a composite graft for a fluid - carrying vessel in a living body , comprising : an inner vessel comprising a biologic collagenic material that has been stabilized , an outer member surrounding at least a segment of the inner vessel and defining an annulus between the inner vessel and the sleeve , the outer member comprising a polymeric fabric , and a bioactive compound in said annulus , said bioactive compound being carried on a time - release vehicle . the bioactive compound is preferably an occlusion - preventing agent . alternatively , the sleeve includes the bioactive compound , either on its inner surface or integrally as part of its fibers .