Magnetically activated structures for minimally invasive endovascular therapy

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).