Calculating Wall Shear Stress in Infant Pulmonary Veins

Background: The mechanism of pediatric intraluminal pulmonary vein stenosis (PVS) remains unknown. It is hypothesized that elevated wall shear stress (WSS) as a result of excessive pulmonary blood flow (left to right shunts) and/or pulmonary vein distortion from surrounding anatomy contributes to the neo-intimal proliferation. Calculating WSS in pediatric pulmonary veins using ferumoxytol enhanced cardiac magnetic resonance (FcMRI) has not been reported and would represent a novel method of evaluation. Objectives: The primary objective is to determine the feasibility of calculating WSS in infant pulmonary veins using FcMRI. The secondary objective is to determine the magnitude and variability of WSS in pulmonary veins among high-risk patients and normal controls. Study Design: Prospective, interventional, single center, feasibility study Setting/Participants: Single center study at The Children's Hospital of Philadelphia. High-risk infants (n = 10) will include two groups of patients; (1) infants with moderate to severe bronchopulmonary dysplasia (BPD) and (2) infants with postoperative repair of total anomalous pulmonary venous connection (TAPVC). Group 1 participants will be infants who are undergoing an MRI as part of clinical care for other issues (i.e., MRI brain for hypoxic ischemia encephalopathy), with the research FcMRI being performed following the clinical care MRI. Group 2 participants will be infants who are undergoing FcMRI as part of clinical care. Controls (n = 10) will be pediatric patients without intracardiac defects who are undergoing FcMRI as part of clinical care (i.e., evaluation of anomalous coronary, aortopathy, vascular ring). Study Procedures, Interventions and Measures: Participants will undergo FcMRI and have the WSS calculated in each pulmonary vein (right upper, right lower, left upper, left lower) using several methodologies. Patients will be followed for 12 months following cMRI monitoring for a new diagnosis of PVS.