A new type of endovascular prosthesis was inserted in 28 animals and evaluated for several factors, including thrombogenicity, tendency to migrate, critical implant zones, and incorporation into the vascular wall. The new prosthesis is a woven, multifilament structure of stainless steel alloy; its inherent elastic, self-expanding characteristics hold it against the vessel walls. Forty-seven endoprostheses (3-5 mm in diameter, 15-50 mm long) were percutaneously implanted with either a 6-F introducer sheath, a coaxial 9-F catheter, or a 0.014-inch (0.036-cm) guide wire into the femoropopliteal, coronary, carotid, and renal arteries and iliac veins. Anticoagulant or platelet antiaggregating agents were not used before or after implantation. Angiographic and histologic analyses showed that the prosthesis had a very low thrombogenicity when it was well adapted to the native vessel diameter and that it was incorporated into the vessel wall by a new intima by the 3d week after implantation. No migration occurred, and branch vessel flow was preserved even in those vessels in which ostia were traversed by the prosthesis. This prosthesis has potential for clinical application in the treatment of postangioplasty restenoses, particularly in the coronary arteries.