ABSTRACT
Hemodialysis was performed on dogs, following intravenous bolus injections of LHG at dosage levels of 50, 100 and 200 IU/kg and heparin at the levels of 100 and 200 IU/kg. LHG exerted dose-dependent anticoagulant effects and prolonged the hemodialysis time, compared to heparin with similar anti-Xa activity. When LHG was administered, the half-life of plasma anti-Xa activity was longer than that of heparin at similar anti-Xa activity. LHG prolonged the activated partial thromboplastin time (APTT) linearly and dose-dependently. However, the prolongation was much less than that of heparin, and the anticoagulant activity of LHG continued even after the APTT returned to the value before LHG administration. When LHG was administered, whole blood Xa activated coagulation time (XCT) and plasma Xa activated coagulation time (PXCT) were prolonged in a significantly greater degree compared to APTT. Therefore, XCT and PXCT were considered to be appropriate parameters for monitoring LHG. In the groups administered with LHG at 100 and 200 IU/kg, where hemodialysis could be continued for 8 hr, the tissue factor pathway inhibitor (TFPI) activity in the plasma tended to show a sustained increase. These findings suggested the possibility that not only the antithrombin III dependency mechanism but also the TFPI mechanism contributed to a longer LHG hemodialysis duration compared to heparin administration.
