title: Arteriovenous fistulas for hemodialysis: application of high-frequency US to assess vein wall morphology for cannulation readiness.
abstract: OBJECTIVE
  To determine whether venous wall thickness and hoop (circumferential) stress, as determined with high-frequency ultrasonography (US), can predict cannulation readiness in arteriovenous fistulas (AVFs).
  
  
  METHODS
  Institutional review board approval and informed consent were obtained for this prospective study. To determine the US appearance of the venous wall, an AVF specimen was excised and scanned in a bath of degassed lactated Ringer solution with a 55-MHz probe. The appearance of the wall at high-frequency US was correlated with histologic findings. High-frequency (40-55-MHz) US was used to image the near-field AVF venous wall of 14 men (mean age, 59 years ± 11 [standard deviation]) and six women (mean age, 55 years ± 14) with newly created AVFs within 1 week of cannulation between January 2008 and December 2009. Measurements of the intima-media thickness (IMT) were generated by three independent observers who were blinded to outcomes. Intraclass correlation analysis was performed. Cannulation readiness was defined as no extravasation during the first dialysis treatment.
  
  
  RESULTS
  By using high-frequency US, the IMT was defined as the sum of a thin echogenic blood-intima interface and a uniform hypoechoic media. The mean IMT of the no extravasation group (0.16 mm ± 0.03) was greater than that of the extravasation group (0.10 mm ± 0.02) (P < .001). A minimum threshold IMT of 0.13 mm (P < .001) was associated with successful cannulation. The mean hoop stress of the no extravasation group (246 kPa ± 57) was lower than that of the extravasation group (530 kPa ± 199) (P < .001). A maximum hoop stress threshold of 248 kPa was associated with successful cannulation (P = .009).
  
  
  CONCLUSIONS
  Venous IMT and hoop stress assessed with high-frequency US can predict cannulation readiness in AVFs that are clinically deemed mature.
authors: Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors: Arash
authors: A
authors: Jaberi
authors: Derek
authors: D
authors: Muradali
authors: Rosa M
authors: RM
authors: Marticorena
authors: Niki
authors: N
authors: Dacouris
authors: Adrien
authors: A
authors: Boutin
authors: Anna M
authors: AM
authors: Mulligan
authors: Peter D
authors: PD
authors: Ballyk
authors: Vikramaditya
authors: V
authors: Prabhudesai
authors: Vern M
authors: VM
authors: Campbell
authors: Sandra M
authors: SM
authors: Donnelly
mesh_terms: D001166:Arteriovenous Shunt, Surgical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis; D017539:Tunica Intima / Q000000981:diagnostic imaging*; D017540:Tunica Media / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods*