Effect of dextran and enoxaparin on early ePTFE graft thrombogenicity in sheep.
OBJECTIVE
To evaluate the effect of low molecular weight heparin (LMWH), dextran 70 and their combination on platelet adhesion and fibrinogen uptake in ePTFE grafts in an experimental sheep model.


METHODS
Prospective open study.


METHODS
Animal Laboratory of a University Hospital.


METHODS
Early thrombogenicity of ePTFE grafts was studied after interposition in the two common carotid arteries of 40 adult sheep. The animals received one of four different treatment regimens in a double blind randomised way: enoxaparin and polygeline, saline and dextran 70, enoxaparin and dextran 70 or saline and polygeline (control). The substances were administered i.v. with a total dose of 73 antifactor-Xa U/kg for enoxaparin and 1.0 g/kg for dextran 70. Polygeline and saline were used as placebo substances in equivalent volumes. On one side (random allocation) the carotid blood flow was restricted to 25 ml/min, on the other side it was left unrestricted.


METHODS
The following variables were studied: 1) fibrinogen uptake; 2) platelet uptake; 3) early graft patency; 4) blood flow in patient grafts; 5) visible presence of graft thrombus; 6) thrombus weight.


RESULTS
The results verified the importance of adequate blood flow as only 30% of grafts with restricted blood flow in the control group were patent compared with 80% of those with unrestricted blood flow (p = 0.038). Dextran 70, enoxaparin and the combination of the two increased early graft patency (p < 0.05) and reduced thrombus weights (p < 0.05) in grafts with restricted blood flow. The relative number of grafts with thrombus free surface was increased in the unrestricted blood flow situation.


CONCLUSIONS
Dextran 70 and enoxaparin appeared to be equally effective in decreasing fibrinogen and platelet uptake in the grafts. Their combination was not significantly more effective although there was a favourable trend.
Matthiasson
S E
SE
Department of Surgery, Lund University, University Hospital MAS, Malmö, Sweden.
Bergqvist
D
D
Lundell
A
A
Lindblad
B
B
D000818:Animals; D001807:Blood Vessel Prosthesis; D017536:Carotid Artery, Common / Q000601:surgery; D003911:Dextrans / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D017984:Enoxaparin / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging / Q000517:prevention & control*; D008297:Male; D010973:Platelet Adhesiveness / Q000187:drug effects; D011097:Polygeline / Q000008:administration & dosage / Q000494:pharmacology; D011138:Polytetrafluoroethylene; D011877:Radionuclide Imaging; D011897:Random Allocation; D012756:Sheep; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000517:prevention & control*; D014654:Vascular Patency / Q000187:drug effects
D003911:Dextrans; D017984:Enoxaparin; D012965:Sodium Chloride; D005340:Fibrinogen; D011138:Polytetrafluoroethylene; D011097:Polygeline