Differences in pulmonary arterial flow hemodynamics between children and adults with pulmonary arterial hypertension as assessed by 4D-flow CMR studies

Despite different developmental and pathologic processes affecting lung vascular remodeling in both patient populations, differences in 4D-MRI findings between children and adults with PAH have not been studied. The purpose of this study was to compare flow hemodynamic state, including flow-mediated shear forces, between pediatric and adult patients with PAH matched by severity of pulmonary vascular resistance index (PVRi). Adults (n=10) and children (n=10) with PAH matched by pulmonary vascular resistance index (PVRi), and healthy adult (n=10) and pediatric (n=10) subjects underwent comprehensive 4D-Flow MRI to assess peak systolic wall shear stress (WSSmax) measured in the main, right, and left pulmonary arteries (MPA, RPA, and LPA), viscous energy loss (EL) along the MPA-RPA and MPA-LPA tract, and qualitative analysis of secondary flow hemodynamics. WSSmax was decreased in all pulmonary vessels in children with PAH when compared to the same age group (all P < 0.05). Similarly, WSSmax was decreased in a...