Cilla Myriam, Monterde David, Peña Estefanía, Martínez Miguel Á
Applied Mechanics and Bioengineering, Aragón Institute of Engineering Research, University of Zaragoza, Zaragoza, Spain.
Proc Inst Mech Eng H. 2013 May;227(5):588-99. doi: 10.1177/0954411913479530. Epub 2013 Mar 6.
Rupture of atherosclerotic plaque, which is related to maximal stress conditions in the plaque among others, is a major cause of mortality. More careful examination of stress distributions in atherosclerotic plaques reports that it could be due to local stress behaviors at critical sites caused by cap thinning, inflammation, macroscopic heterogeneity, and recently, the presence of microcalcifications. However, the role of microcalcifications is not yet fully understood, and most finite element models of blood vessels with atheroma plaque ignore the heterogeneity of the plaque constituents at the microscale. The goal of this work is to investigate the effect of microcalcifications on the stress field of an atheroma plaque vessel section. This is achieved by performing a parametric finite element study, assuming a plane strain hypothesis, of a coronary artery section with eccentric atheroma plaque and one microcalcification incorporated. The geometrical parameters used to define and design the idealized coronary plaque anatomy and the microcalcification were the fibrous cap thickness and the microcalcification ratio, angle and eccentricity. We could conclude that microcalcifications should be considered in the modeling of this kind of problems since they cause a significant alteration of the vulnerable risk by increasing the maximum maximal principal stress up to 32%, although this increase of stress is not uniform (12% on average). The obtained results show that the fibrous cap thickness, the microcalcification ratio and the microcalcification eccentricity, in combination with the microcalcification angle, appear to be the key morphological parameters that play a determinant role in the maximal principal stress and accordingly in the rupture risk of the plaque.
动脉粥样硬化斑块破裂是导致死亡的主要原因之一，这与斑块中的最大应力状况等因素有关。对动脉粥样硬化斑块中应力分布的更仔细研究表明，这可能是由于帽变薄、炎症、宏观异质性以及最近发现的微钙化的存在导致关键部位的局部应力行为所致。然而，微钙化的作用尚未完全了解，并且大多数带有动脉粥样硬化斑块的血管有限元模型都忽略了斑块成分在微观尺度上的异质性。这项工作的目的是研究微钙化对动脉粥样硬化斑块血管段应力场的影响。这是通过进行参数化有限元研究来实现的，该研究假设平面应变假设，对包含偏心动脉粥样硬化斑块和一个微钙化的冠状动脉段进行研究。用于定义和设计理想化冠状动脉斑块解剖结构和微钙化的几何参数是纤维帽厚度、微钙化率、角度和偏心度。我们可以得出结论，在这类问题的建模中应考虑微钙化，因为它们会使最大主应力增加高达32%，从而显著改变易损风险，尽管这种应力增加并不均匀（平均增加12%）。所得结果表明，纤维帽厚度、微钙化率和微钙化偏心度，与微钙化角度相结合，似乎是在最大主应力中起决定性作用并因此在斑块破裂风险中起决定性作用的关键形态学参数。
