Right ventricular remodelling in pulmonary hypertension: quantifying function and morphology using 3D echocardiography

Abstract Introduction Pre-capillary pulmonary hypertension (PH) is a life-threatening condition caused by narrowing or obstruction of the pulmonary vasculature. These vascular changes lead to increased pulmonary vascular resistance, necessitating a compensatory rise in pulmonary arterial pressure to maintain adequate circulation of the lungs. As a result of pressure overload, the right ventricle (RV) undergoes structural and functional remodelling, which potentially results in fatal RV failure. Prediction of RV failure remains challenging, and its underlying mechanisms remain largely unknown. Therefore, studying RV remodelling patterns is essential to improve clinical decision-making and treatment planning in PH patients. Purpose To investigate the potential of 3D echocardiography (3DE) to gain insight in RV remodelling patterns in patients with pre-capillary PH. Methods A proof-of-concept study was performed using RV-focused 3DE images from 4 pre-capillary PH patients and 50 healthy controls. 3D dynamic RV meshes were generated with commercially available software (TomTec 4D RV-Function). A method was developed to decompose RV contraction in longitudinal (LT), radial (RD), and anteroposterior (AP) motion directions (Figure 1), allowing for detailed assessment of functional RV remodelling. Additionally, a novel approach was implemented to quantify regional endocardial curvature to assess morphological RV changes. Both analyses were preformed using an in-house developed software application (RV-Dynamics), and were compared between PH patients and healthy controls. Results Functional analysis revealed that RD wall motion was most impaired in PH patients, showing a reduction from 25% in healthy controls to 16%. In contrast, LT contraction remained similar between PH patients and healthy controls (20%). Morphologically, RV remodelling was most pronounced in the inferior free wall, where curvature was decreased in PH patients compared to controls. A similar reduction in curvature was observed in the interventricular septum of PH patients (Figure 2). Conclusion 3DE could be a valuable modality for quantifying both functional and morphological RV remodelling. This proof-of-concept study suggests that RV dysfunction in pre-capillary PH primarily affects radial contraction, underlining the importance of multidirectional functional assessment. The preservation of longitudinal contraction in PH patients raises concerns about the current reliance on LT-based echo parameters for RV functional evaluation. Morphological alterations were most evident in the inferior free wall and septum, emphasising the need for regional RV assessment. Further studies with larger cohorts are required for further quantification of functional and morphological RV remodelling in PH patients.Fig. 1:Axis definition and orientation Fig. 2:Regional curvature changes in PH