AN EXPERIMENTAL-STUDY TO EXAMINE THE PATENCY AND TISSUE-RESPONSE OF 2TYPES OF BIOSYNTHETIC GRAFT USED AS A REPLACEMENT FOR PORCINE INFERIOR VENA-CAVA

This experimental study has been carried out to evaluate biosynthetic grafts as vascular substitutes. Tubular segments of 35 X 8 mm made of (1) tanned ovine collagen and integral polyester mesh, either of the f irst (Omniflow I) or second generation (Omniflow II), or (2) polytetra fluoroethylene (e-PTFE), have been sutured in the infrarenal inferior vena cava of pigs, and removed 1 hour, 7, 14, 28, 56 and 112 days afte r implantation. The patency rate of biosynthetic grafts was higher tha n that of e-PTFE grafts (p<0.01). There was no significant difference between the patency of the first generation and second generation coll agen grafts. These results indicate that biosynthetic prostheses may b e suitable vascular substitutes in low flow and low pressure systems. Improvements in the collagen inner cover structure (Omniflow II vs. Om niflow I), producing greater mechanical endurance, did not enhance lon g-term patency or the healing patterns of biosynthetic grafts.