title: Quantitative analysis of heparin retention on heparin bonded knitted Dacron grafts after exposure to shear stress in vitro.
abstract: OBJECTIVE
  To analyse the quantity of heparin retention on heparin bonded collagen coated knitted Dacron grafts (HCD) and heparin bonded knitted Dacron grafts without interluminal collagen coating (HD) after they had been exposed to shear stress in an artificial circulation model.
  
  
  METHODS
  A comparative study.
  
  
  METHODS
  University Hospital, Department of Surgery.
  
  
  METHODS
  HCD grafts were exposed to shear stress during 2, 24, 48, and 168 hours, and HD grafts during 1, 2, 3 and 4 weeks. Heparin retention on the graft walls was determined by a method based on the measurements of total sugars.
  
  
  RESULTS
  HCD grafts showed no loss of heparin from the graft-surface when exposed to a flow of 200 ml/min up to 168 hrs. HD grafts demonstrated an initial loss of heparin from 8 mg/g to 3 mg/g/graft-segment within one week after which the level was stable during the remaining three weeks.
  
  
  CONCLUSIONS
  Based on the present experimental setting it seems reasonable to conclude that the heparin-collagen layer remains stable but heparin alone is partly washed out by shear stress. To measure the release of heparin under the influence of the bloodstream including mechanisms for the slow degradation of collagen, a more sensitive method for heparin analysis is required.
authors.affiliation: Department of Surgery, Lund University, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Swartbol
authors.forename: L
authors.initials: L
authors.lastname: Norgren
mesh_terms: D001807:Blood Vessel Prosthesis; D003094:Collagen; D006493:Heparin / Q000008:administration & dosage / Q000032:analysis*; D008954:Models, Biological; D011093:Polyethylene Terephthalates; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D011093:Polyethylene Terephthalates; D006493:Heparin; D003094:Collagen