Summary
The direct thrombin inhibitor argatroban offers some significant advantages over unfractionated
heparin (UFH) and is recommended as an alternative anticoagulant during percutaneous
coronary interventions (PCI). The impact of argatroban on cardiac catheter thrombosis
– a severe potential complication of PCI – has not been systematically studied yet.
The aim of the present study was to test in vitro the hypothesis that argatroban is equivalent to the more established anticoagulants
UFH and enoxaparin in preventing catheter thrombus formation. Blood pretreated with
the anticoagulants of interest was continuously circulated through a guiding catheter
by using a roller pump for a maximum experimental period of 60 minutes. In an alternate
model, coagulation was mechanically induced by a magnetic stirrer. Coagulation parameters,
overall thrombus weight and electron microscopic features (deposits of platelets and
fibrin on the catheter surface) were quantified as endpoints. Argatroban (administered
as bolus or continuous in-fusion), UFH (bolus), and enoxaparin (bolus) significantly
reduced catheter thrombus formation compared to untreated controls. Here, neither
overall thrombus weight nor platelet/fibrin deposition was different among the specific
anticoagulants. Declining ACT (activated clotting time) levels – which were found
in the argatroban bolus group – could be prevented by continuous infusion. In magnetic
stirrer-induced coagulation, thrombus weight was lower following bolus treatment with
UFH and enoxaparin compared to argatroban. These data suggest that the potential for
argatroban in preventing catheter thrombosis is comparable to that of UFH and enoxaparin.
However, the anticoagula-tory efficacy varied, depending on the model of coagulation
activation, which demonstrates the necessity for specific testing.
Keywords
Anticoagulation - direct thrombin inhibitors - PCI