Polymeric Endo-Aortic Paving (PEAP): Initial Development of a Novel Treatment for Abdominal Aortic Aneurysms

Abstract

Abdominal aortic aneurysm (AAA) is a prevalent disease in developed countries. While endovascular aneurysm repair is fairly successful, it has shortcomings. Polymeric endoluminal paving and sealing is a method that has previously been developed to treat a range of diseases. Our goal is to further develop this technique to treat AAA, a process we have named polymeric endo-aortic paving (PEAP). We hypothesize that PEAP will overcome many of the limitations associated with EVAR by providing a minimally invasive treatment which can be used on patients with complicated AAA geometries and reducing incidence of migration and endoleak. Additionally, we plan to incorporate drug delivery into PEAP to improve efficacy. The purpose of this work was to evaluate a potential graft material for PEAP and to develop a thrombus mimic which will aid in further PEAP development. Blends of polycaprolactone/polyurethane (PCL/PU) were assessed by characterizing their mechanical, thermoforming, and degradation properties. PCL/PU grafts have a similar stiffness to aortic tissue and can be thermoformed at temperatures approaching 37 degrees C. Blending PCL with PU significantly reduces PCL's degradation. An anisotropic hyperelastic strain energy function was developed for the PCL/PU blends and finite element modeling (FEM) was used to show that stress reduction on the AAA wall that can be achieved by PEAP is similar to current EVAR. Stiffness varies throughout the AAA thrombus, and thrombus mimics were developed that have similar stiffness, components, and structure to native AAA thrombus.