A novel tissue engineering based endovascular aneurysm repair using electrospun scaffolds

Abdominal Aortic Aneurysms (AAA) consist of a dilation of the sub-renal aorta such that it is at least 150% of the original diameter. These aneurysms occur predominately in males at least 65 years of age and are generally asymptomatic. As the vessel dilates, there is an increased incidence of rupture. If rupture occurs, most individuals die before reaching the hospital. Therefore, it is critical to detect and treat these aneurysms before they rupture. Endovascular Aneurysm Repair (EVAR) is one of the two techniques used to treat an AAA and consists of inserting a graft through the femoral artery and positioning it over the dilation. The graft is deployed so that it barricades the aneurysmal sac from the blood flow while providing a viable conduit for blood flow.

While most current grafts consist of bioinert materials, the purpose of this study is to examine the feasibility of using a bioresorbable tissue engineering scaffold. A tissue engineering scaffold for aneurysm repair (TESAR) would promote cell attachment, infiltration and organization while acting as a typical EVAR graft. Hypothetically, a new aortic tissue wall could be formed and then the TESAR would bioresorb. The benefits of such a device may include better apposition to the native wall to reduce the incidence of endoleaks and the reduction of foreign materials implanted. A tissue engineering repair may also prove beneficial for diverse anatomical structures and allow appropriate remodeling.

The results of this study include a novel scaffold graft which may be a viable option for use in AAA repair based on the mechanical properties, in vitro cell response and in vivo implantation of the device. Studies determined appropriate manufacturing parameters for viable physical characteristics. In vitro studies using human aortic endothelial cells and human aortic smooth muscle cells in both static and dynamic culture environments demonstrated appropriate cell attachment and infiltration. The TESAR which was developed demonstrated promising results in a surgical swine AAA model in which an endothelium was present at 28 days and smooth muscle cells had infiltrated and began to organize within the TESAR material. In addition, the TESAR material was well adhered to the aorta wall and no thrombotic events were apparent.