title: Surveillance of arteriovenous hemodialysis access: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Hemodialysis centers regularly survey arteriovenous (AV) accesses for signs of dysfunction. In this review, we synthesize the available evidence to determine to what extent proactive vascular access monitoring affects the incidence of AV access thrombosis and abandonment compared with clinical monitoring.
  
  
  METHODS
  We searched electronic databases (MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science, and SCOPUS) and sought references from experts, bibliographies of included trials, and articles that cited included studies. Two reviewers independently assessed trial quality and extracted data. We used random effects meta-analysis to estimate the pooled relative risk (RR) and 95% confidence interval (CI) across studies and conducted subgroup analyses to explain heterogeneity. The I(2) statistic was used to assess heterogeneity of treatment effect among trials.
  
  
  RESULTS
  Nine studies (1363 patients) compared a strategy of surveillance vs clinical monitoring. A vascular intervention to maintain or restore patency was provided to both groups if needed. Surveillance followed by intervention led to a nonsignificant reduction of the risk of access thrombosis (RR, 0.82; 95% CI, 0.58-1.16; I(2) = 37%) and access abandonment (RR, 0.80; 95% CI, 0.51-1.25; I(2) = 60%). Three studies (207 patients) compared the effect of vascular interventions vs observation in patients with abnormal surveillance result. Vascular interventions after an abnormal AV access surveillance led to a significant reduction of the risk of access thrombosis (RR, 0.53; 95% CI, 0.36-0.76) and a nonsignificant reduction of the risk of access abandonment (RR, 0.76; 95% CI, 0.43-1.37).
  
  
  CONCLUSIONS
  Very low quality evidence yielding imprecise results suggests a potentially beneficial effect of AV access surveillance followed by interventions to restore patency. This inference, however, is weak and will require randomized trials of AV access surveillance vs clinical monitoring for rejection or confirmation.
authors.affiliation: Division of Nephrology, Knowledge and Encounter Research Unit, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: Edward T
authors.initials: ET
authors.lastname: Casey
authors.forename: M Hassan
authors.initials: MH
authors.lastname: Murad
authors.forename: Adnan Z
authors.initials: AZ
authors.lastname: Rizvi
authors.forename: Anton N
authors.initials: AN
authors.lastname: Sidawy
authors.forename: Martina M
authors.initials: MM
authors.lastname: McGrath
authors.forename: Mohamed B
authors.initials: MB
authors.lastname: Elamin
authors.forename: David N
authors.initials: DN
authors.lastname: Flynn
authors.forename: Finnian R
authors.initials: FR
authors.lastname: McCausland
authors.forename: Danny H
authors.initials: DH
authors.lastname: Vo
authors.forename: Ziad
authors.initials: Z
authors.lastname: El-Zoghby
authors.forename: Audra A
authors.initials: AA
authors.lastname: Duncan
authors.forename: Michal J
authors.initials: MJ
authors.lastname: Tracz
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Erwin
authors.forename: Victor M
authors.initials: VM
authors.lastname: Montori
mesh_terms: D001166:Arteriovenous Shunt, Surgical / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D007676:Kidney Failure, Chronic / Q000628:therapy; D011183:Postoperative Complications / Q000453:epidemiology; D006435:Renal Dialysis / Q000379:methods* / Q000706:statistics & numerical data; D014656:Vascular Surgical Procedures / Q000592:standards