Anti-thrombotic efficacies of enoxaparin, dalteparin, and unfractionated heparin in venous thrombo-embolism.
BACKGROUND
Few data exist by which the anti-thrombotic efficacy of different anticoagulants may be compared. We used a radiolabeled antibody specific for polymerizing fibrin to compare the in vivo anti-thrombotic potencies of different systemic anticoagulants (enoxaparin, dalteparin, and unfractionated heparin).


RESULTS
Deep venous thrombi (DVTs) were induced in dogs' femoral veins. The dogs were then treated with one of the following subcutaneous regimens: enoxaparin 100 units/kg (1.0 mg/kg) every 12 hours (n=4), dalteparin 200 units/kg every 24 hours (n=4), or unfractionated heparin 240 units/kg every 8 hours with dose adjustment via aPTT (n=3). 111Indium-labeled anti-fibrin antibodies, specific for propagating thrombi, were given intravenously and nuclear scans of the legs were taken over the following 24 hours. Thrombus propagation was estimated by the ratio of gamma emissions from the legs containing DVTs divided by the emissions from the contralateral "control" legs. DVTs accumulated labeled anti-fibrin antibodies at the same rates in both the enoxaparin group and the dalteparin group (gamma emissions 171+/-6% and 168+/-36% of control by 24 hours, respectively). DVTs in the adjusted dose unfractionated heparin group tended to accumulate antibodies at a slower rate (129+/-19% of control by 24 hours).


CONCLUSIONS
Enoxaparin and dalteparin inhibited propagation of pre-formed thrombi to the same degree. Subcutaneous unfractionated heparin, adjusted every 8 hours by aPTT, tended to suppress ongoing thrombosis more than either LMWH.
Morris
T A
TA
Division of Pulmonary and Critical Care Medicine, University of California, San Diego, CA 92103-8372, USA. t1morris@ucsd.edu
Marsh
J J
JJ
Konopka
R
R
Pedersen
C A
CA
Chiles
P G
PG
D000818:Animals; D000906:Antibodies; D000925:Anticoagulants / Q000592:standards / Q000627:therapeutic use; D021721:Balloon Occlusion; D017985:Dalteparin / Q000592:standards / Q000627:therapeutic use; D003952:Diagnostic Imaging; D004195:Disease Models, Animal; D004285:Dogs; D004353:Drug Evaluation, Preclinical; D017984:Enoxaparin / Q000592:standards / Q000627:therapeutic use; D015951:Factor Xa / Q000378:metabolism; D065427:Factor Xa Inhibitors; D005269:Femur / Q000098:blood supply; D005337:Fibrin / Q000276:immunology; D005720:Gamma Rays; D006493:Heparin / Q000592:standards / Q000627:therapeutic use; D006495:Heparin, Low-Molecular-Weight / Q000592:standards / Q000627:therapeutic use*; D007205:Indium Radioisotopes; D011516:Prothrombin / Q000037:antagonists & inhibitors / Q000378:metabolism; D013923:Thromboembolism / Q000517:prevention & control; D020246:Venous Thrombosis / Q000276:immunology / Q000517:prevention & control
D000906:Antibodies; D000925:Anticoagulants; D017984:Enoxaparin; D065427:Factor Xa Inhibitors; D006495:Heparin, Low-Molecular-Weight; D007205:Indium Radioisotopes; D011516:Prothrombin; D005337:Fibrin; C025337:Factor IIa; D006493:Heparin; D015951:Factor Xa; D017985:Dalteparin