title: Angiographic, hemodynamic and histological characterization of an arteriovenous fistula in rats.
abstract: BACKGROUND
  Our understanding of the pathogenesis of arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs) has been limited by the lack of adequate animal models. In this study we evaluate the time course of angiographic, hemodynamic and histopathological changes in an arteriovenous fistula in rats as a potential model.
  
  
  METHODS
  An arteriovenous fistula was created by a side-to-end anastomosis of the common carotid artery (CCA) to the external jugular vein (EJV). The animals underwent angiography of the fistula and were sacrificed 1, 7, 21, 42 or 90 days later. Flow and pressure measurements were performed in the CCA and ipsi- and contralateral EJV and detailed histological examination of whole mount sections of the fistula and cranium were done on fixed sections. Immunohistochemistry for CD31, smooth muscle alpha-actin and Ki-67 were performed.
  
  
  RESULTS
  Hemodynamic changes occur immediately after fistula formation creating a stable high flow, low resistant state. This induces a gradual increase in the inner diameter of the EJV and transverse sinus followed by a decrease in size of the transverse sinus. This decrease is associated with increased expression of alpha-actin in the wall of the sinus. The fistula becomes angiographically and histologically stable after 21 days.
  
  
  CONCLUSIONS
  This model describes the time course of hemodynamic and histopathological changes after occur after AVF formation. Stabilization after 21 days makes it an attractive model for mechanistic and therapeutic studies of AVFs.
authors.affiliation: Section of Neurosurgery, Department of Surgery and Pritzker School of Medicine, University of Chicago Medical Center, Chicago, Illinois 60637, USA.
authors.forename: R
authors.initials: R
authors.lastname: Yassari
authors.forename: T
authors.initials: T
authors.lastname: Sayama
authors.forename: B S
authors.initials: BS
authors.lastname: Jahromi
authors.forename: Y
authors.initials: Y
authors.lastname: Aihara
authors.forename: M
authors.initials: M
authors.lastname: Stoodley
authors.forename: R L
authors.initials: RL
authors.lastname: Macdonald
mesh_terms: D000818:Animals; D001166:Arteriovenous Shunt, Surgical; D001794:Blood Pressure; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology* / Q000601:surgery; D004195:Disease Models, Animal; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis* / Q000503:physiopathology*; D007601:Jugular Veins / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D011859:Radiography; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D013997:Time Factors