287: Hold on to That Txa: Clot Retraction Mimicking Fibrinolysis on Thromboelastography

Introduction: Assays such as thromboelastography (TEG) have been shown to decrease transfusion requirements and optimize outcomes, and are widely used in critical care management of bleeding and coagulopathy. The Lysis Index at 30 minutes (LY30) is a commonly-used TEG parameter generally considered to reflect fibrinolysis; in actively bleeding patients, LY30 elevation is treated with antifibrinolytic agents. However, activated platelet contractile forces can also reduce clot amplitude through a phenomenon known as “clot retraction”; this is unrelated to fibrinolysis and thought to reflect a hypercoagulable state. We present a case series of three critically ill patients with elevated LY30 parameters who appear to have clot retraction as opposed to fibrinolysis. Methods: Retrospective review of 3 surgical critical care patients with elevated LY30 parameter on TEG 6S global hemostasis with lysis assay, including visual review of tracing. Patients were male, ages 35-45; 2 had significant co-morbidities including end-stage liver disease each had normal TEG values on admission. Results: On visual inspection of elevated LY30 TEG tracings, each assay demonstrated a smooth, normal-appearing citrated rapid TEG curve; however, citrated kaolin tracings showed discrete sharp drops in amplitude concerning for clot retraction, as opposed to smooth, continuous amplitude reduction consistent with fibrinolysis. At the time of elevated LY30, one of these patients had a hypercoagulable maximal amplitude; other TEG parameters were normal. None of these patients had active bleeding at the time of the TEG assay in question. One patient received tranexamic acid (TXA) because of this assay result. Two patients had thrombotic complications; one patient had multiple non-occlusive extremity deep vein thromboses, and one patient had venous anastomotic thrombosis. Conclusions: Visual review of TEG assay results suggest these three patients had findings of clot retraction – a hypercoagulable state in which antifibrinolytic administration would be inappropriate and potentially harmful. As there are no rigorous diagnostic criteria to differentiate these two interpretations, visual review of isolated elevated LY30 results may be needed to prevent inappropriate antifibrinolytic therapy in critically ill patients.