The effects of anisotropy on the stress analyses of patient-specific abdominal aortic aneurysms
The effects of anisotropy on the stress analyses of patient-specific abdominal aortic aneurysms
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DOI：
10.1007/s10439-008-9490-3
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发表时间：
2008-06-01
影响因子：
3.8
通讯作者：
Vorp, David A.
中科院分区：
文献类型：
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作者：
Geest, Jonathan P. Vande;Schmidt, David E.;Vorp, David A.
肾下腹主动脉的局部扩张，称为腹主动脉瘤（AAA），通常是无症状的，最终可能导致破裂——这一事件与显著的死亡率相关。估计AAAs内的体内应力已被提出作为预测破裂可能性的有用工具。在目前的工作中，将先前导出的AAA壁各向异性关系应用于AAA患者特定的有限元模拟中。目前的工作中模拟了35个AAA，分为三组：选择性修复（n = 21），非破裂修复（n = 5）和破裂修复（n = 9）。采用各向异性和各向同性本构关系对峰值应力和应变进行了比较。当使用各向异性关系时，峰值应力显著增加（p < 0.001），即使在没有ILT的情况下（p = 0.014）。当使用各向同性和各向异性模拟时，与未破裂的AAAs相比，破裂的AAAs导致峰值应力升高，但这些比较没有达到显著性(p（ani) = 0.55, p(iso) = 0.73）。虽然各向同性或各向异性模拟都不能显著区分破裂与非破裂的AAAs，但使用各向异性模型时较低的p值表明，将其纳入患者特异性AAAs可能有助于更好地识别高风险AAAs。
The local dilation of the infrarenal abdominal aorta, termed an abdominal aortic aneurysm (AAA), is often times asymptomatic and may eventually result in rupture-an event associated with a significant mortality rate. The estimation of in-vivo stresses within AAAs has been proposed as a useful tool to predict the likelihood of rupture. For the current work, a previously-derived anisotropic relation for the AAA wall was implemented into patient-specific finite element simulations of AAA. There were 35 AAAs simulated in the current work which were broken up into three groups: elective repairs (n = 21), non-ruptured repairs (n = 5), and ruptured repairs (n = 9). Peak stresses and strains were compared using the anisotropic and isotropic constitutive relations. There were significant increases in peak stress when using the anisotropic relationship (p < 0.001), even in the absence of the ILT (p = 0.014). Rutpured AAAs resulted in elevated peak stresses as compared to non-ruptured AAAs when using both the isotropic and anisotropic simulations, however these comparisons did not reach significance (p(ani) = 0.55, p(iso) = 0.73). While neither the isotropic or anisotropic simulations were able to significantly discriminate ruptured vs. non-ruptured AAAs, the lower p-value when using the anisotropic model suggests including it into patient-specific AAAs may help better identify AAAs at high risk.