title: Prediction of failure of native arteriovenous fistulas using 'on-line' fistula flow measurements.
abstract: BACKGROUND
  Measurement of blood flow within native arteriovenous fistula during haemodialysis is recommended to detect incipient fistula failure. In the present study the value of such flow measurements was assessed in a group of patients on maintenance haemodialysis, with access via native arteriovenous fistulas.
  
  
  METHODS
  Flow was measured using the 'on-line' thermodilution technique, on three separate occasions, and correlated with subsequent fistula failure within 6 months.
  
  
  RESULTS
  Of the 53 patients studied, there were six failures (three thromboses and three inadequate dialysis filtration rates). Flow rates in patients who progressed to fistula failure were significantly less than flow rates in patients whose fistulas did not fail (U = 13.0, P < 0.0003). Failure was no more common in one type of fistula than another (type fistula: F = 0.29, P = 0.88; flow predicting failure: F = 7.22, P = 0.010). Receiver operating characteristic (ROC) curve analyses confirmed flow measurement to be a useful predictor of fistula failure (area under ROC curve 0.91). The optimal threshold of 576 mL/min flow gave a sensitivity of 89% and a specificity of 81%. Measurement of access resistance was less useful in predicting failure (area under ROC curve 0.87). Measurement of fall in flow from the previous measurement was of no use (area under ROC curve 0.535).
  
  
  CONCLUSIONS
  On-line thermodilution measurement of flow within established native arteriovenous fistula is useful in surveillance and early prediction of fistula failure. Fistula flow <576 mL/min may indicate incipient native fistula failure, and should prompt further investigation.
authors.affiliation: Northern Territory Clinical School of Flinders University, Royal Darwin Hospital, Northern Territory, Australia. John.Treacy@nt.gov.au
authors.forename: P John
authors.initials: PJ
authors.lastname: Treacy
authors.forename: Joe L
authors.initials: JL
authors.lastname: Ragg
authors.forename: Paul
authors.initials: P
authors.lastname: Snelling
authors.forename: Paul
authors.initials: P
authors.lastname: Lawton
authors.forename: Helen
authors.initials: H
authors.lastname: Lammi
mesh_terms: D000328:Adult; D000368:Aged; D001166:Arteriovenous Shunt, Surgical; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012039:Regional Blood Flow; D006435:Renal Dialysis; D013815:Thermodilution; D013927:Thrombosis / Q000175:diagnosis* / Q000503:physiopathology* / Q000517:prevention & control; D014655:Vascular Resistance