Mechanical stresses associated with flattening of human femoropopliteal artery specimens during planar biaxial testing and their effects on the calculated physiologic stress-stretch state
Mechanical stresses associated with flattening of human femoropopliteal artery specimens during planar biaxial testing and their effects on the calculated physiologic stress-stretch state
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DOI：
10.1007/s10237-019-01162-0
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发表时间：
2019-12-01
影响因子：
3.5
通讯作者：
Kamenskiy, Alexey
中科院分区：
文献类型：
--
作者：
Jadidi, Majid;Desyatova, Anastasia;Kamenskiy, Alexey
平面双轴测试通常用于表征动脉的机械性能，但在该测试过程中与样本展平相关的应力是未知的。我们量化了不同年龄的人股腘动脉（FPA）的扁平化效应，并确定了它们如何影响计算出的动脉生理应力-拉伸状态。使用平面双轴拉伸测试来自472个组织供体（年龄12-82岁，平均53 +/-16岁）的人FPA，并且使用形态测量和机械特征来评估变平效应。对基于不变量的模型的本构参数进行调整，以考虑标本变平，并用于计算7个年龄组FPA的生理应力、拉伸、轴向力、周向刚度和储存能量。双轴测试时，扁平样本的纵向刚度总体增加12 +/- 4%，周向刚度增加19 +/- 11%。在所有年龄组中，调整和未调整扁平化效应的应力-拉伸曲线之间的差异在纵向上相对恒定，但随着年龄的增长而增加。在所有年龄组中，这些差异小于受试者间变异性。生理应力、拉伸、轴向力、周向刚度和储存能量在有和没有扁平效应的情况下计算时在定性和定量上都相似。应力、拉伸、轴向力和储能随年龄增长而降低，但周向刚度在25至65岁之间保持相对恒定，表明稳态目标为0.75 +/- 0.02 MPa。与平面双轴测试相关的展平效应小于受试者间的变异性，并且对计算出的人体FPA的生理应力-拉伸状态几乎没有影响。
Planar biaxial testing is commonly used to characterize the mechanical properties of arteries, but stresses associated with specimen flattening during this test are unknown. We quantified flattening effects in human femoropopliteal arteries (FPAs) of different ages and determined how they affect the calculated arterial physiologic stress-stretch state. Human FPAs from 472 tissue donors (age 12-82 years, mean 53 +/- 16 years) were tested using planar biaxial extension, and morphometric and mechanical characteristics were used to assess the flattening effects. Constitutive parameters for the invariant-based model were adjusted to account for specimen flattening and used to calculate the physiologic stresses, stretches, axial force, circumferential stiffness, and stored energy for the FPAs in seven age groups. Flattened specimens were overall 12 +/- 4% stiffer longitudinally and 19 +/- 11% stiffer circumferentially when biaxially tested. Differences between the stress-stretch curves adjusted and non-adjusted for the effects of flattening were relatively constant across all age groups longitudinally, but increased with age circumferentially. In all age groups, these differences were smaller than the intersubject variability. Physiologic stresses, stretches, axial force, circumferential stiffness, and stored energy were all qualitatively and quantitatively similar when calculated with and without the flattening effects. Stresses, stretches, axial force, and stored energy reduced with age, but circumferential stiffness remained relatively constant between 25 and 65 years of age suggesting a homeostatic target of 0.75 +/- 0.02 MPa. Flattening effects associated with planar biaxial testing are smaller than the intersubject variability and have little influence on the calculated physiologic stress-stretch state of human FPAs.