Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, United States.
J Biomech. 2012 Mar 15;45(5):790-8. doi: 10.1016/j.jbiomech.2011.11.019. Epub 2012 Jan 10.
Computational models have the potential to provide precise estimates of stresses and strains associated with sites of coronary plaque rupture. However, lack of adequate mathematical description of diseased human vessel wall mechanical properties is hindering computational accuracy. The goal of this study is to characterize the behavior of diseased human coronary and carotid arteries using planar biaxial testing. Diseased coronary specimens exhibit relatively high stiffness (50-210 kPa) and low extensibility (1-10%) at maximum equibiaxial stress (250 kPa) compared to human carotid specimens and values commonly reported for porcine coronary arteries. A thick neointimal layer observed histologically appears to be associated with heightened stiffness and the direction of anisotropy of the specimens. Fung, Choi-Vito and modified Mooney-Rivlin constitutive equations fit the multiaxial data from multiple stress protocols well, and parameters from representative coronary specimens were utilized in a finite element model with fluid-solid interactions. Computed locations of maximal stress and strain are substantially altered, and magnitudes of maximum principal stress (48-65 kPa) and strain (6.5-8%) in the vessel wall are lower than previously predicted using parameters from uniaxial tests. Taken together, the results demonstrate the importance of utilizing disease-matched multiaxial constitutive relationships within patient-specific computational models to accurately predict stress and strain within diseased coronary arteries.
计算模型有可能提供与冠状动脉斑块破裂部位相关的精确应力和应变估计。然而,缺乏对病变人体血管壁力学性能的充分数学描述,阻碍了计算的准确性。本研究的目的是使用平面双向测试来描述病变的人类冠状动脉和颈动脉的行为。与人类颈动脉标本和通常报道的猪冠状动脉值相比,病变的冠状动脉标本在最大等双轴应力(250kPa)下表现出相对较高的刚度(50-210kPa)和较低的延伸性(1-10%)。组织学观察到的厚新生内膜层似乎与刚度增加和标本各向异性的方向有关。Fung、Choi-Vito 和修正的 Mooney-Rivlin 本构方程很好地拟合了来自多个应力方案的多轴数据,并且代表性冠状动脉标本的参数被用于具有流固相互作用的有限元模型中。计算得到的最大应力和应变位置发生了很大变化,并且血管壁中的最大主应力(48-65kPa)和应变(6.5-8%)的幅度低于以前使用单轴试验参数预测的值。总之,这些结果表明,在基于患者的计算模型中使用与疾病匹配的多轴本构关系的重要性,以准确预测病变冠状动脉中的应力和应变。