Fig. 1.  A Thromboelastometry (ROTEM®; Pentapharm, Munich, Germany) tracings during bivalirudin anticoagulation. Native whole blood samples (300 μl) were triggered with 20 μl of the commercial tissue factor reagent EXTEM (Pentapham). FibTEM® assays were performed similarly with the addition of cytochalasin D to exclude platelet interactions with polymerized fibrin. It is notable that blood clotting (  i.e. , fibrin polymerization) occurs even after the bolus bivalirudin injection after a delay.  B Thromboelastometry (ROTEM®) tracings in pooled plasma spiked with argatroban or bivalirudin. Plasma samples (300 μl) were triggered with 20 μl of EXTEM reagent and CaCl². The onset of fibrin polymerization was more delayed with argatroban at 10 μg/ml than bivalirudin at 20 μg/ml due to lesser molar concentration of the latter (20 μm  vs. 10 μm). The maximal clot formation reaches the same level over time.