Heterograft biocompatibility without proteolytic digestion

Abstract

Bovine and sheep carotid heterografts (BED and S-ED) were modified by sequential treatment with 95% ethanol and 1.3% dialdehyde starch and stored in 70% ethanol. Compared with ficin digested, dialdehyde tanned bovine carotid artery (B-FD), chemical treatment produced heterografts with greater in vitro anastomotic tensile strength and significantly reduced surface clotting time. Seven of 20 canine inferior caval implants of B-ED heterografts remained patent for periods up to 4 weeks while 4 of 5 B-FD interpositions thrombosed within 2 hr. A patency rate of over 90% was obtained in canine abdominal and thoracic aorta B-ED and S-ED interpositions during a follow up period of 3 to 6 months. As arteriovenous fistulas B-ED heterografts maintained excellent patency, tolerated repetitive percutaneous puncture and exhibited self sealing capability. Microscopic examination of longterm B-ED implants showed smooth intimal surfaces with no fibrin deposition or morphologic evidence of rejection. In contrast to the ficin digested heterograft, ethanol-dialdehyde processing suppresses antigenic potential but preserves structural integrity. The end product retains components of the heterograft wall and results in a nonviable, biocompatible conduit with improved thromboresistance and greater strength.