PB0131 - ECATEM – a New Approach to Monitor Intravenous Direct Thrombin Inhibitors

Background: Intravenous direct thrombin inhibitors (IV DTIs) are emerging as safe alternatives to unfractionated heparin (UFH) in extracorporeal membrane oxygenation (ECMO) due to more predictable pharmaceutical effect and avoidance of heparin-induced thrombocytopenia (HIT). In these clinical settings, IV DTI monitoring becomes crucial as a delicate balance in the antithrombotic regimen must be maintained to prevent thrombotic events within the ECMO circuit and bleeding episodes in the patients. ROTEM systems are available in point-of-care settings to provide rapid insights into patients’ coagulation status.

Aims: This study aimed to assess the performance of the proposed ROTEM ECATEM assay for monitoring direct thrombin inhibitors argatroban and bivalirudin.

Methods: ECATEM reagent consists of ecarin (from Echis Carinatus), calcium chloride, and a heparin inhibitor (polybrene). Normal whole blood was spiked with different argatroban and bivalirudin concentrations (0 to 5 µg/mL and 0 to 20 µg/mL, respectively), and the coagulation profile was measured on ROTEM delta or ROTEM sigma devices (Werfen, Germany). Reagents were reconstituted by pipetting 300 µL argatroban- or bivalirudin-containing donor blood to the lyophilized reagent. ECATEM clotting time (CT) was recorded.

Results: ECATEM CT reference range from 60 normal donors was 70.2 to 99.8 sec. ECATEM turnaround times for argatroban (0 - 5 µg/mL) and bivalirudin (0 - 20 µg/mL) were less than 20 and 15 mins, respectively. There was an excellent correlation for both argatroban (R2 = 0.9887, Figure 1) and bivalirudin (R2 = 0.9925, Figure 2).

Conclusion(s): The ECATEM assay provides quick (within 20 minutes) results and shows an excellent correlation to argatroban and bivalirudin concentrations up to 5 and 20 µg/mL, respectively. ECATEM may be a valuable tool to monitor IV DTIs.