A randomised study using 40 New Zealand White male rabbits was performed to compare the effects of three antithrombotic drugs on eight clinical haemostatic function tests. The animals were divided into four treatment groups. The treatment groups were saline (control), unfractioned heparin (UFH), low-molecular-weight heparin (LMWH), and recombinant hirudin (r-hirudin). Blood samples were collected 2 and 12 h after administration of the drugs. The following tests were performed: bleeding time (BT), platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen concentration (Fg), antithrombin III (ATIII), and antifactor Xa activity (antiXa activity). Effects attributable to drug treatment for each analyte were determined by comparison with the control group. At 2 h after medication, in the UFH treated group, TT was moderately prolonged (p<0.05) and antiXa activity was significantly higher (p<0.05) than the respective values of the control group. In the LMWH-treated group the antiXa activity was significantly higher (p<0.01) than that of the control group. In the r-hirudin-treated group, the APTT and TT were significantly prolonged (APTT, p<0.01; the TT samples did not clot) when compared to the control group. However, 12 h after administration, no significant differences (p>0.05) between groups were observed for any of the studied analytes. It might be concluded that the antiXa assay has the potential of being a sensitive screen for heparin therapy and that the absence of changes in the bleeding time, antithrombin III, and antiXa assays - with a markedly prolonged thrombin time - indicates that, in vivo, r-hirudin acts as a specific inhibitor of thrombin. © 1997 Springer-Verlag London Limited.
|Journal||Comparative Clinical Pathology|
|Publication status||Published - 1 Dec 1997|
- Anthithrombin III
- Low-molecular-weight heparin
- Recombinant hirudin
- Unfractioned heparin