The degeneration of the arterial wall at the basis of the ascending thoracic aortic aneurysm (ATAA) is a complex multifactorial process, which may lead to clinical complications and, ultimately, death. Individual genetic, biological or hemodynamic factors are inadequate to explain the heterogeneity of ATAA development/progression mechanisms, thus stimulating the analysis of their complex interplay.

Here the disruption of the hemodynamic environment in the ATAA is investigated integrating patient-specific computational hemodynamics, CT-based in vivo estimation of local aortic stiffness and advanced fluid mechanics methods of analysis. The final aims are (1) deciphering the ATAA spatiotemporal hemodynamic complexity and its link to near-wall topological features, and (2) identifying the existing links between arterial wall degeneration and hemodynamic insult. Technically, two methodologies are applied to computational hemodynamics data, the wall shear stress (WSS) topological skeleton analysis, and the Complex Networks theory. The same analysis was extended to the healthy aorta.

As main findings of the study, we report that: (1) different spatiotemporal heterogeneity characterizes the ATAA and healthy hemodynamics, that markedly reflect on their WSS topological skeleton features; (2) a link (stronger than canonical WSS-based descriptors) emerges between the variation of contraction/expansion action exerted by WSS on the endothelium along the cardiac cycle, and ATAA wall stiffness. The findings of the study suggest the use of advanced methods for a deeper understanding of the hemodynamics disruption in ATAA, and candidate WSS topological skeleton features as promising indicators of local wall degeneration.

升胸主动脉瘤 (ATAA) 基础的动脉壁退化是一个复杂的多因素过程，可能导致临床并发症并最终导致死亡。个体遗传、生物或血液动力学因素不足以解释 ATAA 发展/进展机制的异质性，从而刺激对它们复杂相互作用的分析。

在这里，结合患者特定的计算血流动力学、基于 CT的局部主动脉僵硬度的体内估计和先进的流体力学分析方法，研究了 ATAA 中血流动力学环境的破坏。最终目标是 (1) 破译 ATAA 时空血流动力学复杂性及其与近壁拓扑特征的联系，以及 (2) 确定动脉壁变性和血流动力学损伤之间的现有联系。从技术上讲，有两种方法应用于计算血流动力学数据、壁面剪应力 (WSS) 拓扑骨架分析和复杂网络理论。相同的分析扩展到健康的主动脉。

作为研究的主要发现，我们报告说：（1）不同的时空异质性表征了 ATAA 和健康的血流动力学，这显着反映了它们的 WSS 拓扑骨架特征；(2) 在 WSS 沿心动周期对内皮施加的收缩/扩张作用的变化与 ATAA 壁刚度之间出现了联系（比基于 WSS 的规范描述符更强）。该研究的结果表明，可以使用先进的方法更深入地了解 ATAA 中的血流动力学破坏，并将候选 WSS 拓扑骨架特征作为局部壁退化的有希望的指标。