Electrospun Polyurethane Vascular Grafts for Cerebral Revascularization: A Pilot Study on Rats

Abstract

The current standard technique for vascular grafting in cerebral revascularization surgery employs the interposition of an autologous blood vessel. Technical complications have necessitated the development of a synthetic alternative, but classical biomaterials are not suited for small caliber vascular grafting due to the resulting neointimal hyperplasia and thrombosis. The electrospinning of polymers is a promising technique for the development of small vascular grafts. The in vivo performance and efficacy of electrospun polyurethane (ePU) grafts with an internal diameter of <1.5 mm have thus far not been evaluated. We developed a novel ePU graft, with a diameter of 1.25 mm, for implantation into the infrarenal aorta of rats. The patency rates of grafts after a 4-month period were equal to those reported in other studies using larger ePU graft diameters and equal or higher than in studies employing other biomaterials. We observed some loss in flow velocity throughout the grafts, which suggests a decreased elasticity of the graft compared to that of the native rat aorta. However, the grafts demonstrated good neo-endothelialization and minimal neointimal hyperplasia. Their porosity promoted cellular infiltration, as observed under tissue slide examination. Our results show that ePU vascular grafts with an internal diameter of <1.5 mm are promising candidates for vascular grafting in cerebral revascularization surgery.