Abstract: Embodiments of a uniformly porous membrane covering an endoprosthetic device, for example, a stent used to treat an aneurysm, are described. Some embodiments have a pore size and spacing that provides a material ratio of between 70-80% in the deployed state. Material ratio is the proportion of the total porous segment of the membrane that corresponds to membrane material, the remainder being pores. In some embodiments, pore size ranges from about 10-100 ?m. In some embodiments, pores are equidistantly spaced with pore spacing in a range of about 40-100 ?m. The combination of pore size and spacing are effective to provide a membrane that substantially prevents flow to the aneurysm, while maintaining flow to perforator vessels. In some embodiments the membrane includes permanently attached agents that promote attachment of endothelial cells or progenitors and healing of the aneurysm, or reduce immune responses detrimental to the healing process.

Abstract: A medical device (10) for insertion into a bodily vessel (6) to treat an aneurysm (5) having an aneurysm neck, the device (10) comprising: a mechanically expandable device (20) expandable from a first position to a second position, said mechanically expandable device (20) is expanded radially outwardly to the second position such that the exterior surface of said mechanically expandable device (20) engages with the inner surface of the vessel (6) so as to maintain a fluid pathway through said vessel (6); a therapeutically effective amount of a chemical compound comprising a biosynthesis accelerator to stimulate cell growth; and a polymer (30, 41, 42) mixed with the chemical compound to manage the release rate of the chemical compound; wherein the mechanically expandable device (20) provides a support for the release of the chemical compound within the aneurysm (5) to stimulate cell growth within the aneurysm (5) and close the aneurysm neck.