A comparative study of complement activation by Denaflex, Bioflow, and BioPolyMeric vascular grafts

This study was performed to evaluate the degree of complement activation by three bovine arterial graft materials: Bioflow (Bio-Vascular Inc., a bovine artery fixed with dialdehyde starch), BioPolyMeric (St. Jude Medical Inc., a collagen conduit of bovine arterial origin, tanned with glutaraldehyde and covered with a Dacron mesh), and Denaflex (Baxter Edwards CVS Division, a bovine artery fixed with polyepoxy compounds). The grafts were rinsed by following the manufacturer's recommended procedures and thereafter incubated with normal human serum. CH50 assays were performed on the serum after incubation, and the percentage of complement activation for each sample was calculated relative to its control serum. The results indicated that the BioPolyMeric grafts activated the most complement, with about a 48% decrease in the CH50. The BioPolyMeric graft is composed of an outer polyester mesh and an inner collagenous tubing, exhibiting a nonreversible negative surface charge. After the polyester mesh was removed, the BioPolyMeric graft showed the highest complement activation in this study, suggesting that the glutaraldehyde fixed graft is more prone to complement activation than either the polyepoxy compound or dialdehyde starch fixed grafts. The complement fragment, C5a, generated during complement activation is strongly chemotactic for polymorphonuclear leukocytes and monocytes, which likely play early and long-lasting roles in regulating tissue reaction to the implanted graft.