Aryan Hiwa, Rasi Melika, Asiaei Sasan
School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran.
Clinical Research Development Center of Imam Khomeini, Mohammad Kermanshahi, and Farabi Hospitals, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Comput Methods Biomech Biomed Engin. 2025 Jul 15:1-28. doi: 10.1080/10255842.2025.2530654.
Atherosclerosis, a primary cause of cardiovascular diseases, arises from intricate interactions between hemodynamic factors and vascular biology. This condition is characterized by a reduction in luminal cross-sectional area, which consequently impairs blood supply. In this study, patient-specific models of a stenosis carotid artery and its digitally-created healthy counterpart were reconstructed from CT scans. Employing the finite element method and a two-way fluid-structure interaction (FSI) coupling approach, non-Newtonian simulations of pulsatile and laminar blood flow were performed. The arterial wall was modeled as a linear, elastic, isotropic, and homogeneous material. The presence of plaque led to an approximately two-fold increase in peak velocity within the stenotic region, rising from approximately 0.3 m/s in the healthy model to 0.7 m/s, directly attributable to the reduced luminal area. The maximum shear stress of the wall at the location of the plaque reached 40 Pa. Furthermore, the maximum wall displacement increased from 1.5 mm in the healthy artery to 1.7 mm in the stenosis artery. While pressure results indicated minor localized increases and decreases before and after the plaque site, respectively, these changes did not significantly affect the total arterial pressure. Examination of blood flow streamlines revealed flow recirculation regions in the carotid sinus bulb of both arteries. In the stenosis artery, an additional and more pronounced flow recirculation region formed distal to the plaque, owing to the post-stenotic expansion. This phenomenon led to a substantial increase of approximately 240% in the oscillatory shear index (OSI) within the internal carotid artery branch. The relative residence time (RRT) remained relatively constant in the common carotid artery and the bifurcation region. However, RRT decreased by approximately 40% in the carotid branches, predominantly in the external carotid artery. Comparison of hemodynamic parameters and biological indices between healthy and stenosed arteries suggests that atherosclerotic plaques significantly alter local hemodynamics, potentially creating novel regions susceptible to atherosclerosis that are absent in healthy artery. In the healthy artery, about 8.3% of the vessel area was at risk for disease (TAWSS < 0.4 Pa), but this increased to 20% in the stenosed artery due to plaque accumulation, a 2.4-fold expansion. Regarding RRT, an increase was observed; areas with RRT > 10 expanded by approximately 1.6 times in the stenosed artery (from 3.1% in healthy to 5% in diseased).
动脉粥样硬化是心血管疾病的主要病因，由血流动力学因素与血管生物学之间复杂的相互作用引发。这种病症的特征是管腔横截面积减小，从而损害血液供应。在本研究中，从CT扫描重建了特定患者的狭窄颈动脉模型及其数字化创建的健康对应模型。采用有限元方法和双向流固耦合（FSI）方法，对脉动和层流血液流动进行了非牛顿模拟。动脉壁被建模为线性、弹性、各向同性和均匀的材料。斑块的存在导致狭窄区域内的峰值速度增加了约两倍，从健康模型中的约0.3m/s升至0.7m/s，这直接归因于管腔面积减小。斑块位置处壁面的最大剪应力达到40Pa。此外，最大壁面位移从健康动脉中的1.5mm增加到狭窄动脉中的1.7mm。虽然压力结果表明在斑块部位之前和之后分别有轻微的局部升高和降低，但这些变化并未显著影响总动脉压力。对血流流线的检查揭示了两条动脉的颈动脉窦球部存在血流再循环区域。在狭窄动脉中，由于狭窄后扩张，在斑块远端形成了一个额外的且更明显的血流再循环区域。这种现象导致颈内动脉分支内的振荡剪切指数（OSI）大幅增加约240%。相对停留时间（RRT）在颈总动脉和分叉区域保持相对恒定。然而，RRT在颈动脉分支中下降了约40%，主要在外颈动脉中。健康动脉和狭窄动脉之间血流动力学参数和生物学指标的比较表明，动脉粥样硬化斑块显著改变局部血流动力学，可能产生健康动脉中不存在的易患动脉粥样硬化的新区域。在健康动脉中，约8.3%的血管面积有患病风险（壁面切应力<0.4Pa），但由于斑块堆积，在狭窄动脉中这一比例增加到20%，扩大了2.4倍。关于RRT，观察到有所增加；RRT>10的区域在狭窄动脉中扩大了约1.6倍（从健康时的3.1%增加到患病时的5%）。
