Magnetically activated structures for minimally invasive endovascular therapy

项目摘要 磁激励结构（MAS）是一种柔性“智能”结构系统， 致动器或控制逻辑，其能够以受控的方式经受期望的变形。通过并入 磁偶极粒子在结构内处于预先指定的方向，MAS可以通过编程来 响应于外部环境刺激产生适应性和灵活的运动， 形状变形，从简单的弯曲和折叠，到一些复杂的变换。我们长久以来- 长期目标是利用MAS的多功能性，通过开发 主动可控的结构，与当前的治疗范式相反， 无源器件该项目的重点是腹主动脉瘤（AAA）。AAA异常 腹主动脉扩张，可能破裂，死亡率为75-80%。在大多数患者中， 解剖结构和合理的预期寿命，AAA的首选治疗方式是血管内治疗 动脉瘤修复术（EVAR）。腹主动脉瘤腔内修复术涉及经皮经股动脉进入动脉瘤部位， 在髂动脉内展开覆膜支架，以覆盖整个动脉瘤 从而有效地密封囊。腹主动脉瘤腔内修复术的主要缺点是发生内漏（血液渗漏）。 流入支架移植物周围的动脉瘤），如果由于支架引起，必须紧急治疗， 移植物移位、扭结或失效。在这里，MAS移植物将使用数值拓扑设计 优化模拟，使得结构可以通过非侵入性磁场原位变形 以便与血管壁相适应从而减轻渗漏或迁移。磁致动罐 也可用于方便复杂病例的分支治疗。观察到的任何MAS移植物移位 可以通过非侵入性地重新定位装置来校正。我们将 通过设计来自患者AAA的磁激活结构来实现这一目标 几何形状（具体目标1），并进行可行性研究，以评估制造和部署 以及计算流体动力学模拟，以比较MAS移植物与当前 用于治疗患者的移植物（具体目标2）。

PROJECT SUMMARY Magnetically activated structures (MAS) are flexible “smart” structural systems incorporating distributed actuators or control logics that can undergo desired deformations in a controlled manner. By incorporating magnetic dipole particles in pre-specified orientations within the structure, MAS can be programmed to generate adaptive and flexible movements in response to an external environmental stimulus through shape morphing, ranging from simple bending and folding, to some complex transformations. Our long- term goal is to leverage this versatility of MAS to optimize the treatment of vascular disease by developing actively controllable structures as opposed to the current treatment paradigm that involves static or passive devices. The focus of this project will be abdominal aortic aneurysms (AAA). AAA are abnormal dilations of the abdominal aorta that can rupture with a 75-80% fatality rate. In most patients with suitable anatomy and reasonable life expectancy, the preferred treatment modality for AAA is endovascular aneurysm repair (EVAR). EVAR involves percutaneous transfemoral access to the aneurysm site and endovascular deployment of stent grafts in the aortoiliac arteries in order to cover the entire aneurysm thereby effectively sealing the sac. The primary drawback of EVAR is the occurrence of endoleak (blood flows into the aneurysm around the stent graft), which must be treated urgently if it occurs due to stent- graft migration, kinking, or failure. Here, MAS-grafts will be designed using numerical topology optimization simulations such that the structures can be deformed in situ by a non-invasive magnetic field in order to conform to the vascular wall thereby mitigating leaks or migrations. Magnetic actuation can also be used to facilitate treatment of branches for complex cases. Any MAS-graft displacement observed during the follow-up period can be corrected for by non-invasively re-positioning the devices. We will accomplish this goal by the design of magnetically activated structures derived from patient AAA geometries (Specific Aim 1), and by conducting a feasibility study to assess fabrication and deployment of MAS grafts as well as computational fluid dynamics simulations to compare MAS grafts with the current grafts used to treat patients (Specific Aim 2).