Coronary Artery Disease is the leading cause of death worldwide. CHD stems from coronary artery plaque rupture. Plaque development in coronary arteries, resulting in stenosis, causes cardiovascular events. Ruptures can occur when the coronary artery loses its durability, strength, and exceeds its stress limits. Plaque ruptures cause blood clots, resulting in acute myocardial infarction. To be able to prevent this kind of complications, this study is going to investigate the degree of stenosis effects, the number of stenosis effects, and the location of the stenosis effects by using 18 different 3D idealized models created in NX unigraphics. To understand plaque rupture, von-Mises, shear stress, and WSS (Wall Shear Stress) were investigated in these experiments. The Mooney-Rivlin (M-R) 5 parameters hyperelastic material properties are used to understand plaque behaviors and got more precise results instead of using isotropic materials. The blood flow is modeled as non-Newtonian. All models were analyzed using ANSYS software. The results show that the degree of stenosis highly impacts the stress values, and generated high numbers in terms of von-Mises stress. Also, the results show that the number of stenosis has an impact on the shear stress range, and increases stress numbers. However, there is no noticeable impact by the location of the stenosis on the stress results.
In an additional part of the study, IVUS-VH based (Intravascular Ultrasound Virtual Histology) models were created using data from 2 different phases of the cardiac cycle, as determined by the ECG (Electrocardiogram). Input parameters were the same as the ideal models, except for the inlet velocity, inlet pressure, and outlet pressure. Those pressures were set to relevant end-diastolic and end-systolic pressures, corresponding to the T-wave and R-wave models. The results clearly indicate that plaque geometry, blood flow rate, and input conditions are affecting any kinds of stress values that the study uses. After the comparison of 2 cardiac cycles, the R-wave model indicates more stress to the coronary artery.
In future work, the models will incorporate cyclic bending effects, realistic difference between 2D IVUS-VH slices instead of an assumption, pulsatile velocity effects, external heart pressure such as cardiopulmonary resuscitation (CPR) and coughing, and used 3 or 4 plaque types in the same model to gain a better understanding of coronary artery disease.
|Advisor:||Lee, Felix H., Klingensmith, Jon|
|Commitee:||Cho, Sohyung, Klingensmith, Jon, Lee, Felix H.|
|School:||Southern Illinois University at Edwardsville|
|School Location:||United States -- Illinois|
|Source:||MAI 58/06M(E), Masters Abstracts International|
|Keywords:||3d modeling, Artery disease, Coronary artery, Electrocardiogram, Intravascular ultrasound virtual histology, Stenosis|
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