Improvement of methods for accurate diagnosis and localization of peripheral arterial lesions has proceeded concurrently with the recent development of surgical techniques for replacement or by-pass of these lesions. Thus there is increasing need for arterial replacement and for determination of the best material for these replacements. While banks of homologous arteries are available in many centers, it appears unlikely that such supplies will for long be able to meet the increasing demands for small-vessel replacement because of difficulties in obtaining, storing, and preserving such homologous vessels. The practical use of heterologous vessels still lies in the future. Synthetic tubes offer advantages in terms of ready availability and easy storage and at present appear to function satisfactorily as replacements for large vessels, such as the aorta. Unfortunately, others as well as ourselves find that presently available small-caliber synthetic tubes often become thrombosed when used for peripheral arterial replacement. Autogenous vein