Computational Fluid Dynamics-Based Stratification of Morbidity Risks in Hypoplastic Pulmonary Anatomy

Numerous attempts have been made to assess morbidity and mortality risks in conditions that create hypoplastic pulmonary arteries such as congenital diaphragmatic hernia (CDH) and congenital pulmonary airway malformation. Previous studies have utilized proxy measures, like the lung-to-head ratio and liver position, to assess pulmonary hypoplasia. However, these convenient but simplified metrics are inherently limited in providing a comprehensive description of lung vasculature and corresponding function [1]. Perinatal MRI-calculated lung volumes are sometimes used, but mainly for general predictions of postnatal survival and morbidity risks.

This study employs computational fluid dynamics (CFD) comprehensively characterize and stratify neonatal pulmonary vasculature. Neonate MRIs were reconstructed using 3D Slicer, and time of flight MRI data stacks were selectively filtered to isolate arterial structures. CFD was implemented using Star CCM+ to determine vascular wall resistance, utilizing approximated pressure gradients, velocities, and pulsatile flow rates as boundary conditions. Moreover, this model possesses significant prognostic utility as CFD-calculated pulmonary resistance enables the calculation of optimal blood viscosity as a function of hematocrit concentration, maximizing pulmonary flow and subsequent systemic oxygen delivery. By leveraging CFD, this study demonstrates a a more complete understanding of the intricate dynamics within the pulmonary system and provides improved risk assessment and treatment planning for neonates diagnosed with CDH.

1. 1) Yamoto M, Tanaka Y, Fukumoto K, Miyake H, Nakajima H, Koyama M, Mitsushita N, Nii M, Kawahara H, Urushihara N. Cardiac fetal ultrasonographic parameters for predicting outcomes of isolated left-sided congenital diaphragmatic hernia. J Pediatr Surg. 2015 Dec;50(12):2019-24. doi: 10.1016/j.jpedsurg.2015.08.016. Epub 2015 Aug 28.