The geometry of arteriovenous fistulas using endothelial nitric oxide synthase mouse models

Background: Arteriovenous fistula (AVF) maturation failure is a significant clinical problem in the hemodialysis population. Geometric parameters of human AVFs were associated with AVF development, but causative studies are lacking. We characterized mouse AVF geometry using endothelial nitric oxide synthase (NOS3) mouse models. Methods: Carotid jugular AVFs were created in NOS3 overexpression (OE), knockout (KO), and wild type (WT) mice. At 7 and 21 days post-creation, black blood MR images of AVFs were acquired and used to build 3D reconstructions of AVF lumens. We used these reconstructions to calculate the lumen area, lumen centerline, and centerline-derived parameters: anastomosis angle, tortuosity, nonplanarity angle, and location of maximal distance between the feeding artery and AVF vein. Inter- and intra-user variabilities were also determined. Results: When all mice were considered, increased minimum AVF venous lumen area was accompanied by increased venous tortuosity and increased distance between the artery and vein, with both remaining in-plane with the anastomosis. At day 7, the lumen area of AVFs from all strains was 1.5-2.5 fold larger than native veins. Furthermore, at day 21, AVF lumen in NOS3 OE (4.04±1.43 mm2) was significantly larger than KO (2.74±1.34 mm2) and WT (2.94±1.30 mm2) mice (p