title: Flow reduction in high-flow arteriovenous access using intraoperative flow monitoring.
abstract: OBJECTIVE
  This study used intraoperative monitoring of the access flow to evaluate the results of flow reduction in the management of high-flow arteriovenous access-related symptoms of distal ischemia and cardiac insufficiency.
  
  
  METHODS
  A retrospective study was conducted of 95 patients (78 with ischemia, 17 with cardiac failure) who underwent flow reduction between 1999 and 2005. A preoperatively measured access flow-volume rate > 800 mL/min for autogenous accesses (n = 77) and > 1200 mL/min for prosthetic accesses (n = 18) was the selection criterion for the use of a flow reduction procedure. Flow reduction was achieved using a spindle-like narrowing suture near the anastomosis and final placement of a polytetrafluoroethylene strip while a flow meter was used for intraoperatively measuring the access flow. The desired postoperative flow was 400 mL/min for autogenous and 600 mL/min for prosthetic accesses.
  
  
  RESULTS
  The mean preoperative access flow was 1469 +/- 633 mL/min in patients with ischemia and 2084 +/- 463 mL/min in patients with cardiac failure, without significant differences between access types. The flow was reduced to 499 +/- 175 mL/min for autogenous accesses and to 676 +/- 47 mL/min for prosthetic accesses. The mean follow-up was 25 months (range, 1 to 73 months). Complete long-term relief of symptoms was observed in 86% of patients with ischemia and in 96% of patients with cardiac failure. Reconstruction significantly increased the digital-brachial index (0.41 +/- 0.12 vs 0.74 +/- 0.11; P < .05) and mean distal arterial pressure (47 +/- 17 mm Hg vs 79 +/- 21 mm Hg; P < .05) in patients with ischemia. Primary patency rates were significantly better for reconstructed autogenous accesses compared with rates of prosthetic accesses (91% +/- 4% vs 58% +/- 12% at 12 months; 81% +/- 6% vs 41% +/- 14% at 36 months; P < .001). The low patency of reconstructed prosthetic accesses is due to the high thrombosis risk of accesses that have a flow < 700 mL/min.
  
  
  CONCLUSIONS
  Flow reduction using intraoperative access flow monitoring is an effective and durable technique allowing for the correction of distal ischemia and cardiac insufficiency in patients with a high-flow autogenous access. The desired postoperative access flow of 400 mL/min is not associated with an increased risk of thrombosis. Flow reduction of prosthetic access is as effective; however, a higher access flow than the desired 600 mL/min seems to be necessary to achieve an acceptable patency in prosthetic accesses.
authors.affiliation: Department of Vascular Surgery, Queen Elisabeth Hospital, Berlin, Germany. Juergen.Zanow@med.uni-jena.de
authors.forename: Juergen
authors.initials: J
authors.lastname: Zanow
authors.forename: Karen
authors.initials: K
authors.lastname: Petzold
authors.forename: Michael
authors.initials: M
authors.lastname: Petzold
authors.forename: Ulf
authors.initials: U
authors.lastname: Krueger
authors.forename: Hans
authors.initials: H
authors.lastname: Scholz
mesh_terms: D001158:Arteries / Q000503:physiopathology; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects*; D001783:Blood Flow Velocity; D001794:Blood Pressure; D019917:Blood Vessel Prosthesis Implantation; D002303:Cardiac Output, Low / Q000000981:diagnostic imaging / Q000209:etiology / Q000401:mortality / Q000503:physiopathology* / Q000601:surgery; D005121:Extremities / Q000098:blood supply*; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular; D006801:Humans; D007511:Ischemia / Q000000981:diagnostic imaging / Q000209:etiology / Q000401:mortality / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D012039:Regional Blood Flow; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome; D018615:Ultrasonography, Doppler, Color; D014654:Vascular Patency; D014656:Vascular Surgical Procedures