OC 53.5 - Thrombin generation better than coagulation markers for predicting bleeding in patients supported with veno-venous extracorporeal membrane oxygenation.

Tuesday, June 25, 2024

10:30 – 10:45 ICT

Room: Ballroom B3

Presenting Author(s)

DA

Deepa J. Arachchillage, MD

Consultant haematologist, honorary senior lecturer & MRC CARP fellow
Department of immunity & inflammation, Centre for Haematology, Imperial College London, London. UK
London, England, United Kingdom

Co-Author(s)

JM

James E. Manning, MBChB MSc

Internal medicine trainee & honorary clinical research fellow
Department of Immunity & Inflammation, Centre for Haematology, Imperial College London. London. UK
London, England, United Kingdom
Magdalena Gierula

Post Doctoral Researcher
Department of Immunology and Inflammation, Imperial College London, London, United Kingdom
London, England, United Kingdom
MG

Mihaela Gaspar

Clinical nurse Specialist in Blood Transfusion
Royal Brompton Hospital, London, UK
London, England, United Kingdom
KF

Kamani Farah

Chief Biomedical scientist
Royal Brompton Hospital, London, UK
London, England, United Kingdom
SV

Saravanan Vinayagam

researcher
Department of Haematology, Imperial College Healthcare NHS Trust, London, UK
London, England, United Kingdom
Mike Laffan

Professor of haemostasis & thrombosis
Imperial College London, London. UK
London, England, United Kingdom
Josefin Ahnström

Senior Lecturer in Haematology
Imperial College London
London, England, United Kingdom

Background: Extracorporeal Membrane Oxygenation (ECMO) causes contact activation and increases thrombotic risk. Anticoagulation, usually unfractionated heparin maintains circuit patency and prevents thrombosis, increases haemorrhagic risk, requiring careful monitoring. Heparin anticoagulant effects are not fully captured by routine coagulation tests, making management challenging.

Aims: To assess haemostatic changes in patients supported with veno-venous (VV)-ECMO for respiratory failure due to viral pneumonia and their association with major bleeding (MB), thrombosis and mortality.

Methods: This ethically approved prospective observational study comprised fifty VV-ECMO patients anticoagulated with heparin (Aug 2018-Jan 2020). Coagulation factors levels and thrombin generation (TG) were measured in heparinase treated samples prior, during and post ECMO. CT brain was performed within 24hrs of VV-ECMO, and further imaging performed when indicated.

Results: Mean age was 43.7±13.1years, 54% were men and median ECMO duration was 9(3-41) days. ICH and ischaemic stroke occurred in 10% and 4%, respectively within 24hrs of initiating ECMO. The 180-day mortality was 10%; 34% developed thrombosis and 28% developed major bleeding (43% ICHs).
Coagulation factors fell significantly within first 24hrs on ECMO but returned to normal by day 5, and increased post de-cannulation (Table 1). TG in heparinase treated samples decreased significantly throughout ECMO, with nadir at decannulation. Total tissue factor pathway inhibitor (TFPI) and TFPIα rose throughout ECMO (Table 2), correlated with reduced and delayed TG. VWF:RCo/VWF:Ag was significantly reduced.
In multivariate analyses (corrected for EMCO duration), raised creatinine, pCO2, prothrombin time and thrombocytopenia at cannulation were associated with increased mortality. VWF:RCoF/VWF:Ag ratio < 0.6 and low TG in first 24hrs were associated with MB whilst raised fibrinogen and TG increased risk of thrombosis. MB increased mortality 3.6-fold whilst thrombosis had no impact.

Conclusion(s): PT, APTT, and coagulation factors were not associated with bleeding or thrombosis. TG may be a better predictor of thrombosis and MB as this assesses the effects of TFPIα.