title: Preemptive Correction of Arteriovenous Access Stenosis: A Systematic Review and Meta-analysis of Randomized Controlled Trials.
abstract: BACKGROUND
  Preemptive correction of a stenosis in an arteriovenous (AV) access (fistula or graft) that is adequately providing hemodialysis (functional AV access) may prolong access survival as compared to waiting for signs of access dysfunction to intervene (deferred salvage). However, the evidence in support of preemptive intervention is controversial. We evaluated benefits and harms of preemptive versus deferred correction of AV access stenosis.
  
  
  METHODS
  Systematic review and meta-analysis of randomized controlled trials.
  
  
  METHODS
  Adults receiving hemodialysis by a functional AV access.
  
  
  METHODS
  We searched the Cochrane Kidney and Transplant Specialised Register and EMBASE to October 15, 2015.
  
  
  METHODS
  Active access surveillance (flow measurement and Doppler or venous pressure) and preemptive correction of a newly identified stenosis versus routine clinical monitoring and deferred salvage, or preemptive correction of a known stenosis versus deferred salvage.
  
  
  RESULTS
  Access loss (primary outcome) and thrombosis (overall and by access type), infection, mortality, hospitalization, and access-related procedures.
  
  
  RESULTS
  We included 14 trials (1,390 participants; follow-up, 6-38 months). Relative to deferred salvage, preemptive correction of AV access stenosis had a nonsignificant effect on risk for access loss (risk ratio [RR], 0.81; 95% CI, 0.65-1.02; I(2)=0%) and a significant effect on risk for thrombosis (RR, 0.79; 95% CI, 0.65-0.97; I(2)=30%). Treatment effects were larger in fistulas than in grafts for both risk for access loss (subgroup difference, P=0.05) and risk for thrombosis (subgroup difference, P=0.002). Results were heterogeneous or imprecise for mortality, rates of access-related infections or procedures, and hospitalization.
  
  
  CONCLUSIONS
  Small number and size of primary studies limited analysis power.
  
  
  CONCLUSIONS
  Preemptive stenosis correction in a functional AV access does not improve access longevity. Although preemptive stenosis correction may be promising in fistulas, existing evidence is insufficient to guide clinical practice and health policy.
authors.affiliation: Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Canada; Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Canada. Electronic address: pravani@ucalgary.ca.
authors.forename: Pietro
authors.initials: P
authors.lastname: Ravani
authors.affiliation: Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Canada; Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Canada.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Quinn
authors.affiliation: Department of Medicine, University of Toronto, Toronto, Canada.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Oliver
authors.affiliation: Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Canada.
authors.forename: Divya J
authors.initials: DJ
authors.lastname: Karsanji
authors.affiliation: Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Canada; Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Canada.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: James
authors.affiliation: Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Canada.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: MacRae
authors.affiliation: Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand.
authors.forename: Suetonia C
authors.initials: SC
authors.lastname: Palmer
authors.affiliation: Cochrane Kidney and Transplant, Centre for Kidney Research, The Children's Hospital at Westmead, Westmead, Australia; Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy; Diaverum Academy, Bari, Italy; Diaverum Medical Scientific Office, Lund, Sweden; Sydney School of Public Health, University of Sydney, Sydney, Australia.
authors.forename: Giovanni F M
authors.initials: GF
authors.lastname: Strippoli
mesh_terms: D000328:Adult; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects / Q000379:methods; D057186:Comparative Effectiveness Research; D003251:Constriction, Pathologic / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D061345:Early Medical Intervention / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D017063:Outcome Assessment, Health Care; D011183:Postoperative Complications / Q000503:physiopathology / Q000517:prevention & control; D016032:Randomized Controlled Trials as Topic; D006435:Renal Dialysis / Q000295:instrumentation / Q000379:methods; D013927:Thrombosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D014654:Vascular Patency; D057832:Watchful Waiting / Q000379:methods / Q000706:statistics & numerical data
keywords: Hemodialysis access; access angioplasty; access loss; access salvage; access screening; access surveillance; access thrombosis; arteriovenous fistula; arteriovenous graft; patency; pre-emptive stenosis correction; renal replacement therapy; systematic review; vascular access