title: Color doppler ultrasonography imaging to guide transluminal angioplasty of venous stenosis.
abstract: BACKGROUND
  The objective of access surveillance is the early recognition of dysfunction in order to be able to correct the stenosis by angioplasty or surgery before access thrombosis occurs. The advent of color Doppler imaging has enabled studies of color Doppler ultrasonography (CDU) for the guidance of percutaneous transluminal angioplasty (PTA). The aim of the present study was to investigate whether color Doppler imaging alone can be safely and effectively used to diagnose vascular graft access stenoses and guide subsequent PTA.
  
  
  METHODS
  Using the ultrasound velocity dilution method, we measured access blood flow (Qa) during the first hour of hemodialysis every month in patients with grafts as vascular access. When the decrease in Qa from the baseline value was 40% or more, CDU was performed and immediately followed by PTA in the presence of a stenosis of more than 50%. The Qa was then measured during the first dialysis after PTA and one month later. Repeated-measure analysis of variance was applied to evaluate the early and late (after one month) effect of PTA.
  
  
  RESULTS
  Twelve PTAs were performed under CDU guidance in nine patients and led to the elimination of the stenosis or its reduction (two cases). The mean Qa was 809 +/- 263 mL/min at baseline, 468 +/- 153 before PTA, and 820 +/- 281 after PTA. The difference between the pre-PTA and post-PTA values was highly significant (P < 0.001), and the mean value after PTA was not different from baseline (P = 0.672). There were no relevant complications directly related to the procedure.
  
  
  CONCLUSIONS
  The CDU procedure is effective for the diagnosis of vascular access stenosis and as a guide during the PTA procedure. It could improve stenosis screening by avoiding the risks of exposure to ionizing radiation and of adverse reactions to contrast media.
authors.affiliation: Department of Nephrology and Dialysis, and Department of Radiology, Hospital of Lecco, Lecco, Italy. nefrologia@ospedale.lecco.it
authors.forename: G
authors.initials: G
authors.lastname: Bacchini
authors.forename: A
authors.initials: A
authors.lastname: Cappello
authors.forename: V
authors.initials: V
authors.lastname: La Milia
authors.forename: S
authors.initials: S
authors.lastname: Andrulli
authors.forename: F
authors.initials: F
authors.lastname: Locatelli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D000800:Angioplasty, Balloon / Q000379:methods*; D001166:Arteriovenous Shunt, Surgical; D003251:Constriction, Pathologic; D005260:Female; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging* / Q000628:therapy*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D006435:Renal Dialysis; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy; D018615:Ultrasonography, Doppler, Color