Hemodynamics factors and biomechanical forces play key roles in atherogenesis, plaque development and final rupture. In this paper, we investigated the flow field and stress field for different degrees of stenoses under physiological conditions. Disease is modelled as axisymmetric cosine shape stenoses with varying diameter reductions of 30%, 50% and 70%, respectively. A simulation model which incorporates fluid-structure interaction, a turbulence model and realistic boundary conditions has been developed. The results show that wall motion is constrained at the throat by 60% for the 30% stenosis and 85% for the 50% stenosis; while for the 70% stenosis, wall motion at the throat is negligible through the whole cycle. Peak velocity at the throat varies from 1.47 m/s in the 30% stenosis to 3.2m/s in the 70% stenosis against a value of 0.78 m/s in healthy arteries. Peak wall shear stress values greater than 100 Pa were found for > or 50% stenoses, which in vivo could lead to endothelial stripping. Maximum circumferential stress was found at the shoulders of plaques. The results from this investigation suggest that severe stenoses inhibit wall motion, resulting in higher blood velocities and higher peak wall shear stress, and localization of hoop stress. These factors may contribute to further development and rupture of plaques.
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机译：血液动力学因素和生物力学力在动脉粥样硬化，斑块形成和最终破裂中起关键作用。在本文中，我们研究了在生理条件下不同程度的狭窄的流场和应力场。疾病被建模为轴对称余弦形状的狭窄，其直径减小分别减小30％，50％和70％。已经建立了包含流体-结构相互作用，湍流模型和实际边界条件的仿真模型。结果表明，对于30％的狭窄，壁运动在喉部受60％的约束，对于50％的狭窄，壁运动受85％的约束;而对于70％的狭窄，在整个周期中，喉部的壁运动可以忽略不计。喉部的峰值速度从30％狭窄时的1.47 m / s变化到70％狭窄时的3.2m / s，而健康动脉的峰值速度为0.78 m / s。对于≥50％的狭窄，发现峰值壁切应力值大于100 Pa，这在体内可能导致内皮剥离。在斑块的肩部发现最大的圆周应力。这项研究的结果表明，严重的狭窄会抑制壁运动，从而导致更高的血流速度和更高的峰值壁切应力，以及环向应力的局部化。这些因素可能有助于进一步发展和斑块破裂。
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