A Combined Experimental-Computational Method to Evaluate Abdominal Aortic Aneurysm Wall Stress

腹主动脉瘤（AAA）是一种永久性的、局部性的主动脉瘤，发生在病变血管变弱的地方。 AAA破裂每年在美国造成14，000人死亡。 由于机械应力被认为是破裂的原因，近年来，越来越多的文献涉及定量评价患者特定动脉瘤壁模型中应力分布和大小的方法。 然而，迄今为止，血流在产生壁应力中的作用尚未得到解决。 因此，该奖项的研究目标是开发一种结合实验-计算的生理壁应力分析（PWSA）程序，该程序可评估模型中的壁应力分布和最大值，该模型准确复制了个体患者AAA的形状、不均匀厚度和机械性能。 为了实现这一目标，将从接受手术修复的患者中采集AAA壁组织样本。 将测量这些样本的机械性能，并使用复制患病壁刚度的弹性材料来制作复制患者病变形状的模型。 将在模拟患者主动脉的流动条件下测量该模型中的壁压。 测得的壁压数据将被用作负荷在相应的计算评估的应力levelswithinthewall. broaderimpact：建立一个协议，准确评估AAA壁应力使用患者的具体信息有可能显着影响AAA的临床管理。 拟议的研究将提供第一个定量测量的压力分布，使用动脉瘤幻影与现实的几何形状和患者衍生的机械性能，以及第一个定量评价的壁应力完全基于患者的属性。 此外，该项目将使我们能够继续从事本科生以及研究生在我们正在进行的研究工作，扩大研究培训，教育经验和机会提供给参与的学生。 此外，我们将充分利用塔夫茨大学的基础设施，招募和留住女性和研究中代表性不足的少数民族。 其中包括计算机科学、生物医学工程和机器人技术的本科拓展课程。 此外，塔夫茨大学医学院进行了非常成功的NIH资助的少数民族外展计划超过十年，允许代表性不足的本科生在塔夫茨大学度过夏天，参与生物医学科学研究。 通过该项目产生的研究驱动的培训活动将使学生参与跨学科的计算思维，从而为未来的科学家和工程师提供关键培训。

PROJECT ABSTRACTIntellectual Merit:Abdominal aortic aneurysms (AAAs) represent permanent, localized swellings of the aorta that occur where the diseased vessel is weakened. AAA rupture accounts for 14,000 deaths in the US annually. A growing body of literature has developed in recent years concerned with methods for quantitatively evaluating the distribution and magnitude of stress in patient-specific models of the aneurysm wall, since mechanical stress is thought to be the cause of rupture. However, the role of blood flow in creating wall stress has not been addressed to date. Accordingly, the research objective of this award is to develop a combined experimental-computational physiologic wall stress analysis (PWSA) procedure that evaluates wall stress distributions and maxima in models accurately replicating the shape, non-uniform thickness and mechanical properties of individual patient AAAs. To accomplish this aim, AAA wall tissue samples will be collected from patients undergoing surgical repair. The mechanical properties of those samples will be measured, and an elastic material replicating the diseased wall stiffness will be used to fabricate a model replicating the shape of the patient lesion. Wall pressure in this model will be measured under flow conditions emulating the patient aorta. The measured wall pressure data will then be used as loading in a corresponding computational evaluation of stress levels within the wall.Broader Impact:Establishment of a protocol for accurate assessment of AAA wall stress using patient-specific information has the potential to significantly impact clinical AAA management. The proposed studies will provide the first quantitative measurements of pressure distributions using aneurysm phantoms with both realistic geometries and patient-derived mechanical properties, as well as the first quantitative evaluation of wall stress based entirely on patient properties. Furthermore, the project will permit us to continue to engage undergraduate as well as graduate students in our ongoing research efforts, expanding the research training, educational experience and opportunities available to the students involved. Moreover, we will take full advantage of infrastructure in place at Tufts University for recruiting and retaining women and underrepresented minorities in research. These include undergraduate outreach programs in Computer Science, Biomedical Engineering and robotics. In addition, the Tufts University School of Medicine has conducted a highly successful NIH-funded minority outreach program for over ten years, permitting underrepresented undergraduates to spend summers at Tufts involved in biomedical science research. Research-driven training activities generated through this project will engage students in cross-disciplinary computational thinking, thus providing critical training for future scientists and engineers.