title: Functional and structural response of arterialized femoral veins in a rodent AV fistula model.
abstract: BACKGROUND
  Neointimal hyperplasia is considered to be the major cause of arteriovenous fistula (AVF) failure, resulting in vein wall thickening, stenosis and, ultimately, occlusion. Ultrasound (US) has been shown to be effective for detecting these morphological changes in patients. The aim of this study was to develop an experimental AVF model in the rat that shows typical features of fistula maturation and allows longitudinal monitoring of fistula veins by high-resolution ultrasound.
  
  
  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.
authors.affiliation: Department of Vascular Surgery, University Hospital RWTH Aachen, Germany. slanger@ukaachen.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Langer
authors.forename: Christian
authors.initials: C
authors.lastname: Heiss
authors.forename: Niklas
authors.initials: N
authors.lastname: Paulus
authors.forename: Nuran
authors.initials: N
authors.lastname: Bektas
authors.forename: Gottfried
authors.initials: G
authors.lastname: Mommertz
authors.forename: Zuzanna
authors.initials: Z
authors.lastname: Rowinska
authors.forename: Ralf
authors.initials: R
authors.lastname: Westenfeld
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Jacobs
authors.forename: Michael
authors.initials: M
authors.lastname: Fries
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Koeppel
mesh_terms: D000818:Animals; D001166:Arteriovenous Shunt, Surgical / Q000379:methods; D005260:Female; D005268:Femoral Vein / Q000000981:diagnostic imaging* / Q000601:surgery*; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D014463:Ultrasonography