Biosynthetic bacterial cellulose graft as arteriovenous fistula - a complement to existing synthetic grafts?

Abstract

Introduction: There is an increasing need for vascular prosthesis in dialysis medicine for the construction of arteriovenous (AV)-fistulas for dialysis access. The aims of this study were; a) to develop and validate a new experimental AV-fistula model for larger animals using grafts of bacterial cellulose (BC) between the common carotid artery and the external jugular vein; b) to observe the immediate and intermediate properties (macroscopic and angiographic patency and the macro- and micro thrombogenicity) of the grafts. Materials and Methods: As graftmaterial bacterial cellulose was used, produced around a preformed scaffold. Bacterial cellulose (BC) is a material produced by the bacteria acetobacter xylinum. A pilotstudy was conducted on 6 pigs to validate the animalmodel and the new graftmaterial. In the following survival study a BC-graft AV-fistula was constructed in 15 pigs. Results: In the pilot study, 5 out of 6 animals had a patent AV-fistula 4 hours after implantation. In the survival study, after 4 (n3) and 8 (n10) weeks an angiography was performed prior to explantation of the BC-graft. All grafts were occluded with a presumed platelet plug. We conducted an additional acute patch-test comparing the BC and expanded PolyTetraFluoro- Ethylene. A patch of BC and ePTFE was applied to the right and left common femoral artery respectively. At explantation three hours later, all BC-patches showed a thin gel like layer, most likely consisting of platelets, throughout the whole sur- face while the ePTFE-patch showed no, or minimal, signs of platelet adhesions. Conclusion: Theoretically the cellulose might be similar to autologous veins considering risk of infections and thrombo- genicity. The animal model and the graft material showed good potential in the pilot study. The survival study was discour- aging with the reason for occlusion still to be explained. Bacterial cellulose has a good potential but further development and studies need to be performed.