Simulating Multi-Scale Pulmonary Vascular Function by Coupling Computational Fluid Dynamics With an Anatomic Network Model

Abstract

The function of the pulmonary circulation is truly multi-scale, with blood transported through vessels from centimeter to micron scale. There are scale-dependent mechanisms that govern the flow in the pulmonary vascular system. However, very few computational models of pulmonary hemodynamics capture the physics of pulmonary perfusion across the spatial scales of functional importance in the lung. Here we present a multi-scale model that incorporates the 3-dimensional (3D) complexities of pulmonary blood flow in the major vessels, coupled to an anatomically-based vascular network model incorporating the multiple contributing factors to capillary perfusion, including gravity. Using the model we demonstrate how we can predict the impact of vascular remodeling and occlusion on both macro-scale functional drivers (flow distribution between lungs, and wall shear stress) and micro-scale contributors to gas exchange. The model predicts interactions between 3D and 1D models that lead to a redistribution of blood between postures, both on a macro- and a micro-scale. This allows us to estimate the effect of posture on left and right pulmonary artery wall shear stress, with predictions varying by 0.75–1.35 dyne/cm2 between postures.

Inference of alveolar capillary network connectivity from blood flow dynamics

“…The work of Zurita and Hurtado (2022) has predicted the 3D spatial distribution of blood flow and gas exchange. Multi-scale models (Clark et al, 2010, 2011; Clark and Tawhai, 2018; Ebrahimi et al, 2022) are more complex and allow to investigate even broader relationships. They enable predictions of both whole lung function with alterations in small vascular structures and small-scale vascular function in response to impairment of the proximal pulmonary artery.…”

“…The work of Zurita and Hurtado (2022) has predicted the 3D spatial distribution of blood flow and gas exchange. Multi-scale models (Clark et al, 2010(Clark et al, , 2011Clark and Tawhai, 2018;Ebrahimi et al, 2022) are more complex and allow to investigate even broader relationships. They enable predictions of both whole lung function with alterations in small vascular structures and small-scale vascular The novelty in our approach is that we exploit the interdependence of structure and function in the opposite direction: On the basis of physiological blood flow parameters, we evaluated the realism of systematically introduced morphological variations.…”