An endovascular prosthesis includes a tubular body and a mobile external coupling. The tubular body includes a graft material and stents coupled thereto, a forms a lumen therethrough. The mobile external coupling extends outwardly from the tubular body. The mobile external coupling includes a graft material and is generally frustoconically shaped. The mobile external coupling includes a base coupled to the tubular body, a top spaced from the tubular body, and a coupling lumen disposed between the base and the top, wherein the coupling lumen is in flow communication with the body lumen. The coupling graft material is a woven fabric with warp yarn which run generally parallel to a longitudinal axis of the mobile external coupling including a shape memory material.