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Multiscale Modeling of Coronary Blood Flow and Effects on Endothelial Cells

Pakravan, Hossein Ali | 2016

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 48269 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Saeedi, Mohammad Saeed; Firoozabadi, Bahar
  7. Abstract:
  8. Atherosclerosis in coronary arteries is one of the most important topics due to its high prevalence and the importance of these arteries for supplying blood to the heart. The morphology of endothelial cells (ECs) is an independent index for determining the atheroprone sites. The ECs show a regular elongated and aligned configuration to the blood flow, at the atheroprotected regions; on the other hand, at the atheroprone regions, the cells have a polygonal, randomly oriented morphology. The thesis intended to propose a method for coronary artery simulation, which is able to determine the atheroprone sites regarding the ECs morphology. In addition, the attempts were made to investigate the effects of different mechanical stimuli factors on the disease. For these purposes, a multisclae simulation was performed including the artery scale and cell scale. To determine the mechanical stimuli of ECs including wall shear stress and arterial wall strains, the artery scale was performed using Fluid-Structure Interaction (FSI) simulation, considering the dynamic curvature of coronary artery due to the heartbeat. In the cell scale, an inventive cell model was developed, which is able to determine the morphology of ECs for the given mechanical stimuli from the artery scale. The results of ECs morphology were reported as graphical illustrations of cell population as well as quantitative parameters such as average shape index (SI), orientation angle (OA) and their standard deviations as a measure for SI and OA irregularities or dispersions in the cell population. The results indicate that the dynamic curvature is an undesirable factor for atherosclerosis. Therefore, it is speculated that the locating of coronary arteries on myocardial wall and the dynamic curvature due to the heartbeat is one of the factors for high prevalence of atherosclerosis in these arteries. Moreover, the results demonstrate that the elongation and regular orientation of ECs increase with pulse pressure (especially with decrease in diastolic pressure) and cause a decrease in atherosclerosis risk. In addition, the variation of describing factors for ECs morphology with average wall shear stress, the direction of imposed wall shear stress and the strains in different directions was reported and discussed
  9. Keywords:
  10. Coronary Artery ; Atherosclerosis ; Cell Modeling ; Endothelial Cell ; Multi-Scale Simulation ; Fluid-Structure Interaction

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