Patency and durability of small diameter silicone rubber vascular prostheses

This study evaluated the long-term patency and durability of 6 mm internal diameter (ID), 18-30 micron pore size replamineform silicone rubber vascular prostheses as canine aortic interposition and arteriovenous (A-V) grafts. Six prostheses (6 mm ID x 8 cm length) were evaluated as aortic grafts for 24 to 30 months, and 10 prostheses (6 mm ID x 8-10 cm length) were studied as A-V grafts from 2 weeks to 10 months. Three of the A-V prostheses were punctured for sham dialysis once or twice/week with two 16 gauge needles (total of approximately 50 needle punctures). The porous wall of the silicone rubber prostheses was incorporated with capillaries and fibrohistiocytic cellular elements from 2 weeks of implantation. This cellular incorporation remained constant up to 2 1/2 years. Needle puncture of the arteriovenous grafts over a 3 to 5 month period produced no complications such as thrombosis, perigraft hematoma formation or bleeding through the puncture site. The silicone rubber sealed the holes with no evidence of tearing. Explanted prostheses had no evidence of enlargement or false aneurysm formation. This study supports our hypothesis that Replamineform silicone rubber prostheses are hemocompatable and demonstrate long-term durability for dialysis access. Clinical evaluation of this graft is planned in the near future.