(432) Correlation of Thromboelastography & Standard Tests of Coagulation in Pediatric ECMO & VAD Patients

Introduction: Extracorporeal circulatory support devices commonly used in the Pediatric ICUs include Extracorporeal membrane oxygenation (ECMO) and Ventricular assist device (VAD) which require systemic anticoagulation to prevent life threatening events from clotting. However, there are significant number of hemorrhagic events (12-70%) that occur, many leading to mortality. Standard tests of coagulation like aPTT, anti Xa provide static information about a single aspect of the coagulation. Thromboelastography (TEG) provides a global picture of entire hemostasis. We hypothesize that TEG based anticoagulation titration is a feasible alternative and would be more predictive of bleeding complications than the standard tests.

Methods: This single-center retrospective cohort study included children ( < 18 years) who were on ECMO or VAD either on Heparin or Bivalirudin between January 2015 and December 2022 with TEG and standard tests of coagulation within 4 hours. The associations between the TEGs and standard tests with bleeding episodes (per ELSO) of the same calendar day were assessed.

Results: Twenty-one patients (52.4% female) with 288 repeated measures in TEGs and standard tests were included. Of all, 15 were on ECMO (median age 0 year, interquartile range [IQR] 0-2 years) and 8 were on VAD (median age 2.5 years, IQR 0.5-4 years). Nine patients died. R time had positive correlation with APTT (ρ=0.56) in VAD patients. In ECMO patients, R time (ρ=0.90) and alpha angle (ρ=-0.90) had a strong correlation with Anti Xa. The TEG parameters (alpha angle ρ=0.62, MA ρ=0.62, and Lysis 30 ρ=0.58) had a moderate correlation with platelets. (All p < 0.05). 22 bleeding episodes were seen in the whole cohort, with lower level of alpha angle (40.3 vs 64.5), MA (52.2 vs 61.9), and Lysis 30 (0 vs 0.4) compared to those collected in non-bleeding days (p < 0.001). APTT and Anti Xa were not significantly different by the bleeding status.

Conclusions: TEG correlates with the standard tests of coagulation while showing significant associations with bleeding episodes. We find that this correlation holds true for Bivalirudin which is now being used more for providing systemic anticoagulation for ECMOs and VADs. TEGs provide an additional benefit of allowing more targeted therapy with potential benefits to patient management.