Magnetically activated structures for minimally invasive endovascular therapy

项目总结 磁力激活结构(MAS)是一种柔性的“智能”结构系统，融合了分布式结构 能够以受控方式经历所需变形的致动器或控制逻辑。通过将 在结构内预先指定取向的磁偶极粒子，MAS可以被编程为 通过以下方式响应外部环境刺激，进行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。我们的长- 学期目标是利用MAS的这种多功能性，通过开发 主动可控结构，而不是目前的治疗模式，涉及静态或 无源设备。该项目的重点将是腹主动脉瘤(AAA)。AAA异常 腹主动脉扩张可导致75%-80%的病死率。在大多数患者中，适当的 解剖和合理的预期寿命，AAA的首选治疗方式是血管内治疗 动脉瘤修复术(EVAR)EVAR涉及经皮经股动脉进入动脉瘤部位和 在主-髂动脉血管内放置支架以覆盖整个动脉瘤 从而有效地密封囊。EVAR的主要缺点是发生内渗漏(血液 流入支架移植物周围的动脉瘤)，如果由于支架- 移植物移位、扭结或失败。在这里，将使用数字拓扑来设计MAS-GRAFT 优化模拟，使得结构可以通过非侵入性磁场原位变形 以符合血管壁，从而减轻泄漏或迁移。磁致动器可以 也可用于方便复杂病例的分支治疗。观察到任何MAS移植物移位 在随访期内，可以通过非侵入性地重新定位设备来进行校正。我们会 通过设计来自患者AAA的磁性激活结构来实现这一目标 几何结构(具体目标1)，并进行可行性研究以评估制造和部署 以及计算流体力学模拟，以比较MAS移植物和当前 用于治疗患者的移植物(特定目标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).