title: Improved patency of prosthetic arteriovenous grafts with an acute anastomotic angle and flow diffuser.
abstract: OBJECTIVE
  Conventional end-to-side anastomosis to establish venous outflow for prosthetic arteriovenous grafts often requires operative patch angioplasty within 1 year because of venous stenosis. Rather than conventional venous anastomosis, a modified end-to-side anastomosis at a 15-degree angle with a flow diffuser was constructed. Such diffusers allow decreased flow velocity and increased pressure, inhibiting boundary layer separation.
  
  
  METHODS
  Ten brachial artery to axillary vein 6 mm straight se-polytetrafluoroethylene prosthetic arteriovenous grafts were created with this technique. Patients included 6 men and 4 women (mean age, 66.4 years; range, 54-80 years), all with renal failure and a history of diabetes. The degree of stenosis at the venous anastomosis was determined with duplex scanning at intervals of 6 months. Analysis of survival and cumulative primary patency estimates were determined with the Kaplan-Meier method.
  
  
  RESULTS
  Primary cumulative patency estimate of 100% for the modified group at 18 and 24 months was significantly greater than that for age-matched historic control fistulas with the conventional end-to-side anastomosis (n = 20): 18 months, 32%; 24 months, 32% (P <.05). Although venous stenosis could not be quantitated for thrombosed conventional fistulas, modified anastomoses had minimal stenosis at 24 months: mean area reduction, 30% (range, 20%-45%).
  
  
  CONCLUSIONS
  Incorporation of a flow diffuser and a 15-degree anastomotic angle significantly increases patency of prosthetic brachial artery to axillary vein grafts.
authors.affiliation: Section of Vascular Surgery, Mayo Clinic, Jacksonville, FL 32244, USA. hakaim.albert@mayo.edu
authors.forename: Albert G
authors.initials: AG
authors.lastname: Hakaim
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Nalbandian
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Heller
authors.forename: Arun C
authors.initials: AC
authors.lastname: Chowla
authors.forename: W Andrew
authors.initials: WA
authors.lastname: Oldenburg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000714:Anastomosis, Surgical / Q000295:instrumentation; D001166:Arteriovenous Shunt, Surgical / Q000295:instrumentation*; D001367:Axillary Vein / Q000502:physiology / Q000601:surgery; D001783:Blood Flow Velocity / Q000502:physiology*; D001807:Blood Vessel Prosthesis; D001916:Brachial Artery / Q000502:physiology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D051437:Renal Insufficiency / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D016019:Survival Analysis; D016896:Treatment Outcome; D014654:Vascular Patency / Q000502:physiology*