Simulation of Competitive Flow in the Coronary Arteries Bypass

Azimi Nejad, Milad | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50602 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Firoozabadi, Bahar
  7. Abstract:
  8. Atherosclerosis is one of the most important factors for mortality and morbidity in the world. Coronary artery bypass graft (CABG) is applied for treatment of this disease which in this surgery, the patient vessels, such as internal thoracic artery and saphenous vein, are harvested and grafted to the coronary arteries. The graft success and its performance in short and long-term are depended on the much factors e.g. the severity of stenosis in the coronary artery. It should be noted that the low level of stenosis in the coronary artery causes the creation of undesirable phenomenon of competitive flow in the grafts after the surgery which this phenomenon has been reported as a cause of graft restenosis in the early days after the surgery. So in this work, the simulation and modeling of this phenomenon are conducted and with the aid of this model, the comparison of the aforementioned vessels from the viewpoint of graft patency and restenosis in short and long-term is numerically performable. Moreover, the patient status such as smoking, gender, aging, Anemia and Polycythemia disease are simulated. The achieved results show that smoking and Polycythemia increases the probability of stenosis and thrombosis in the graft, respectively and anemia has a strong effect on the graft long-term patency. The blood flow interaction with the vessel wall and heart myocardial movement decreases the risk parameters of graft stenosis, while were added to the computational model. To this end, the 0D modified Windkessel boundary condition, Newtonian and Carreau non-Newtonian models to simulate viscose properties of blood, 5–Parameter Mooney-Rivlin Model for modeling of the hyperelastic property of vessel wall were applied. Finally, the hemodynamic parameters of blood flow such as wall shear stress (WSS), oscillatory shear index (OSI) and relative residence time (RRT) were chosen for evaluating the graft stenosis and its patency in short and long-term
  9. Keywords:
  10. Atherosclerosis ; Artery Stenosis ; Coronary Artery Bypass ; Coronary Arteries Disease (CAD) ; Competitive Flow ; Five Parameter Mooney-Rivlin Model ; Carreau Non-Newtonian Model

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