Right ventricular-pulmonary arterial coupling in patients with different etiologies of pulmonary arterial hypertension evaluated by three-dimensional echocardiography

Abstract

Right ventricular-pulmonary arterial (RV-PA) coupling is closely associated with risk stratification and clinical prognosis in patients with pulmonary arterial hypertension (PAH). However, comparative studies investigating RV-PA coupling profiles across different etiologies of PAH remain limited. Three-dimensional echocardiography (3DE) permits comprehensive and accurate evaluation of right ventricular (RV) function, offering a reliable noninvasive method for assessing RV-PA coupling. To characterize RV-PA coupling using 3DE in PAH patients of different etiologies and to investigate its clinical correlations. Seventy adult patients with PAH and 27 age- and sex-matched healthy controls underwent echocardiographic examination. Conventional parameters including tricuspid annular plane systolic excursion (TAPSE), tricuspid annular peak systolic velocity (S’), fractional area change (FAC), and pulmonary arterial systolic pressure (PASP) were measured. RV global and regional (inflow, body, outflow) end-diastolic volume (EDV) and ejection fraction (EF) were determined by 3DE. Plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) was measured in PAH patients. Mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance (PVR) were obtained by right heart catheterization. Patients were stratified by etiology into Group A (n = 44, congenital heart disease-associated PAH) and Group B (n = 26, idiopathic PAH). Adequate image quality for 3DE analysis was obtained in 93% of acquisitions. Compared with controls, PAH patients exhibited significantly increased global and regional RV EDV and decreased EF (all P < 0.001). There were no significant between-group differences in global/regional RV EDV, S’, MPAP, or PVR. Group B demonstrated significantly lower EF/PASP, FAC/PASP, TAPSE/PASP, and S’/PASP ratios, as well as higher NT-proBNP levels, than Group A (all P < 0.05). In the overall PAH cohort, all RV-PA coupling ratios were inversely correlated with MPAP (r = -0.481 to -0.635, all P < 0.05) and PVR (r = -0.400 to -0.660, all P < 0.05). In Group B, global RV EF/PASP, inflow RV EF/PASP, FAC/PASP, TAPSE/PASP, and S’/PASP ratios were inversely correlated with log₂NT-proBNP (r = -0.476 to -0.593, all P < 0.05). RV-PA coupling characteristics differ according to PAH etiology. At similar levels of RV afterload, RV-PA coupling is better preserved in patients with congenital heart disease-associated PAH than in those with idiopathic PAH. In PAH without intracardiac shunts, 3DE-derived RV-PA coupling indices are inversely correlated with PVR and NT-proBNP, and may serve as valuable noninvasive markers for risk stratification and disease monitoring.