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

项目摘要知识价值：腹主动脉瘤（AAAs）是指发生在病变血管薄弱部位的永久性、局部的主动脉肿胀。美国每年有14000人死于AAA破裂。近年来，由于机械应力被认为是动脉瘤破裂的原因，越来越多的文献关注于在特定患者的动脉瘤壁模型中定量评估应力分布和大小的方法。然而，血流在产生壁应力中的作用至今尚未得到解决。因此，该奖项的研究目标是开发一种结合实验和计算的生理壁应力分析（PWSA）程序，以评估准确复制单个患者AAAs的形状、非均匀厚度和机械性能的模型中的壁应力分布和最大值。为了达到这一目的，将从接受手术修复的患者身上收集AAA壁组织样本。将测量这些样品的机械性能，并使用复制病变壁刚度的弹性材料来制作复制患者病变形状的模型。该模型中的壁压将在模拟患者主动脉的流动条件下测量。然后，测量的壁压数据将被用作墙内应力水平的相应计算评估中的加载。更广泛的影响：建立一个使用患者特定信息准确评估AAA壁应力的方案，有可能对临床AAA管理产生重大影响。拟议的研究将首次使用具有真实几何形状和患者衍生力学特性的动脉瘤幻影对压力分布进行定量测量，并首次完全基于患者特性对壁面应力进行定量评估。此外，该项目将允许我们继续吸引本科生和研究生参与我们正在进行的研究工作，扩大研究培训，教育经验和为参与的学生提供的机会。此外，我们将充分利用塔夫茨大学现有的基础设施，在研究中招募和留住女性和代表性不足的少数族裔。这些项目包括计算机科学、生物医学工程和机器人技术的本科拓展项目。此外，塔夫茨大学医学院十多年来一直非常成功地开展由美国国立卫生研究院资助的少数族裔外展项目，允许代表性不足的本科生在塔夫茨大学度过暑假，参与生物医学科学研究。通过该项目产生的研究驱动型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重要的培训。

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.