Computational Tool to Assess Performance of the Aortic Trauma Stent-Grafts

 描述(申请人提供)：创伤是44岁以下人群的头号死因，所有创伤死亡的33%归因于胸腔内的主动脉损伤。使用支架移植物血管内重建术已经发展成为创伤患者的一线治疗方法，但这些支架移植物是为患有慢性退行性动脉疾病的老年患者设计的，对于年轻患者的较小和更成角度的胸主动脉并不理想。此外，患者活动性的增加和更具活力的年轻心血管系统施加的高循环负荷可能会导致支架-移植物材料失效，导致更高的发病率、死亡率和一生中昂贵的再干预。该项目的目标是创建一种计算工具，该工具可以确定创伤患者主动脉的最佳支架移植特性以及植入支架的长期力学行为。该工具将能够测量支架移植物植入年轻胸主动脉时的符合性，以及支架移植物的长期耐久性，这取决于其承受高周疲劳负荷的能力。我们建议通过三个具体的目标来实现这一点：在目标1中，我们将确定不同年轻创伤人群(20岁、20-29岁、30-45岁)的胸主动脉形态测量特征，这些特征对于使用从薄层CTA扫描获得的全面的3D动脉重建部署支架至关重要。在目标2中，我们将利用从每个年龄段的组织供体获得的胸主动脉壁的双向力学特性，并通过实验确定目前批准用于创伤的两种支架移植物(Gore C-Tag和Medtronic Valiant)的机械特性，建立在年轻创伤患者的主动脉中部署支架的电子模型。然后，我们将使用数学建模来使支架移植物承受典型的循环生理载荷，并评估由此产生的应力-应变场。在目标3中，我们将确定支架-移植物在模拟活体载荷下与主动脉内壁的适合性，以及通过使用应力分析和Goodman图评估设备承受高周疲劳载荷的能力来确定长期耐久性。将为每个创伤人群获取这些数据，以确定可能提高每个创伤组血管内治疗的急性和长期结果的设备的具体特征。这项拟议的研究将为年轻患者群体现有和尚未开发的血管内装置的电子比较有效性研究奠定基础，并将为创伤导向的血管内装置的分析设定新的标准，促进更好的支架移植物的开发。这项工作将促进申请者融入生物医学领域，增强她独立研究事业的潜力，同时为她未来寻求独立资金创造一个极好的利基市场。

 DESCRIPTION (provided by applicant): Trauma is the number one cause of death among people younger than 44 years of age, and 33% of all traumatic deaths are attributed to aortic injuries within the thorax. Endovascular reconstruction of traumatized aorta using stent-grafts has evolved as a first line therapy for trauma patients, but these stent-grafts were designed for elderly patients with chronic degenerative arterial diseases and are less than ideal for the smaller and more angulated thoracic aortas of young patients. In addition, the increased patient activity and high cyclic loads imposed by more dynamic younger cardiovascular systems may push stent-graft materials to failure resulting in higher morbidity, mortality and expensive reinterventions over the course of a lifetime. The goal of this project is to create a computationa tool that can determine the optimal stent-graft characteristics for the aorta of trauma patients and the mechanical behavior of the implanted stent-grafts over the long-term. This tool will be able to measure the conformability of the stent-graft when implanted in the young thoracic aorta and the long-term durability of the stent-graft as determined by its capability to withstand high-cycle fatigue loads. We propose to accomplish this by three Specific Aims: In Aim 1 we will determine the morphometric features of the thoracic aorta in different young trauma populations (<20, 20-29, 30-45 years old) that are critical for stent-graft deployment using comprehensive 3D arterial reconstructions derived from thin-section CTA scans. In Aim 2 we will build in silico models of stent-grafts deployed in the aortas of young trauma patients using biaxial mechanical properties of thoracic aortic wall obtained from tissue donors of each age group, and experimentally determined mechanical properties of two stent-grafts (GORE C-Tag and Medtronic Valiant) that are currently approved for trauma. We will then use mathematical modeling to subject the stent-grafts to typical cyclic physiologic loads and assess the resulting stress-strain fields. In Aim 3 we will determine stent-graft conformability to the inner aortic wal when subjected to simulated in vivo loads, and long-term durability as determined by the capability of the device to withstand high-cycle fatigue loads assessed by using stress analysis and Goodman diagrams. These data will be acquired for each trauma population to identify specific characteristics of the devices that may enhance the acute and long-term outcomes of endovascular treatments in each trauma group. The proposed study will lay the foundation for in silico comparative effectiveness studies for existing and yet-to-be developed endovascular devices for young patient populations and will set new standards for analysis of trauma-oriented endovascular devices, facilitating the development of better stent-grafts. This work will promote integration of the applicant into the biomedical field and enhance her potential for independent research career while carving out an excellent niche for her to pursue independent funding in the future.