Truly impressive developments have taken place in recent years in the field of vascular surgery. A number of factors have been responsible for these striking advances, and among the most important has been the development of a satisfactory and effective arterial substitute. Although the use of arterial substitutes and the principles of blood vessel suture were demonstrated in experimental animals, and indeed in a few clinical cases, over a half century ago, for a number of reasons their wide clinical applicability has been a reality only a little over a decade. Indeed, the successful demonstration at that time that an arterial homograft could be used to replace a diseased arterial segment and could function effectively to provide normal arterial blood flow gave great impetus to further advancement in this field of surgery. It soon became apparent, however, that the arterial homograft was associated with a number of disadvantages, including particularly,