Hemostatic activation under anticoagulant treatment: A comparison of unfractionated heparin vs. nadroparin in the treatment of proximal deep vein thrombosis

Background: Multiple clinical trials have been performed to com pare standa rd heparin with low molecular weight heparin in the therapy of deep vein th rombosis, but little is known about the time course of the markers of hemos tatic system during the treatment with these two heparin regimens. Methods: Twenty patients with proximal deep vein thrombosis confirmed by du plex ultrasound and phlebography were randomly assigned to either unfractio nated heparin (UH) given as an intravenous bolus of 80 U/kg followed by a c onstant infusion of 18 U/kg/h, or nadroparin 185 AXa IU/kg once daily subcu taneously. Oral anticoagulants were started at day 4. Markers of hemostatic activation (F1 + 2, FPA, TAT, D-dimer) were measured daily for 4 days. Pri mary end-points were the time course of these markers; secondary endpoints consisted in the evaluation of thromboembolic and hemorrhagic complications by clinical outcome and Marder score. Results: Treatment with UH resulted in a rapid achievement of therapeutic h eparin levels. UH reduced markers of fibrin formation and fibrinolysis more rapidly than nadroparin (p < 0.05). Within the nadroparin group activation of prothrombotic markers four hours after the subcutanous injection (peak level) was significantly lower when compared with the time prior to injecti on (trough level). Secondary endpoints showed no significant difference bet ween the two groups. Conclusion: Continuous intravenous perfusion of UH administered on a basis of a weight-adjusted nomogram controlled markers of the hemostatic system m ore rapidly than once-daily subcutaneously administered weight-adjusted nad roparin.