THE ANTITHROMBOTIC POTENTIAL OF DALTEPARIN IN MAN ASSESSED INDIRECTLYBY WESSLERS TECHNIQUE

The aim of this study was to demonstrate the effectiveness of a new ex perimental approach for assessing the antithrombotic potential of low molecular weight heparins (LMWH) such as dalteparin. In this approach, sera obtained from healthy volunteers treated with various i.v. doses of dalteparin (30, 60 or 120 anti-Xa IU/kg) or placebo (physiological saline) were used as the thrombogenic challenge in a Wessler's stasis model of experimental venous thrombosis in the rat. Sera from placebo -treated volunteers showed a stable thrombogenic activity (0.25 ml/kg of serum producing thrombi of about 50 mg wet weight). Sera from healt hy volunteers having previously received dalteparin however demonstrat ed dose- and time-related reductions in their thrombogenic activity. H alf-lives of these effects were 300, 444 and >480 min for 30, 60 and 1 20 anti-Xa IU/kg dalteparin respectively. These values were significan tly higher than the corresponding anti-Xa and anti-IIa half-lives.