Three-Dimensional Hemodynamics in the Human Pulmonary Arteries Under Resting and Exercise Conditions

Abstract

The biomechanical forces associated with blood flow have been shown to play a role in pulmonary vascular cell health and disease. Therefore, the quantification of human pulmonary artery hemodynamic conditions under resting and exercise states can be useful in investigating the physiology of disease development and treatment outcomes. In this study, a combined magnetic resonance imaging and computational fluid dynamics approach was used to quantify pulsatile flow fields, wall shear stress (WSS), oscillations in WSS (OSI), and energy efficiency in six subject-specific models of the human pulmonary vasculature with high spatial and temporal resolution. Averaging over all subjects, WSS was found to increase from 19.8±4.0 to 51.8±6.7 dynes/cm2, and OSI was found to decrease from 0.094±0.016 to 0.081±0.015 in the proximal pulmonary arteries between rest and exercise conditions (p<0.05). These findings demonstrate the localized, biomechanical effects of exercise. Furthermore, an average decrease of 10% in energy efficiency was noted between rest and exercise. These data indicate the amount of energy dissipation that typically occurs with exercise and may be useful in future surgical planning applications.

Quantitative characterization of postnatal growth trends in proximal pulmonary arteries in rats by phase-contrast magnetic resonance imaging

“…We have shown with PCMRI that the average right-left lung flow split is 68:32 throughout development. This is in accord with data from humans that show no significant differences in flow split between children and adults: 56:43 and 53:47, respectively (8), and an average of 54:46 in 21-to 51-yr-old adults (29). The left lung in humans thus receives a higher percentage of the CO than the left lung in rats.…”

Quantifying turbulent wall shear stress in a subject specific human aorta using large eddy simulation

“…An inverse relation between <OSI> and <TAWSS> is also seen, with low values of <OSI> corresponding to high <TAWSS> which is in line with findings from other studies e.g. [26,27]. As the oscillating shear variable is insensitive to However, there were, interestingly a few points that departed from the inverse relationship and exhibited elevated values for both parameters, indicated by the dotted box.…”

The Role of Wall Shear Stress in the Assessment of Right Ventricle Hydraulic Workload

“…21 Previous studies have utilized computational modeling to show that the pulmonary vasculature is exposed to varying wall shear stress (WSS) in resting and exercise conditions. 22 Computational simulations of the pulmonary vasculature have been used to predict treatment reactivity 23,24 and for surgical planning, 24 in addition to generally suggesting that WSS could play an important role in PH disease progression. 23,25 Computational models 26 and direct processing of phase-contrast MRI (PC-MRI) velocity data 27,28 have revealed a WSS decrease in the general PH population but have stopped short of directly linking decreased WSS to disease outcome.…”