title: A randomized controlled trial of blood flow and stenosis surveillance of hemodialysis grafts.
abstract: BACKGROUND
  It is widely accepted that hemodialysis graft surveillance combined with correction of stenosis reduces thrombosis and prolongs graft survival. Nevertheless, few randomized controlled trials have evaluated this approach.
  
  
  METHODS
  In this randomized controlled trial, 101 patients were assigned to control, flow (Qa), or stenosis groups, and were followed for up to 28 months. All patients had monthly Qa measured by ultrasound dilution and quarterly percent stenosis measured by duplex ultrasound. Referral for angiography was based on the following criteria: (1) control group (N = 34), clinical criteria; (2) flow group (N = 32), Qa <600 mL/min or clinical criteria; and (3) stenosis group (N = 35), stenosis>50% or clinical criteria. Stenosis >or=50% during angiography was corrected by preemptive percutaneous transluminal angioplasty (PTA).
  
  
  RESULTS
  The preemptive PTA rate in the control group (0.22/patient year) was two thirds the rate in the flow group (0.34/patient year), and was highest in the stenosis group (0.65/patient year, P < 0.01). The percentage of grafts that thrombosed was similar in the control (47%) and flow groups (53%), but reduced in the stenosis group (29%, P = 0.10). Two-year graft survival was similar in the control (62%), flow (60%), and stenosis groups (64%) (P = 0.89).
  
  
  CONCLUSIONS
  Qa and stenosis surveillance were not associated with improved graft survival, although thrombosis was reduced in the stenosis group. The most important factors in this result may be that monthly Qa and quarterly stenosis measurements were not accurate or timely indicators of risk of thrombosis or progressive stenosis. This study does not support the concept that Qa or stenosis surveillance are superior to aggressive clinical monitoring.
authors.affiliation: Interventional Nephrology Section, Division of Nephrology and Hypertension, Department of Medicine, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA.
authors.forename: Sunanda J
authors.initials: SJ
authors.lastname: Ram
authors.forename: Jack
authors.initials: J
authors.lastname: Work
authors.forename: Gloria C
authors.initials: GC
authors.lastname: Caldito
authors.forename: J Mark
authors.initials: JM
authors.lastname: Eason
authors.forename: Aslam
authors.initials: A
authors.lastname: Pervez
authors.forename: William D
authors.initials: WD
authors.lastname: Paulson
mesh_terms: D000800:Angioplasty, Balloon; D001775:Blood Circulation; D001808:Blood Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000637:transplantation*; D016022:Case-Control Studies; D003251:Constriction, Pathologic; D005260:Female; D006085:Graft Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D006435:Renal Dialysis; D013927:Thrombosis / Q000517:prevention & control*; D018616:Ultrasonography, Doppler, Duplex