PB1184 - Monitoring of Low Molecular Weight Heparin by thrombodynamics analyser system (TD T2 T) in Intensive Care Patients with COVID-19 Infection

Tuesday, June 27, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

AR

Anne Riddell

Laboratory Head of Department (Special Coagulation, Haemophilia) and HSL Scientific Lead Coagulation
Katharine Dormandy Haemophilia and Thrombosis Centre, Royal Free Hospital, London, UK
London, England, United Kingdom

Co-Author(s)

PP

Panagiotis Panagiotidis

Biomedical Scientist
Katharine Dormandy Haemophilia and Thrombosis Centre, Royal Free Hospital, London, UK
London, England, United Kingdom
AD

Anja Drebes

Consultant Haematologist
Katharine Dormandy Haemophilia and Thrombosis Centre, Royal Free Hospital, London, UK
London, England, United Kingdom
Paul Batty, MBBS, PhD (he/him/his)

Associate Professor
University College London
London, United Kingdom
PC

Pratima Chowdary, MD

Consultant Haematologist
Katharine Dormandy Haemophilia and Thrombosis Centre, Royal Free London NHS Foundation Trust, London, United Kingdom
London, England, United Kingdom
GG

Giulia Getti

Associate Professor in Microbiology
University Of Greenwich
London, England, United Kingdom

Background: SARS-Cov-2 (COVID-19) pneumonia is associated with a prothrombotic state in critically ill patients. Low molecular weight heparin (LMWH) is used for treatment and prevention of thrombosis. A recent study described a novel global assay for monitoring the prothrombotic haemostatic state of SARS-Cov-2 (COVID-19) pneumonia.

Aims: To evaluate fibrin clot formation in critically ill patients during the COVID-19 pandemic on prophylactic or treatment dose LMWH.

Methods: Citrated plasma samples (February– June 2021) were allocated to groups based on diagnosis (A:COVID-19; B:non-COVID-19) and anti-Xa (1: < 0.3 IU/mL, 2: 0.3-0. 5 IU/mL, 3: 0.5-0.7 IU/mL & 4: >0.7 IU/mL). Samples were analysed using the thrombodynamics T2-T system with TD(X) test. 120µL plasma added to a cuvette containing activating inserts coated with immobilised tissue factor. Reagent I (intrinsic pathway inhibitor) and CaCl2 were added. Clot development (clot-size over time) was evaluated.

Results: Residual plasma samples from 60 patients admitted to ICU with (n=40) or without COVID-19 (n=20) and healthy controls(n=10) were included. Clot size (CS) was moderately sensitive to increasing LMWH concentration (anti Xa) (r-0.4489, P=0.0011) (Figure 1). Spontaneous clot formation (Tsp) was absent in all samples, (supported by Vst and V being equal). Compared to healthy controls, all patient samples demonstrated increased clot lag time (TLag) and decreased clot density (D), clot growth (V), initial rate of clot growth (Vi), and stationary rate of clot growth (Vst). Differences between in Tlag, CS, Vi and D were seen in patients with COVID19 with anti-Xa 0.3-0.7 (Groups 2 – 3) compared to those who did not have COVID19 with similar Anti-Xa levels (Table 1).

Conclusion(s): TD parameters (Tlag, V, Vi, Vst and CS) were sensitive to LMWH in plasma samples and there is a suggestion that non COVID-19 samples were more resistant (Vi, CS and D) to the action of LMWH. Further investigation is required.