title: The anastomosis angle does change the flow fields at vascular end-to-side anastomoses in vivo.
abstract: OBJECTIVE
  The purpose of this article was to study the influence of the anastomosis angle on the flow fields at end-to-side anastomoses in vivo.
  
  
  METHODS
  Polyurethane grafts of similar internal diameter to that of the abdominal aorta (8 mm) were implanted from the suprarenal to the infrarenal level in 10 pigs. Three angles of standardized distal end-to-side anastomoses (90 degrees, 45 degrees, and 15 degrees) were studied. The anatomic position of the anastomoses was constant, the proximal outflow segment was occluded, and the flow rate through the graft was controlled. Flow visualization was accomplished by a color-flow Doppler ultrasound system.
  
  
  RESULTS
  The angulation was reproduced within 10%. Gross hemodynamic parameters were stable, and the similarity parameters were typical for peripheral bypasses (mean Reynold's number is 424 and Womersley's parameter is 5.9). The flow fields were clearly dependent on the anastomosis angle. A zone of recirculation (approximately 5% of the flow area), extending from the toe to one diameter downstream, was found in the 45-degree and 90-degree anastomoses. No flow disturbances were detected at the toe and one diameter downstream with an anastomosis angle of 15 degrees. At the heel different recirculating flow patterns were found in the different anastomoses.
  
  
  CONCLUSIONS
  The anastomosis angle does change the flow fields at vascular end-to-side anastomoses in vivo.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Skejby Sygehus, Aarhus University Hospital, Denmark.
authors.forename: N H
authors.initials: NH
authors.lastname: Staalsen
authors.forename: M
authors.initials: M
authors.lastname: Ulrich
authors.forename: J
authors.initials: J
authors.lastname: Winther
authors.forename: E M
authors.initials: EM
authors.lastname: Pedersen
authors.forename: T
authors.initials: T
authors.lastname: How
authors.forename: H
authors.initials: H
authors.lastname: Nygaard
mesh_terms: D000714:Anastomosis, Surgical / Q000379:methods*; D000818:Animals; D001011:Aorta / Q000000981:diagnostic imaging / Q000502:physiology / Q000601:surgery*; D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis; D006439:Hemodynamics; D018056:Hemorheology; D013552:Swine; D018615:Ultrasonography, Doppler, Color