Abstract Number: OC 40.4
Meeting: ISTH 2021 Congress
Background: Bivalirudin, an injectable direct thrombin (factor IIa) inhibitor, and unfractionated heparin (UFH) are both frequently used for anticoagulation therapy in the pediatric critical care setting. A functional test for the quantification and detection of resistance to these anticoagulants is not currently available.
Aims: Evaluate the ability of a point-of-care (POC) microliter volume coagulation test to detect the effect of bivalirudin and UFH and quantify the level of anticoagulation using a functional, clot time end point in pediatric critical care patients.
Methods: Under IRB approval, a retrospective analysis of 41 citrated, frozen, bio-banked plasma specimens from 15 anticoagulated pediatric patients was performed. Thirteen patients were on extracorporeal membrane oxygenation, one patient had a submassive pulmonary embolus and one patient was on a left ventricular assist device, providing 21 bivalirudin and 20 UFH samples. Each sample was tested and a Clotting Time Score (CTS) was derived. Reference CTS curves for each drug were made using spiked healthy adult samples. CTS results were compared to clinician-ordered coagulation tests.
Results: Using the CTS, the patients that had developed a pathological clotting event were detected with 100% sensitivity/ 72% specificity, as compared to 25% sensitivity/76% specificity and 0% sensitivity/0% specificity (per the reference ranges) for prothrombin time and activated partial thromboplastin time, respectively (Fig 1A). The CTS was able to detect sub-therapeutic anticoagulation levels in patients that were determined to be clinically-resistant and required to switch from UFH to bivalirudin (Fig 1B).
Conclusions: The CTS appears to be a good indicator of the level of anticoagulation for both UFH and bivalirudin and may be predictive of pathological clot formation, potentially due to anticoagulation resistance. The small sample volume required allows for more frequent testing without causing iatrogenic anemia, reducing the risk of anticoagulation-related complications and enabling the rapid identification of patients at high-risk for pathologic thrombotic events.
To cite this abstract in AMA style:Frydman GH, Berger BM, Kostousov V, Bruzdoski K, Papageorgiou D, Gokhale A, Navaei AH, Hensch LA, Hui SR, Teruya J. Novel, Point-of-Care Coagulation Test Detects Anticoagulation Resistance Predictive of Thrombotic Events in Pediatric ECMO Patients [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/novel-point-of-care-coagulation-test-detects-anticoagulation-resistance-predictive-of-thrombotic-events-in-pediatric-ecmo-patients/. Accessed December 5, 2021.
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