title: Diabetes and distal access location are associated with higher wall shear rate in feeding artery of PTFE grafts.
abstract: BACKGROUND
  Surgical creation of permanent vascular access for haemodialysis leads to considerable haemodynamic changes. They could be implicated in the pathogenesis of access complications, which limit access survival, especially in diabetics. Physiologically, the relation between arterial diameter and blood velocity is maintained by wall shear stress (WSS), which is directly related to both blood viscosity and wall shear rate (WSR = blood velocity/internal diameter). Because of methodological difficulties, WSR is used as a measure of WSS. Extremely high values of WSS might induce hypercoagulable states, which might contribute to access thrombosis. We performed a study, which was aimed to (i) describe WSR values in feeding arteries of various polytetrafluoroethylene access types and (ii) prove that diabetic patients have higher WSR than non-diabetics.
  
  
  METHODS
  A linear-array 11 MHz probe of SONOS 5500 (Phillips, USA) was used to obtain blood velocity and internal diameter in the feeding arteries of radial or brachial polytetrafluoroethylene grafts. WSR was calculated as 4 x blood velocity/internal diameter. We compared observed values of WSR according to feeding artery (radial vs brachial artery) and according to diabetic status using unpaired t-test.
  
  
  RESULTS
  We included 106 patients (58 non-diabetic and 48 diabetic) in the study. WSR was significantly higher in radial arteries compared with brachial arteries independent of diabetes status. Diabetic subjects had significantly higher WSR in both radial and brachial arteries.
  
  
  CONCLUSIONS
  Diabetes mellitus and distal vascular access creation are associated with higher WSR in the feeding artery. This could be of relevance in the pathogenesis of access complications, e.g. thrombosis, and thus lower patency rates in diabetic patients.
authors.affiliation: Third Department of Internal Medicine, General University Hospital, Charles University, U Nemocnice 1, Prague 2, 128 08, Czech Republic. Vladimir.Tuka@vfn.cz
authors.forename: Vladimir
authors.initials: V
authors.lastname: Tuka
authors.forename: Marcela
authors.initials: M
authors.lastname: Slavikova
authors.forename: Jaroslava
authors.initials: J
authors.lastname: Svobodova
authors.forename: Jan
authors.initials: J
authors.lastname: Malik
mesh_terms: D000368:Aged; D001158:Arteries / Q000473:pathology / Q000503:physiopathology / Q000637:transplantation*; D001166:Arteriovenous Shunt, Surgical; D001809:Blood Viscosity; D002339:Carotid Arteries / Q000473:pathology / Q000503:physiopathology / Q000637:transplantation; D003920:Diabetes Mellitus / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D018056:Hemorheology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011138:Polytetrafluoroethylene / Q000627:therapeutic use*; D017534:Radial Artery / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D013314:Stress, Mechanical
chemical_list: D011138:Polytetrafluoroethylene