title: Timing of first cannulation and vascular access failure in haemodialysis: an analysis of practice patterns at dialysis facilities in the DOPPS.
abstract: BACKGROUND
  Optimal waiting time before first use of vascular access is not known.
  
  
  METHODS
  Two practices-first cannulation time for fistulae and grafts, and blood flow rate-were examined as potential predictors of vascular access failure in the Dialysis Outcomes and Practice Patterns Study (DOPPS). Access failure (defined as time to first failure or first salvage intervention) was modelled using Cox regression.
  
  
  RESULTS
  Among 309 haemodialysis facilities, 2730 grafts and 2154 fistulae were studied. For grafts, first cannulation typically occurred within 2-4 weeks at 62% of US, 61% of European and 42% of Japanese facilities. For fistulae, first cannulation occurred <2 months after placement in 36% of US, 79% of European and 98% of Japanese facilities. Overall, the relative risk (RR) of graft failure in Europe was lower compared with the USA (RR = 0.69, P = 0.04). The RR of graft failure (reference group = first cannulation at 2-3 weeks) was 0.84 with first cannulation at <2 weeks (P = 0.11), 0.94 with first cannulation at 3-4 weeks (P = 0.48) and 0.93 with first cannulation at >4 weeks (P = 0.48). The RR of fistula failure was 0.72 with first cannulation at <4 weeks (P = 0.08), 0.91 at 2-3 months (P = 0.43) and 0.87 at >3 months (P = 0.31) (reference group = first cannulation at 1-2 months). Facility median blood flow rate was not a significant predictor of access failure.
  
  
  CONCLUSIONS
  Earlier cannulation of a newly placed vascular access at the haemodialysis facility level was not associated with increased risk of vascular access failure. Potential for confounding due to selection bias cannot be excluded, implying the importance of clinical judgement in determining time to first use of vascular access.
authors.affiliation: Kidney Epidemiology and Cost Center, University of Michigan, 315 W. Huron, Suite 240, Ann Arbor, MI 48103, USA. rsaran@umich.edu
authors.forename: Rajiv
authors.initials: R
authors.lastname: Saran
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Dykstra
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Pisoni
authors.forename: Takashi
authors.initials: T
authors.lastname: Akiba
authors.forename: Tadao
authors.initials: T
authors.lastname: Akizawa
authors.forename: Bernard
authors.initials: B
authors.lastname: Canaud
authors.forename: Kenneth
authors.initials: K
authors.lastname: Chen
authors.forename: Luis
authors.initials: L
authors.lastname: Piera
authors.forename: Akira
authors.initials: A
authors.lastname: Saito
authors.forename: Eric W
authors.initials: EW
authors.lastname: Young
mesh_terms: D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects*; D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis / Q000009:adverse effects*; D002404:Catheterization / Q000009:adverse effects*; D005260:Female; D006083:Graft Occlusion, Vascular / Q000209:etiology; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011364:Professional Practice; D011446:Prospective Studies; D011475:Prosthesis Failure; D006435:Renal Dialysis / Q000295:instrumentation*; D013997:Time Factors; D014654:Vascular Patency