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To determine whether repair of asymptomatic stenosis in arteriovenous fistula for hemodialysis can improve vascular access survival
DOI 10.1186/ISRCTN69115386
ClinicalTrials.gov identifier
EudraCT number
Public title To determine whether repair of asymptomatic stenosis in arteriovenous fistula for hemodialysis can improve vascular access survival
Scientific title To determine whether repair of asymptomatic stenosis in arteriovenous fistula for hemodialysis can improve vascular access survival: an open randomized comparative interventional trial
Acronym N/A
Serial number at source N/A
Study hypothesis We tested the hypothesis of whether elective repair of subclinical stenosis (i.e. in a well-functioning access capable of delivering adequate dialysis dose) in AVFs with a Qa>500 ml/min could decrease the risk of access failure (the composite of thrombosis and signs of impending thrombosis), improve access use-life, and be cost-effective by comparison with correcting stenosis only when it becomes hemodynamically significant due to the onset of dysfunction detected during dialysis, an otherwise explained decrease in the dose of dialysis delivered), or a Qa <400-500 ml/min, as recommended by the K/DOQI guidelines.
Lay summary Lay summary under review 1
Ethics approval Ethics Committee for Clinical Trials, University Hospital Integrated Verona [Comitato Etico per la Sperimentazione Clinica, Azienda Ospedaliera Universitaria Integrata Verona], 26.09.2006, ref: Prog. Number 1131
Study design Single-centre open randomized comparative interventional trial
Countries of recruitment Italy
Disease/condition/study domain Asymptomatic AVF stenosis
Participants - inclusion criteria 1. Age >18 years old, either sex
2. Hemodialysis patients with arteriovenous mature AVF with angiographically-proven significant (>50% reduction in vessel diameter) asymptomatic stenosis (i.e. in a well-functioning access capable of delivering a spKt/V >1.2 within a 4-hour period and no dialysis-related abnormalities) and a Qa >500 ml/min.
3. Able to provide an informed consent
Participants - exclusion criteria Any endovascular or surgical intervention in the 3 months prior to enrolment
Anticipated start date 01/10/2006
Anticipated end date 30/09/2013
Status of trial Completed
Patient information material
Target number of participants 80 subjects, equally distributed between the control and treatment arms.
Interventions In the control group, stenosis will be corrected. in response to access dysfunction or a Qa<400 ml/min.

In the treatment group, stenosis will be corrected electively within 2 weeks of enrolment, and imaging for restenosis (by angiography of duplex ultrasound) and re-stenosis repair during the follow-up are performed in cases of Qa<750 ml/min or a >25% drop in Qa. These Qa criteria were choosen because of their high sensitivity to detect stenosis in AVF in our experience [Tessitore et al. AJKD 2003, 42:331]

In both groups, stenosis will be repaired electively by percutaneous transluminal angioplasty (PTA) or surgery (a more proximal neo-anastomosis or a PTFE interposition graft): the choice of intervention was made case by case at discretion of and depending on the availability of the radiologist and the vascular surgeon with the view to correcting stenosis without any major reduction in the venous capital available for puncture [Tessitore et al CJASN 2006; 1:448].

In both groups, thrombectomy was performed depending on the availability of the attending radiologist and vascular surgeon by manual catheter-directed thrombo-aspiration or surgical revision, with the aim of declotting thrombosed AVF within 48 hour of its detection.
Primary outcome measure(s) 1. Access failure, the composite of thrombosis or preemptive intervention triggered by signs of impending thrombosis (a Qa<300 ml/min, access recirculation, or a >60 ml/min drop of the prescribed Qb) Tessitore et al. AJKD 2003, 42:331]
2. Access abandonment, because patency could not be restored after a thrombotic episode (because the access was considered unsalvageable or thrombectomy was unsuccessful), or a patent access was unsuitable for cannulation or unable to sustain adeguate dialysis (i.e. a spKt/V<1.0 within a 4-hour hemodialysis session).
Secondary outcome measure(s) Direct cost of access treatment, including all expenses for surveillance and imaging during the follow-up, elective endovascular and surgical intervention, thrombectomy, placement of a new access or a cuffed and uncuffed temporary central venous catheter, and hospitalization.
Sources of funding Division of Nephrology and Dialysis Azienda Ospedaliera Universitaria Integrata Verona (Italy)
Trial website
Contact name Dr  Nicola  Tessitore
  Address Piazzale LA Scuro 10
  City/town Verona
  Zip/Postcode 37133
  Country Italy
  Tel +39 0458124652
  Fax +39 0458124687
  Email nicola.tessitore@ospedaleuniverona.it
Sponsor Division of Pediatric Nephrology and Dialysis Unit (UOC Nefrologia e Dialisi dU) (Italy)
  Address Piazzale Stefani 1
  City/town Verona
  Zip/Postcode 37126
  Country Italy
  Tel +39 045 8122528
  Fax +39 045 8027311
  Email direzionenefrovr@virgilio.it
Date applied 14/01/2013
Last edited 31/01/2013
Date ISRCTN assigned 31/01/2013
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