title: The Impact of Vein Mechanical Compliance on Arteriovenous Fistula Outcomes.
abstract: BACKGROUND
  Arteriovenous fistulae (AVFs) are the preferred access for hemodialysis but suffer a high early failure rate. The aim of this study was to determine how venous distensibility, as measured in vitro, relates to early outcomes of AVF formed with the sampled vein.
  
  
  METHODS
  Ethical approval was obtained for all aspects of this study. During AVF formation a circumferential segment of the target vein was sampled. Mechanical stress testing of the venous segments was undertaken using a dynamic mechanical analyzer, with progressive stress loading at 2 N/min to a maximum of 10 N or until sample disruption. Stress-strain curves were obtained for vein samples and Young's modulus (YM) calculated. Duplex assessment of the fistulae was undertaken at 30 days.
  
  
  RESULTS
  Thirty patients consented to participate with 29 samples obtained for analysis. Statistical comparison of YM demonstrated no relationship with common cardiovascular risk factors or dialysis status. Subject age greater than 65 was the only patient factor which showed a significant difference in YM (P = 0.05). Furthermore, a negative correlation was confirmed between age and YM (Pearson's r = -0.465, P < 0.05). Nine of the 29 subjects suffered an early AVF failure. Mann-Whitney U testing for differences in distribution reported that YM was significantly higher in those fistulas which failed (P < 0.005).
  
  
  CONCLUSIONS
  Reduced venous compliance appears to result in higher failure rates of AVFs. With the advancement of clinical tools such as speckle tracing ultrasound identification of vessel compliance in vivo may produce valuable additional information for clinicians planning AVF surgery.
authors.affiliation: Academic Vascular Surgical Unit, Hull & East Yorkshire NHS Trust/Hull York Medical School, Hull, UK.
authors.forename: George E
authors.initials: GE
authors.lastname: Smith
authors.affiliation: Academic Vascular Surgical Unit, Hull & East Yorkshire NHS Trust/Hull York Medical School, Hull, UK. Electronic address: Rachel.Barnes@hey.nhs.uk.
authors.forename: Rachel
authors.initials: R
authors.lastname: Barnes
authors.affiliation: Medical and Biological Engineering Department, School of Engineering, University of Hull, Hull, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Fagan
authors.affiliation: Academic Vascular Surgical Unit, Hull & East Yorkshire NHS Trust/Hull York Medical School, Hull, UK.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Chetter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects / Q000379:methods*; D003187:Compliance; D055119:Elastic Modulus; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D012307:Risk Factors; D013314:Stress, Mechanical; D013997:Time Factors; D017211:Treatment Failure; D018616:Ultrasonography, Doppler, Duplex; D034941:Upper Extremity / Q000098:blood supply*; D014680:Veins / Q000503:physiopathology / Q000601:surgery*