Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Czech Republic.
Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Czech Republic.
J Biomech. 2021 Dec 2;129:110861. doi: 10.1016/j.jbiomech.2021.110861. Epub 2021 Nov 9.
To obtain an experimental background for the description of mechanical properties of fibrous tissues of carotid atheroma, a cohort of 141 specimens harvested from 44 patients during endarterectomies, were tested. Uniaxial stress-strain curves and ultimate stress and strain at rupture were recorded. With this cohort, the impact of the direction of load, presence of calcifications, specimen location, patient's age and sex were investigated. A significant impact of sex was revealed for the stress-strain curves and ultimate strains. The response was significantly stiffer for females than for males but, in contrast to ultimate strain, the strength was not significantly different. The differences in strength between calcified and non-calcified atheromas have reached statistical significance in the female group. At most of the analysed stress levels, the loading direction was found significant for the male cohort which was also confirmed by large differences in ultimate strains. The representative uniaxial stress-strain curves (given by median values of strains at chosen stress levels) were fitted with an isotropic hyperelastic model for different groups specified by the investigated factors while the observed differences between circumferential and longitudinal direction were captured by an anisotropic hyperelastic model. The obtained results should be valid also for the tissue of the fibrous cap, the rupture of which is to be predicted in clinics using computational modelling because it may induce arterial thrombosis and consequently a brain stroke.
为了描述颈动脉粥样硬化纤维组织的力学性能，我们对 44 名颈动脉内膜切除术患者的 141 个标本进行了实验研究。记录了单轴拉伸应力-应变曲线以及破坏时的极限应力和应变。在这个队列中，我们研究了负荷方向、钙化存在、标本位置、患者年龄和性别对纤维组织的影响。研究结果表明，性别对纤维组织的应力-应变曲线和极限应变有显著影响。女性的响应明显比男性更硬，但与极限应变不同的是，强度没有显著差异。在女性组中，钙化和非钙化粥样硬化之间的强度差异达到了统计学意义。在大多数分析的应力水平下，加载方向对男性队列也有显著影响，这也通过极限应变的巨大差异得到了证实。根据所研究的因素，对不同组别的代表性单轴拉伸应力-应变曲线（由所选应力水平下应变的中位数给出）进行了各向同性超弹性模型拟合，而通过各向异性超弹性模型捕捉了圆周和纵向方向之间的差异。由于纤维帽的破裂可能导致动脉血栓形成，进而导致中风，因此在临床上需要使用计算模型来预测其破裂，我们认为所获得的结果也应该适用于纤维帽组织。
