title: A systematic review and meta-analysis of systemic intraoperative anticoagulation during arteriovenous access formation for dialysis.
abstract: OBJECTIVE
  Surgical arteriovenous fistula (AVF) or graft (AVG) is preferred to a central venous catheter for dialysis access. Surgical access may suffer thrombosis early after placement and systemic anticoagulation during surgical access formation may increase patency rates but would be expected to increase bleeding-related complications. A systematic review and meta-analysis of randomised controlled trials was conducted to examine the impact of systemic anticoagulation on access surgery perioperative bleeding and patency rates.
  
  
  METHODS
  We included randomised controlled trials testing systemic anticoagulation during access formation versus a control group without systemic anticoagulation reporting bleeding complications and access patency. Medline, Embase, CENTRAL and CINAHL were searched up to March 2015. Risk of bias was assessed using the Cochrane risk of bias tool and the Jadad score. Meta-analysis was performed using Cochrane Revman® software.
  
  
  RESULTS
  Searches identified 445 reports of which four randomised studies involving 411 participants were included. Three studies pertained to AVF only and one included both AVF and AVG. Systemic anticoagulation led to increased bleeding events in all access [four trials; risk ratio (RR) 7.18; confidence interval (CI), 2.41 to 21.38; p<0.001]. Patency was not improved for all access (four trials; RR, 0.64; CI, 0.37 to 1.09; p = 0.10) but was improved when AVF analysed alone (three trials; RR, 0.57; CI, 0.33 to 0.97; p = 0.04).
  
  
  CONCLUSIONS
  The use of intraoperative systemic anticoagulation during access formation is associated with a highly significant increased risk of bleeding-related complications. A significant improvement in AVF patency was seen, though not when AVF and AVG were analysed together.
authors.affiliation: Academic Vascular Surgery Unit, Hull Royal Infirmary, Hull, Humberside - UK.
authors.forename: George E
authors.initials: GE
authors.lastname: Smith
authors.affiliation: Academic Vascular Surgery Unit, Hull Royal Infirmary, Hull, Humberside - UK.
authors.forename: Panos
authors.initials: P
authors.lastname: Souroullos
authors.affiliation: Academic Vascular Surgery Unit, Hull Royal Infirmary, Hull, Humberside - UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Cayton
authors.affiliation: Academic Vascular Surgery Unit, Hull Royal Infirmary, Hull, Humberside - UK.
authors.forename: Amy
authors.initials: A
authors.lastname: Harwood
authors.affiliation: Academic Vascular Surgery Unit, Hull Royal Infirmary, Hull, Humberside - UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Carradice
authors.affiliation: Academic Vascular Surgery Unit, Hull Royal Infirmary, Hull, Humberside - UK.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Chetter
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects; D016063:Blood Loss, Surgical; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects; D016009:Chi-Square Distribution; D004334:Drug Administration Schedule; D006083:Graft Occlusion, Vascular / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D006801:Humans; D007430:Intraoperative Care; D016017:Odds Ratio; D019106:Postoperative Hemorrhage / Q000139:chemically induced; D006435:Renal Dialysis; D012307:Risk Factors; D013927:Thrombosis / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D016896:Treatment Outcome; D014654:Vascular Patency
chemical_list: D000925:Anticoagulants