Since the report by Voorhees and associates in 1952 of the use of a weave of Vinyon-N as an artery substitute7 several materials have been used with good results. One of the common disadvantages is the lack of elasticity. To overcome this, Sanger and associates5,6 advocated knitting the grafts and have reported good results with knitted tubes of Orlon. The equivocal results obtained in this laboratory with knitted Orlon tubes replacing segments of the thoracic and abdominal aortas in 24 dogs have prompted this report.
Knitted Orion tubes * of three types were used. The abdominal aortic grafts were of two types. One was knitted with 48 stitches per inch of a 200 denier Orion (Fig. 1A) and had an air porosity † of 250. The other was knitted with 56 stitches per inch of a 200 denier Orlon and had an air porosity of 76 (Fig.