Sheep Model of Hemodialysis Arteriovenous Fistula Using Superficial Veins.

Current models of animal arteriovenous fistula (AVF) are swine models of femoral vein terminolaterally anastomosed to femoral artery, creating a deep AVF. This feature sets it aside from human AVFs using superficial veins. Our AVF model uses sheep superficial veins to create an AVF almost identical to human model. AVFs were created in six sheep using basilic veins sutured terminolaterally to brachial artery. Presurgery vein and artery diameters were measured. We measured AVFs and feeding arteries blood flows and diameters at 1, 3, and 5 weeks postsurgery. At 5 weeks we performed angiograms, euthanized animals, and harvested AVFs. Four animals completed the study. Three AVFs developed and were patent at 5 weeks; one thrombosed. Animal weight and presurgery vessels diameters predicted AVFs blood flows and diameters. Despite using vessels with diameters smaller than the ones recommended for human AVF, the Fistulas developed. Two animals died before the study conclusion for causes unrelated to surgery. This AVF model is anatomically almost identical to the human AVF and has a good maturation rate. It is a viable model for studying AVF maturation, devices intended to improve AVF maturation, AVF related procedures and can even support hemodialysis needles.