title: Detection of vascular access stenosis by measurement of access blood flow from ionic dialysance.
abstract: OBJECTIVE
  The measurement of the vascular access blood flow rate (Q(a)) in chronic hemodialyzed patients was proposed to predict access thrombosis. We have recently presented a new method based on the measurements of ionic dialysance at normal and reversed positions of the blood lines. We evaluate the reliability of the measurement of Q(a) by this method in detecting significant access stenoses.
  
  
  METHODS
  Twenty-five patients on chronic hemodialysis and having a vascular access cannulated with two needles were studied. The Q(a) was evaluated by the Diascan ionic dialysance (Q(a-id)) method and by the ultrasound dilution technique (Q(a-us); Transonic) during the same dialysis session. The measurements were available for 23 patients. In addition, the patients had ultrasonography of their fistula followed by angiography, if a stenosis was detected.
  
  
  RESULTS
  Q(a-id) and Q(a-us) were not significantly different, showing a difference in Q(a) at 32 +/- 469 ml/min. Q(a-id) was significantly different between patients with or without stenosis (508 +/- 241 vs. 1,125 +/- 652 ml/min, p < 0.05). Among patients with a Q(a) <500 ml/min by Q(a-id), 5 had a stenosis detected by ultrasonography (sensitivity 83%), and 3 had no stenosis (false-positive rate 18%). Of these 3 patients, 2 had a thrombotic event at 1 and 3 months, suggesting that a more sensitive detection of stenosis for this range of Q(a) is needed and that a Q(a) <500 ml/min has a higher power to predict thromboses than a stenosis by ultrasonography.
  
  
  CONCLUSIONS
  The measurement of the access flow rate by the Q(a-id) method has a clinical relevance to the detection of vascular access stenosis. An intervention program based on the Q(a-id) has to be evaluated.
authors.affiliation: Department of Nephrology, Pitié-Salpêtrière Hospital, Paris, France. lucile.mercadal@psl.ap-hop-paris.fr
authors.forename: Lucile
authors.initials: L
authors.lastname: Mercadal
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Challier
authors.forename: Philippe
authors.initials: P
authors.lastname: Cluzel
authors.forename: Abdelaziz
authors.initials: A
authors.lastname: Hamani
authors.forename: Hacène
authors.initials: H
authors.lastname: Boulechfar
authors.forename: Zhora
authors.initials: Z
authors.lastname: Boukhalfa
authors.forename: Hassane
authors.initials: H
authors.lastname: Izzedine
authors.forename: Nader
authors.initials: N
authors.lastname: Bassilios
authors.forename: Benoît
authors.initials: B
authors.lastname: Barrou
authors.forename: Gilbert
authors.initials: G
authors.lastname: Deray
authors.forename: Thierry
authors.initials: T
authors.lastname: Petitclerc
mesh_terms: D001159:Arterio-Arterial Fistula / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging; D001775:Blood Circulation; D001783:Blood Flow Velocity; D002408:Catheters, Indwelling / Q000009:adverse effects*; D003251:Constriction, Pathologic / Q000175:diagnosis*; D015314:Dialysis Solutions; D006083:Graft Occlusion, Vascular / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging; D006801:Humans; D008955:Models, Cardiovascular; D011237:Predictive Value of Tests; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods; D013927:Thrombosis / Q000175:diagnosis / Q000209:etiology; D014463:Ultrasonography
chemical_list: D015314:Dialysis Solutions