Characterizing polymers for cardiovascular devices

Abdominal aortic aneurysm (AAA) occurs in developed nations. The current treatment, endovascular aneurysm repair (EVAR), while successful, has shortcomings. A solution to the concerns with EVAR is a polymeric endo-aortic paving (PEAP). Our goal is to further develop this treatment for AAA. We hypothesize that PEAP will overcome the current limitations associated with current AAA repair, while maintaining the desirable qualities of these materials are biocompatibility, thermoformability, and material compliance with aortic tissue. The purpose of this work was to evaluate potential PEAP material candidates, which include acrylate-based shape memory polymers (SMPs), polycaprolactone (PCL) and polyurethane (PU) blends, and finally a PCL-based bioresorbable copolymer poly (ester-urethane-urea) (PEUU). Materials were assessed by characterization of their chemical, thermomechanical and degradation properties. It was determined that acrylate- SMPs were too stiff to be candidates for use in PEAP. The control of the PEUU copolymer composition yielded a material that had increased degradability while maintaining valuable characteristics of the PCL/PU blend prior to, during, and following degradation. The difference between the PU hydrophobicity dictated MTM sensitivity to water immersion and degradation characteristics. Conventional statistics were used to develop three models for predicting key properties of PEUU. Important variables, such as PCL Mn, temperature, and crystallinity were found to impact both copolymer microstructure and mechanical properties