Department of Cardiology, Peking University First Hospital, Beijing, China.
Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China.
Sci Rep. 2017 Oct 24;7(1):13911. doi: 10.1038/s41598-017-14276-1.
Triaxial active and passive mechanical properties of coronary arteries are needed for understanding arterial mechanics in health and disease. The aim of the study was to quantify both active and passive strain energy functions in circumferential, axial and radial directions based on the experimental measurement. Moreover, a two-layer computational model was used to determine the transmural distribution of stresses and strains across the vessel wall. The first Piola-Kirchhoff stresses in the three normal directions had the approximate relationship as:[Formula: see text]. The two-layer model showed that circumferential Cauchy stresses increased significantly from the intima layer to the interface between media and adventitia layers (from ~80 to 160 kPa), dropped abruptly at the interface (from ~160 to <5 kPa), and increased slightly towards the outer boundary of the adventitia layer. In contrast, absolute values of radial Cauchy stress decreased continuously from the inner to outer boundaries of the vessel wall (from ~11 kPa to zero). Smooth muscle cell contraction significantly increased the ratio of radial to circumferential Cauchy stresses at the intima-media layer, which had the highest values at the intima layer.
为了理解健康和疾病状态下的动脉力学，需要对冠状动脉的三轴主动和被动力学特性进行研究。本研究的目的是基于实验测量，量化圆周向、轴向和径向的主动和被动应变能函数。此外，还使用了两层计算模型来确定血管壁的整个厚度方向上的应力和应变分布。三个法向方向上的第一 Piola-Kirchhoff 应力具有近似关系：[公式：见正文]。两层模型表明，圆周向的 Cauchy 应力从内膜层到中膜和外膜层之间的界面显著增加（从约 80kPa 增加到 160kPa），在界面处急剧下降（从约 160kPa 降低到<5kPa），并在外膜层的外边界处略有增加。相比之下，径向 Cauchy 应力的绝对值从血管壁的内边界到外边界连续减小（从约 11kPa 减小到零）。平滑肌细胞收缩显著增加了内膜-中膜层处的径向与圆周向 Cauchy 应力的比值，该比值在内膜层处达到最高值。
