The surface roughness of the coronary artery is associated with the onset of atherosclerosis. The study applies, for the first time, the micro-scale variation of the artery surface to a 3D coronary model, investigating the impact on haemodynamic parameters which are indicators for atherosclerosis. The surface roughness of porcine coronary arteries have been detailed based on optical microscopy and implemented into a cylindrical section of coronary artery. Several approaches to rheology are compared to determine the benefits/limitations of both single and multiphase models for multi-scale geometry. Haemodynamic parameters averaged over the rough/smooth sections are similar; however, the rough surface experiences a much wider range, with maximum wall shear stress greater than 6 Pa compared to the approximately 3 Pa on the smooth segment. This suggests the smooth-walled assumption may neglect important near-wall haemodynamics. While rheological models lack sufficient definition to truly encompass the micro-scale effects occurring over the rough surface, single-phase models (Newtonian and non-Newtonian) provide numerically stable and comparable results to other coronary simulations. Multiphase models allow for phase interactions between plasma and red blood cells which is more suited to such multi-scale models. These models require additional physical laws to govern advection/aggregation of particulates in the near-wall region.

中文翻译：

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表面粗糙度和血液流变学对局部冠状动脉血流动力学的评估：多尺度计算流体动力学研究


冠状动脉的表面粗糙度与动脉粥样硬化的发生有关。该研究首次将动脉表面的微观变化应用于 3D 冠状动脉模型，研究其对作为动脉粥样硬化指标的血液动力学参数的影响。猪冠状动脉的表面粗糙度已基于光学显微镜进行了详细描述，并应用于冠状动脉的圆柱形切片。比较了几种流变学方法，以确定多尺度几何的单相和多相模型的优点/局限性。粗糙/光滑部分的平均血液动力学参数相似；然而，粗糙表面的范围要宽得多，最大壁面剪应力大于 6 Pa，而光滑段上的最大壁剪应力约为 3 Pa。这表明光滑壁假设可能忽略了重要的近壁血流动力学。虽然流变模型缺乏足够的定义来真正涵盖粗糙表面上发生的微观尺度效应，但单相模型（牛顿模型和非牛顿模型）提供了数值稳定且与其他冠状动脉模拟相当的结果。多相模型允许血浆和红细胞之间的相相互作用，这更适合这种多尺度模型。这些模型需要额外的物理定律来控制近壁区域颗粒的平流/聚集。