Konala Bhaskar Chandra, Das Ashish, Banerjee Rupak K
Department of Mechanical Engineering, University of Cincinnati, Cincinnati, OH 45221, USA.
Mol Cell Biomech. 2011 Mar;8(1):1-20.
Hemodynamic endpoints such as flow and pressure drop are often measured during angioplasty procedures to determine the functional severity of a coronary artery stenosis. There is a lack of knowledge regarding the influence of compliance of the arterial wall-stenosis on the pressure drop under hyperemic flows across coronary lesions. This study evaluates the influence in flow and pressure drop caused by variation in arterial-stenosis compliance for a wide range of stenosis severities. The flow and pressure drop were evaluated for three different severities of stenosis and tested for limiting scenarios of compliant models. The Mooney-Rivlin model defined the non-linear material properties of the arterial wall and the plaque regions. The non-Newtonian Carreau model was used to model the blood flow viscosity. The fluid (blood)-structure (arterial wall) interaction equations were solved numerically using the finite element method. Irrespective of the stenosis severity, the compliant models produced a lower pressure drop than the rigid artery due to compliance of the plaque region. A wide variation in the pressure drop was observed between different compliant models for significant (90% area occlusion) stenosis with 41.0, 32.1, and 29.8 mmHg for the rigid artery, compliant artery with calcified plaque, and compliant artery with smooth muscle cell proliferation, respectively. When compared with the rigid artery for significant stenosis the pressure drop decreased by 27.7% and 37.6% for the calcified plaque and for the smooth muscle cell proliferation case, respectively. These significant variations in pressure drop for the higher stenosis may lead to misinterpretation and misdiagnosis of the stenosis severity.
在血管成形术过程中，通常会测量诸如流量和压降等血流动力学终点，以确定冠状动脉狭窄的功能严重程度。目前尚缺乏关于动脉壁狭窄顺应性对充血性血流通过冠状动脉病变时压降影响的相关知识。本研究评估了在广泛的狭窄严重程度范围内，动脉狭窄顺应性变化对流量和压降的影响。针对三种不同严重程度的狭窄评估了流量和压降，并对顺应性模型的极限情况进行了测试。Mooney-Rivlin模型定义了动脉壁和斑块区域的非线性材料特性。采用非牛顿Carreau模型对血流粘度进行建模。使用有限元方法对流体（血液）-结构（动脉壁）相互作用方程进行了数值求解。无论狭窄严重程度如何，由于斑块区域的顺应性，顺应性模型产生的压降均低于刚性动脉。对于严重（90%面积闭塞）狭窄，不同顺应性模型之间观察到压降存在很大差异，刚性动脉、钙化斑块顺应性动脉和平滑肌细胞增殖顺应性动脉的压降分别为41.0、32.1和29.8 mmHg。与严重狭窄的刚性动脉相比，钙化斑块和平滑肌细胞增殖情况下的压降分别降低了27.7%和37.6%。对于较高程度的狭窄，这些压降的显著差异可能导致对狭窄严重程度的误解和误诊。
