Aragón Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain.
Biomech Model Mechanobiol. 2012 Sep;11(7):1001-13. doi: 10.1007/s10237-011-0369-0. Epub 2012 Jan 7.
Plaque rupture plays a role in the majority of acute coronary syndromes. Rupture has usually been associated with stress concentrations, which are mainly affected by the plaque geometry and the tissue properties. The aim of this study is to evaluate the influence of morphology on the risk of plaque rupture, including the main geometrical factors, and to assess the role of circumferential and axial residual stresses by means of a parametric 3D finite element model. For this purpose, a 3D parametric finite element model of the coronary artery with eccentric atheroma plaque was developed. Healthy (adventitia and media in areas without atheroma plaque) and diseased (fibrotic and lipidic) tissues were considered in the model. The geometrical parameters used to define and design the idealized coronary plaque anatomy were the lipid core length, the stenosis ratio, the fibrous cap thickness, and the lipid core ratio. Finally, residual stresses in longitudinal and circumferential directions were incorporated into the model to analyse the influence of the important mechanical factors in the vulnerability of the plaque. Viewing the results, we conclude that residual stresses should be considered in the modelling of this kind of problems since they cause a significant alteration of the vulnerable plaque region limits. The obtained results show that the fibrous cap thickness and the lipid core length, in combination with the lipid core width, appear to be the key morphological parameters that play a determinant role in the maximal principal stress (MPS). However, the stenosis ratio is found to not play a significant role in vulnerability related to the MPS. Plaque rupture should therefore be observed as a consequence, not only of the cap thickness, but as a combination of the stenosis ratio, the fibrous cap thickness and the lipid core dimensions.
斑块破裂在大多数急性冠状动脉综合征中起作用。破裂通常与应力集中有关，而应力集中主要受斑块几何形状和组织特性的影响。本研究旨在评估形态对斑块破裂风险的影响，包括主要的几何因素，并通过参数化 3D 有限元模型评估周向和轴向残余应力的作用。为此，开发了具有偏心动脉粥样硬化斑块的冠状动脉的 3D 参数有限元模型。模型中考虑了健康（无动脉粥样斑块的外膜和中膜）和患病（纤维化和脂质）组织。用于定义和设计理想化冠状动脉斑块解剖结构的几何参数是脂质核心长度、狭窄比、纤维帽厚度和脂质核心比。最后，将纵向和周向残余应力纳入模型中，以分析斑块脆弱性中的重要力学因素的影响。从结果可以看出，由于残余应力会显著改变易损斑块区域的边界，因此在建模这类问题时应考虑残余应力。研究结果表明，纤维帽厚度和脂质核心长度与脂质核心宽度结合起来，似乎是对最大主应力（MPS）起决定作用的关键形态参数。然而，狭窄比与 MPS 相关的易损性无关。因此，斑块破裂不仅应被视为帽厚度的结果，还应被视为狭窄比、纤维帽厚度和脂质核心尺寸的组合的结果。
