RESEARCH ARTICLE


Influence of Oscillating Flow on LDL Transport and Wall Shear Stress in the Normal Aortic Arch



J Soulis1 , *, G Giannoglou2, M Dimitrakopoulou 1, V Papaioannou1, S Logothetides3, D Mikhailidis4
1 Fluid Mechanics, School of Engineering, Demokrition University of Thrace, Xanthi, Greece
2 AHEPA University General Hospital, 1st Cardiology Department, Aristotle University of Thessaloniki, Thessaloniki, Greece
3 AHEPA Physics Department, Aristotle University of Thessaloniki, Thessaloniki, Greece
4 Dept. of Clinical Biochemistry (Vascular Prevention Clinics) and Dept. of Surgery, Royal Free Hospital campus, University College Medical School, University College London, London, UK


© Soulis et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Fluid Mechanics, School of Engineering, Demokrition University of Thrace, 67100 Xanthi, Greece; Tel: ++302541079617; Fax: ++302310994838; E-mail:jvsoulis@med.auth.gr


Abstract

Lipid accumulation in the aortic wall is an important factor in the development of atherosclerosis. The Low Density Lipoprotein (LDL) at the surface of the endothelium in relation to Wall Shear Stress (WSS) in the normal human aortic arch under unsteady, normal flow and mass conditions was computationally analysed. Concave sides of the aortic arch exhibit, relatively to the convex ones, elevated LDL levels at the surface of the endothelium for all time steps. At the peak systolic velocity, the LDL level reaches a value 23.0% higher than that at entrance in the ascending-descending aorta region. The corresponding LDL levels at the surface of the endothelium for the near minimum entrance velocity instant reaches 26.0%. During the cardiac cycle, the highest area averaged normalized LDL taken up as compared to the lowest one is 0.69%. WSS plays an important role in the lipid accumulation. Low WSS regions are exposed to high LDL levels at the surface of the endothelium. Regions of elevated LDL levels do not necessarily co-locate to the sites of lowest WSS. The near wall paths of the velocities might be the most important factor for the elevated LDL levels at the surface of the endothelium.

Keywords: Unsteady Low-density lipoprotein Transport, Wall Shear Stress, Atherosclerosis, Aortic Arch..