Human dilated ascending aorta: Mechanical characterization via uniaxial tensile tests
Human dilated ascending aorta: Mechanical characterization via uniaxial tensile tests
复制标题
DOI：
10.1016/j.jmbbm.2015.08.021
复制
发表时间：
2016-01-01
影响因子：
3.9
通讯作者：
Auricchio, Ferdinando
中科院分区：
文献类型：
--
作者：
Ferrara, Anna;Morganti, Simone;Auricchio, Ferdinando
升主动脉瘤 (AsAA)，即主动脉第一部分的进行性局部扩张，是一种严重危及生命的疾病，通常没有任何症状。 AsAA 的形成与主动脉壁组织的变性有关，这会导致组织机械性能的变化，特别是导致壁应力增加和/或壁极限强度降低。如今，外科手术的决定通常基于 AsAA 直径，尽管这样的标准并不总是具有预测性。本研究的重点是 AsAA 组织的机械特性。标本是从 46 名患者通过心脏直视手术切除的扩张升主动脉部分切下的。根据单向应力-应变曲线测量峰值应变、峰值应力和最大弹性模量（即组织刚度）。这种（最终）机械特性是针对主动脉壁的不同区域（前部和后部）以及不同的样本方向（圆周和纵向）收集的。还研究了最终机械性能与患者年龄和性别的关系。获得的结果强调了 AsAA 组织的显着各向异性（在健康主动脉组织中也观察到），圆周方向的强度和刚度值高于纵向。在周向方向上，后部区域相对于前部区域也发现了更高的强度和刚度，而在纵向方向上发现了相反的结果。还强调了最终机械性能随老化而下降的趋势。最后，仅在圆周方向上观察到男性和女性之间的强度存在显着差异。 (C) 2015 Elsevier Ltd. 保留所有权利。
Aneurysms of the ascending aorta (AsAA), i.e., a progressive and localized dilatation of the first part of the aorta, represent a severe life-threatening condition, often occurring with no symptom. AsAA formation is associated with a degeneration of the aortic wall tissue, which leads to changes in the tissue mechanical properties, and in particular to increased wall stress and/or decreased wall ultimate strength. Nowadays, the decision to surgically operate is usually based on the AsAA diameter, although such a criterion is not always predictive.The present study focuses on the mechanical characterization of the AsAA tissues. Specimens were cut from portions of dilated ascending aorta excised from 46 patients through open-heart surgery. Peak strain, peak stress, and maximum elastic modulus (i.e., tissue stiffness) were measured from uniaidal stress-strain curved. Such (ultimate) mechanical properties were collected for different regions of the aortic wall (anterior and posterior) as well as for different specimen orientations (circumferential and longitudinal). Relationships of ultimate mechanical properties with patient age and sex were also investigated.The obtained results highlighted a significant anisotropy of the AsAA tissue (as also observed for healthy aortic tissues), with higher value of strength and stiffness in the circumferential than in the longitudinal direction. Higher strength and stiffness were also found in the posterior region with respect to the anterior one for the circumferential orientation, whereas an opposite result was found for the longitudinal orientation. A decreasing trend of ultimate mechanical properties with aging was also highlighted. Finally, a significant difference in the strength between male and female was observed only in the circumferential direction. (C) 2015 Elsevier Ltd. All rights reserved.