A covered stent assembly comprising a tubular, expandable stent having a metallic framework covered with a cylinder of biocompatible, non-thrombogenic expandable material, such as heterologous tissue. In a preferred embodiment, the metallic framework is positioned coaxially within a cylinder of bovine pericardial tissue. A catheter may be used to deliver the stent assembly to a desired region in the lumen of a patient. The metallic framework is then expanded to seat the assembly within the lumen.