Abstract: The invention relates to a vascular endoprosthesis including a device for preventing any endoleak after an angioplasty. The invention more particularly but not restrictively relates to a vascular endoprosthesis for a patient suffering from an abdominal aortic aneurysm.

Abstract: The present invention provides vascular prostheses free of any substance that counteracts an anticoagulant comprising a base material, the base material having inner and outer surfaces, wherein the outer surface has a layer of a material capable of reducing the porosity of said prosthesis to blood or body fluid and a coating of compounded heparin bound thereon, and the inner surface has a coating of compounded heparin bound thereon, the compounded heparin comprising heparin and a cationic surfactant. The present invention also provides a method for forming a vascular prosthesis. The vascular prostheses of the present invention exhibit low porosity at the time of implantation of the prosthesis thereby obviating the need for pre-clotting the prosthesis to avoid leakage or hemorrhaging of blood through the prosthesis.