COMPARISON OF GIANTURCO Z-STENTS AND WALLSTENTS IN A HEMODIALYSIS ACCESS GRAFT ANIMAL-MODEL

PURPOSE: To compare the primary patency of two structurally different metallic stents in an animal model of hemodialysis access grafts. MATE RIALS AND METHODS: Nineteen synthetic femorofemoral arteriovenous shun ts were created in 10 dogs, After a 1-month period of maturation (duri ng which one graft thrombosed), stents were placed spanning the venous anastomosis. The grafts were divided into two treatment groups (Walls tent, n = 6, and Gianturco stent, n = 6) and a control group with no s tent (n = 6). Fistulograms and pressure measurements were obtained at monthly intervals for 6 months or until thrombosis of the graft. RESUL TS: Mean graft patency in the Wallstent group (112 days +/- 30) was si gnificantly shorter than in the control (157 days +/- 32, P < .03) or Gianturco (157 days +/- 32, P < .05) groups, Patency in the Gianturco stent group was no different from that in the control group, Stenosis due to intimal hyperplasia within the stents appeared greater in the W allstent group but did not achieve statistical significance, One Walls tent migration, three Gianturco stent shifts, and two Gianturco stent breakages occurred, Histologic examination revealed a necrotizing vasc ulitis in the portion of vein containing the stent in all grafts treat ed with the Gianturco stent but not in any other grafts. CONCLUSION: I n an animal model of hemodialysis access grafts, the Gianturco stent h ad longer primary patency than the Wallstent when placed across the ve nous anastomosis. However, stent fractures and focal necrotizing infla mmation may limit the use of the Gianturco stent in hemodialysis acces s.