Non-Newtonian Endothelial Shear Stress Simulation: Does It Matter?

Frontiers in Cardiovascular Medicine

article

Vikas Thondapu¹  Daisuke Shishikura⁴  Jouke Dijkstra⁵  Shuang J. Zhu²  Eve Revalor¹  Patrick W. Serruys⁷  William J. van Gaal¹  Eric K. W. Poon¹  Andrew Ooi²  Peter Barlis¹ 

[1] Department of Medicine, Faculty of Medicine, Melbourne Medical School, Dentistry and Health Sciences, University of Melbourne;Department of Mechanical Engineering, Melbourne School of Engineering, University of Melbourne;Department of Radiology and Biomedical Imaging, Yale University School of Medicine;Department of Cardiology, Osaka Medical and Pharmaceutical University;Department of Radiology, Division of Image Processing, Leiden University Medical Center;Department of Biomedical Engineering, Melbourne School of Engineering, University of Melbourne;Department of Cardiology, National University of Ireland Galway;National Heart and Lung Institute, Imperial College London;Department of Cardiology, Northern Hospital

关键词: computational fluid dynamics;    CFD;    non-Newtonian;    rheology;    viscosity;    optical coherence tomography;    shear stress (fluid);   

DOI  :  10.3389/fcvm.2022.835270

学科分类：地球科学(综合)

来源: Frontiers

【 摘 要 】

Patient-specific coronary endothelial shear stress (ESS) calculations using Newtonian and non-Newtonian rheological models were performed to assess whether the common assumption of Newtonian blood behavior offers similar results to a more realistic but computationally expensive non-Newtonian model. 16 coronary arteries (from 16 patients) were reconstructed from optical coherence tomographic (OCT) imaging. Pulsatile CFD simulations using Newtonian and the Quemada non-Newtonian model were performed. Endothelial shear stress (ESS) and other indices were compared. Exploratory indices including local blood viscosity (LBV) were calculated from non-Newtonian simulation data. Compared to the Newtonian results, the non-Newtonian model estimates significantly higher time-averaged ESS (1.69 (IQR 1.36)Pa versus 1.28 (1.16)Pa, p < 0.001) and ESS gradient (0.90 (1.20)Pa/mm versus 0.74 (1.03)Pa/mm, p < 0.001) throughout the cardiac cycle, under-estimating the low ESS (<1Pa) area (37.20 ± 13.57% versus 50.43 ± 14.16%, 95% CI 11.28–15.18, p < 0.001). Similar results were also found in the idealized artery simulations with non-Newtonian median ESS being higher than the Newtonian median ESS (healthy segments: 0.8238Pa versus 0.6618Pa, p < 0.001 proximal; 0.8179Pa versus 0.6610Pa, p < 0.001 distal; stenotic segments: 0.8196Pa versus 0.6611Pa, p < 0.001 proximal; 0.2546Pa versus 0.2245Pa, p < 0.001 distal) On average, the non-Newtonian model has a LBV of 1.45 times above the Newtonian model with an average peak LBV of 40-fold. Non-Newtonian blood model estimates higher quantitative ESS values than the Newtonian model. Incorporation of non-Newtonian blood behavior may improve the accuracy of ESS measurements. The non-Newtonian model also allows calculation of exploratory viscosity-based hemodynamic indices, such as local blood viscosity, which may offer additional information to detect underlying atherosclerosis.

【 授权许可】

CC BY