Functional and structural response of arterialized femoral veins in a rodent AV fistula model.

Methods. AVFs were created by a handsewn end-to-side anastomosis between the femoral vein and the femoral artery in 15 rats. A group of sham-operated animals (n = 3) served as controls. Time-related functional and morphological AVF characteristics were assessed up to 12 weeks using ultrasound (15-MHz transducer) and were correlated to histopathological changes. Results. All rats survived surgery, and the patency rate was 93%. US showed a 2-fold increase in the fistula vein diameter and mean flow velocity as well as a 4-fold increase in the intima-media thickness without significant luminal loss. The afferent femoral artery exhibited no change in intima-media thickness and only minimal adaptive increases in diameter and flow velocity. Histological evaluation confirmed these observations. Conclusions. Our AVF model in the rat demonstrates maturation effects in fistula veins similar to typical clinical findings in haemodialysis patients. Noninvasive ultrasound proved to be a valuable tool for longitudinal in vivo monitoring of the fistulas in this rodent model.