مطالعه اثر الاستيسيته شريان بر الگوي تنش برشي ديواره و پاسخ سلول هاي اندوتليال

Study of Elasticity Effect on Wall Shear Stress Pattern and Endothelial Cells Response

Background and Objectives: In this research, effect of elasticity of arterial wall on wall shear stress waveform has been studied. This phenomenon has been considered on cardiovascular pathology using fluid and solid interaction model (FSI). Materials and Methods: The Newtonian fluid model for blood and linear elastic model for arterial wall was used. Large deformation theory has been implied to simulate arterial wall displacements. Fluid-solid interaction based transient numerical simulation have been used to consider wall displacement on model With pressure based boundary condition and Moens- Korteweg wave velocity equation, boundary condition for various elastic modulus adopted at outlet of model. Results: Results have showed the significant decreasing in mean flow rate (up to 33%) with increasing elastic modulus of vessel wall. This change is due to variation of wall distensibility with wall elasticity. Variation of flow waveform is due to change in pressure gradient waveform with wall elasticity. Results showed that the significant changes in wall shear stress waveform. These changes have been included both decreasing of maximum wall shear stress and generating of negative wall shear stress regions. Conclusion: It can be concluded that low wall shear stress and opposition of direction of wall shear stress during a cardiac cycle may be increased risk of endothelial injury and formation of atherosclerosis plaque or calcified arterial wall segment. Therefore, these parameters can be used as index factors for diagnosing development of these diseases.