350, p = 0.05). Bland–Altman analysis reveals small biases but wide limits of agreement, RV functional indices are significantly associated with invasive hemodynamics. RVFAC correlated with pulmonary pressures and cardiac index, while both TAPSE/PASP and RVFAC/PASP demonstrate significant relationships with PVRI, PAC, exercise capacity, and SvO2. Conclusions Echocardiography provides a reasonable noninvasive approximation of pulmonary hemodynamics; however, agreement with invasive measurements remains limited. Integration of echocardiographic RV functional and RV–pulmonary arterial coupling indices with invasive hemodynamic assessment may provide a more comprehensive evaluation of disease severity in PAH.