Large eddy simulation of LDL surface concentration in a subject specific human aorta

• Published in: Journal of biomechanics Vol. 45; no. 3; pp. 537 - 542
• Main Authors: Lantz, Jonas, Karlsson, Matts
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 02.02.2012; Elsevier; Elsevier Limited
• Subjects: Accumulation; Aorta; Aorta - metabolism; Aorta - pathology; Atherosclerosis; Atherosclerosis (general aspects, experimental research); Atherosclerosis - physiopathology; Biological and medical sciences; Blood and lymphatic vessels; Blood flow; Blood Flow Velocity - physiology; Cardiology. Vascular system; Computer Simulation; Computerized, statistical medical data processing and models in biomedicine; Coronary vessels; Correlation; Diastole; Disturbed flow; Geometry; Human; Humans; Large eddy simulation; Lipoproteins, LDL - chemistry; Low-density lipoprotein; Magnetic resonance imaging; Medical sciences; Models and simulation; Models, Cardiovascular; Permeability; Physical Medicine and Rehabilitation; Physiology; Reynolds number; Stress concentration; Stress, Mechanical; Turbulence models; Veins & arteries; Velocity; Wall shear stress; Low-density lipoprotein; Wall shear stress; Atherosclerosis; Disturbed flow; Human; Pathogenesis; Cardiovascular disease; Modeling; Artery; Vascular disease; Biomechanics; Lipoprotein LDL; Large eddy simulation; Mechanical stress; Blood vessel; Shear stress; Aorta; Circulatory system; Vascular wall; Biomedical engineering
• DOI: 10.1016/j.jbiomech.2011.11.039
• ISSN: 0021-9290; 1873-2380

The development of atherosclerosis is correlated to the accumulation of lipids in the arterial wall, which, in turn, may be caused by the build-up of low-density lipoproteins (LDL) on the arterial surface. The goal of this study was to model blood flow within a subject specific human aorta, and to study how the LDL surface concentration changed during a cardiac cycle. With measured velocity profiles as boundary conditions, a scale-resolving technique (large eddy simulation, LES) was used to compute the pulsatile blood flow that was in the transitional regime. The relationship between wall shear stress (WSS) and LDL surface concentration was investigated, and it was found that the accumulation of LDL correlated well with WSS. In general, regions of low WSS corresponded to regions of increased LDL concentration and vice versa. The instantaneous LDL values changed significantly during a cardiac cycle; during systole the surface concentration was low due to increased convective fluid transport, while in diastole there was an increased accumulation of LDL on the surface. Therefore, the near-wall velocity was investigated at four representative locations, and it was concluded that in regions with disturbed flow the LDL concentration had significant temporal changes, indicating that LDL accumulation is sensitive to not only the WSS but also near-wall flow.