title: Coagulation and complement activation.
abstract: The purpose of this investigation was to assess the effect of heparin coating of a new stent construction (Stent Graft, Jomed Implantate GmbH, Germany) on platelet and coagulation activity.
  
  
  METHODS
  Stent grafts with an ePTFE membrane interfoliated between two stents were deployed in tubings to form Chandler loops. Fresh human blood with a low concentration of heparin was rotated for 1 h, then collected and used for measurements of platelet number, thrombin-antithrombin complex (TAT), CD11b, C3a and C5b-9. There were five study groups: Group 1, conventional unmodified stents (n = 8); Group 2, untreated stent grafts (n = 8); Group 3, heparin-coated stents and untreated membrane (n = 7); Group 4, heparin-coated stents and membrane (n = 8); Group 5, heparin-coated PVC tubings with no stents (n = 8).
  
  
  RESULTS
  There was a significant drop in platelet count, increase in TAT-values and CD11b expression in Groups 1-3 but not in Group 4 compared to Group 5. Examination by scanning electron microscopy revealed extensive activation on non-modified stents but almost no deposition of thrombotic material on heparin-modified stent grafts.
  
  
  CONCLUSIONS
  With unmodified stents and membrane there were signs of significant activation of platelets and coagulation. In contrast, the heparin-coated stent graft induced much less alterations, indicating improved blood compatibility.
authors.affiliation: Division of Cardiology, Medical Center Hospital, Orebro, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Christensen
authors.forename: R
authors.initials: R
authors.lastname: Larsson
authors.forename: H
authors.initials: H
authors.lastname: Emanuelsson
authors.forename: G
authors.initials: G
authors.lastname: Elgue
authors.forename: A
authors.initials: A
authors.lastname: Larsson
mesh_terms: D001777:Blood Coagulation; D003167:Complement Activation; D006493:Heparin; D006801:Humans; D007124:Immunoenzyme Techniques; D008855:Microscopy, Electron, Scanning; D018375:Neutrophil Activation; D015539:Platelet Activation; D010976:Platelet Count; D015607:Stents
chemical_list: D006493:Heparin