Improving arteriovenous fistula maturation through anastomotic angle control: A preclinical goat study

Neointimal hyperplasia (NIH) is one of the primary constraints of hemodialysis vascular access, leading to arteriovenous fistula (AVF) maturation failure. One of these factors is the non-physiologic wall shear stress at the anastomosis. This pilot study tested a new external-assist device to standardize the anastomotic angle (~ 45°) and decrease undesirable hemodynamics. Six adult male goats underwent creation of an end-to-side arteriovenous fistula between the medial leg vein and the adjacent medial leg artery. The device group ( n = 3) received an assistive device to maintain an angle of approximately 45°, whereas the control group ( n = 3) underwent standard surgery. Patency was monitored clinically and via Doppler ultrasound for 28 days, followed by terminal explantation surgery for histopathological studies and serum MMP-9/TIMP-1 analysis. All device-equipped AVFs exhibited a strong thrill and maintained patency for 28 days. One control AVF thrombosed, and the other two developed severe venous outflow stenosis (VOS). Histology revealed markedly less NIH in the device group, with all device-group fistulas showing < 25% luminal narrowing compared with 25–100% in the control group. The TIMP-1/MMP-9 ratio, a marker of fibrosis (elevated in progression), was reduced in the device group compared to that in the control group. No foreign body reactions or infections were observed. These results suggest that the device is biocompatible and may improve early AVF patency by reducing NIH, warranting further preclinical evaluation.