A new type of endovascular prosthesis has been developed using a unique metal alloy (nitinol) with a heat-sensitive memory. Nitinol wire coil grafts were straightened in ice water and passed into the canine aorta via catheter, where they reformed into their original shapes. Follow-up aortograms demonstrated long-term patency with minimal thrombus formation. Nitinol endovascular coil grafts may eventually be used in the nonsurgical treatment of several forms of vascular disease.