Abstract 3205: In Vitro Comparison Of Fondaparinux, Unfractionated Heparin, And Enoxaparin In Prevention Of Heart Catheter Thrombus
Introduction Fondaparinux (Fonda) is a selective inhibitor of coagulation factor Xa. The aim of this study was to investigate, whether treatment with Fonda in comparison to UFH and Enoxa is associated with development of catheter thrombus in an in vitro model.
Materials and Methods Blood (each 50ml) from 10 healthy male blood donors was used. The blood was filled directly from the blood donors veins into a 50ml tube prepared with an anticoagulant [group 1 UFH 0.8U/ml, group 2 UFH + Integrilin 1.7μg/ml, group 3 Enoxa 0.6U/ml, group 4 Enoxa + Integrilin, group 5 Fonda 0.5μg/ml, group 6 Fonda + Integrilin, group 7 Fonda + UFH (0.5U/ml), and group 8, Fonda + Integrilin + UFH]. After filling the anticoagulated blood in the tube (preserved in a 37°C water bath) blood circuited from the tube to a masterflex roller pump and back into the tube via a guiding catheter. Heart catheters were exposed to blood at a slow flow rate (3ml/min), which was produced by a masterflex-roller-pump for duration of 60 min. To quantify the thrombi that developed, each heart catheter was weighed before and after the experiments. Furthermore, number of erythrocytes and fibrinogen depletion were calculated on the inner surface of the heart catheter tips after electron microscopy analyses.
Results In the experiments with solely anticoagulation by Fonda (0.5μg/ml) catheter clotted after a maximum of approximately 45 minutes, also by using increasing concentrations (up to 2μg/ml) in the last experiments. Same results were found in the experiments using Fonda in combination with Integrilin. In all other experiments, including the combination of 0.5μg/ml Fonda with 0.5U/ml UFH, experiments could be finished. Furthermore, thrombus weight and cell/fibrinogen count on the inner surface of the heart catheter tips were significantly increased in group 5 (Fonda) and group 6 (Fonda + Integrilin) in comparison to all other treatment groups.
Summary Treatment with Fonda, also in combination with Integrilin, was not sufficient for the prevention of heart catheter thrombus in our in vitro study. However, experiments using the combination of Fonda with half therapeutic dosages of UFH (0.5U/ml) were as efficient as other treatment strategies for prevention of catheter thrombus.