title: Platelet activation, coagulation activation and C-reactive protein in simultaneous samples from the vascular access and peripheral veins of haemodialysis patients.
abstract: BACKGROUND
  Most studies of haemodialysis (HD) patients compare venous blood samples from controls with samples from the vascular access (VA) of HD patients. We hypothesised that VA samples may be more prothrombotic compared with venous samples.
  
  
  METHODS
  Samples were taken simultaneously from the VA and the contralateral antecubital vein, from 26 patients immediately before HD. Platelet function was assessed by (1) flow cytometric measurement of P-selectin expression and fibrinogen binding (±ADP) and 2) Ultegra rapid platelet function assay. Plasma soluble P-selectin, von Willebrand factor antigen, high sensitivity C-reactive Protein (hs-CRP), thrombin-antithrombin III complex and D-dimer measured by ELISA.
  
  
  RESULTS
  Thrombin receptor activating peptide-induced platelet aggregation (P < 0.001) and hs-CRP (P < 0.001) were higher in VA compared with venous samples. Unstimulated platelet fibrinogen binding (P = 0.016) and ADP-stimulated P-selectin expression (P = 0.008) were lower in VA compared with venous samples. The significant difference in hsCRP persisted when patients taking and not taking antiplatelet therapy were analysed separately, but platelet activation remained significantly different only in the nonantiplatelet group.
  
  
  CONCLUSIONS
  There are statistically significant differences between sampling sites, although samples from the VA do not appear to be more pro-thrombotic. Future studies comparing HD patients with controls should ensure uniformity of sampling sites to prevent inaccurate conclusions being drawn.
authors: Department of Vascular Surgery, University of Aberdeen, Aberdeen Royal Infirmary, Aberdeen, UK. j.milburn@nhs.net
authors: J A
authors: JA
authors: Milburn
authors: I
authors: I
authors: Ford
authors: K
authors: K
authors: Cassar
authors: N
authors: N
authors: Fluck
authors: J
authors: J
authors: Brittenden
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006403:Hematologic Tests / Q000592:standards; D006801:Humans; D007249:Inflammation / Q000097:blood; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D006435:Renal Dialysis; D013927:Thrombosis / Q000097:blood*; D014841:von Willebrand Factor / Q000032:analysis / Q000378:metabolism
chemical_list: D015415:Biomarkers; D010975:Platelet Aggregation Inhibitors; D014841:von Willebrand Factor; D002097:C-Reactive Protein