Abstract: A vascular prosthesis (50) comprises a tube (52) of material other than autologous vascular tissue, the tube having an end formation for surgical connection direct to an opening formed in an artery, the formation comprising an enlarged chamber (54) having a heel (56) and a toe (58) at opposite ends of a first longer diameter parallel to the axis of the tube and a second shorter transverse diameter the enlarged chamber serving to promote localised movement of blood having a non-laminar nature with a shear stress inducing relationship to receiving arterial wall.