OBJECTIVES Ascending thoracic aortic aneurysms (aTAAs) carry a risk of acute type A dissection. Elective repair guidelines are based on diameter, but complications often occur below diameter threshold. Biomechanically, dissection can occur when wall stress exceeds wall strength. Aneurysm wall stresses may better capture dissection risk. Our aim was to investigate patient-specific aTAA wall stresses associated with a tricuspid aortic valve (TAV) by anatomic region. METHODS Patients with aneurysm diameter ≥4.0 cm underwent computed tomography angiography. Aneurysm geometries were reconstructed and loaded to systemic pressure while taking prestress into account. Finite element analyses were conducted to obtain wall stress distributions. The 99th percentile longitudinal and circumferential stresses were determined at systole. Wall stresses between regions were compared using one-way analysis of variance with post hoc Tukey HSD for pairwise comparisons. RESULTS Peak longitudinal wall stresses on aneurysms (n = 204) were 326 [standard deviation (SD): 61.7], 246 (SD: 63.4) and 195 (SD: 38.7) kPa in sinuses of Valsalva, sinotubular junction (STJ) and ascending aorta (AscAo), respectively, with significant differences between AscAo and both sinuses (P < 0.001) and STJ (P < 0.001). Peak circumferential wall stresses were 416 (SD: 85.1), 501 (SD: 119) and 340 (SD: 57.6) kPa for sinuses, STJ and AscAo, respectively, with significant differences between AscAo and both sinuses (P < 0.001) and STJ (P < 0.001). CONCLUSIONS Circumferential and longitudinal wall stresses were greater in the aortic root than AscAo on aneurysm patients with a TAV. Aneurysm wall stress magnitudes and distribution relative to respective regional wall strength could improve understanding of aortic regions at greater risk of dissection in a particular patient.

中文翻译：

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三尖瓣主动脉瓣相关升主动脉瘤的区域壁应力差异

目的 升主动脉瘤 (aTAAs) 具有发生急性 A 型夹层的风险。选择性修复指南基于直径，但并发症通常发生在直径阈值以下。在生物力学上，当壁应力超过壁强度时会发生夹层。动脉瘤壁应力可能更好地捕捉夹层风险。我们的目的是通过解剖区域研究与三尖瓣主动脉瓣 (TAV) 相关的患者特异性 aTAA 壁应力。方法对动脉瘤直径≥4.0 cm 的患者进行计算机断层扫描血管造影。在考虑预应力的情况下，重建动脉瘤几何形状并加载到全身压力。进行有限元分析以获得壁应力分布。在心脏收缩时确定第 99 个百分位的纵向和圆周应力。使用单向方差分析与事后 Tukey HSD 进行成对比较，比较区域之间的壁应力。结果 主动脉瘤 (n = 204) 的峰值纵向壁应力分别为 326 [标准偏差 (SD)：61.7]、246 (SD: 63.4) 和 195 (SD: 38.7) kPa，在 Valsalva 窦、窦管交界处 (STJ) 和上行窦中主动脉 (AscAo)，AscAo 与两个鼻窦 (P < 0.001) 和 STJ (P < 0.001) 之间存在显着差异。鼻窦、STJ 和 AscAo 的峰值周壁应力分别为 416 (SD: 85.1)、501 (SD: 119) 和 340 (SD: 57.6) kPa，AscAo 与两个鼻窦之间存在显着差异 (P < 0.001) 和STJ（P＜0.001）。结论 在有 TAV 的动脉瘤患者中，主动脉根部的周向和纵向壁应力大于 AscAo。