Right Ventricular Remodeling Using Three-Dimensional Echocardiography in Pediatric Pulmonary Arterial Hypertension Associated with Congenital Heart Disease: A Case–Control Study

Background: Three-dimensional echocardiography (3DE) enables comprehensive assessment of right ventricular (RV) remodeling, but its role in children with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD) remains incompletely characterized. Methods: In the current case–control study, eleven children with catheterization-confirmed PAH-CHD and 50 healthy controls underwent conventional, three-dimensional, and speckle-tracking echocardiography. Three-dimensional RV geometry and function were compared between groups, and their discriminative performance and relationships with conventional and deformation indices were evaluated. Results: Children with PAH-CHD showed increased RV volumes and transverse dimensions, reduced longitudinal dimension, and impaired systolic function compared with controls (all adjusted p < 0.05). RV fractional area change (RV_FAC_3D) and RV ejection fraction (RV_EF_3D) measured by 3DE demonstrated acceptable-to-good discriminative performance (AUC = 0.88, 95% CI: [0.73,1] and AUC = 0.85, 95% CI: [0.70,1], respectively), whereas 3D tricuspid annular plane systolic excursion (RV_TAPSE_3D) and RV_SV_3D did not achieve significant discrimination after correction for multiple comparisons. After controlling for PAH-CHD duration, significant partial Pearson correlations were observed between RV end-systolic volume (RV_ESV_3D) and left ventricular end-diastolic mass (LV_ED_mass_3D): partial r = 0.85, p = 0.0017, p-corrected = 0.012, LV_ED_mass_3D: RV_SV_3D and RV_Ld_3D were both negatively correlated with LV_AIS (partial r = −0.81, p = 0.0042 and partial r = −0.85, p = 0.0016, respectively p-corrected = 0.0352). Conclusions: Most 3D indices discriminated PAH-CHD from controls with acceptable-to-good accuracy. RV volumetric and functional indices correlated broadly with conventional 2D and diastolic Doppler parameters, with LV geometry and segmental mechanics, and, more selectively, with right atrial contractile strain although not all correlations remained significant after correction for multiple comparison. These exploratory findings suggest that 3DE may complement conventional echocardiography in the multiparametric assessment of pediatric PAH-CHD.