Abstract Number: PB0749
Meeting: ISTH 2020 Congress
Background: Thrombosis and haemorrhage are common complications of extracorporeal membrane oxygenation (ECMO). Haemostatic changes that occur during ECMO and their contribution to these complications have been poorly studied, especially fibrinolysis.
Aims: To assess the changes in fibrinolytic factors over a 24-hour period in an ex vivo model of ECMO.
Methods: A simulated adult ex vivo circuit with a centrifugal pump was designed for 24-hours using whole blood (donors had hereditary haemochromatosis) diluted with 3.2% sodium citrate and PlasmaLyte 148 solution. Six circuits were analysed. Samples were taken with time-matched controls at 6 time points (0, 1, 4, 8, 12 and 24 hours). Clauss fibrinogen levels and ELISA were performed for D-dimer, plasminogen activator inhibitor (PAI)-1, tissue plasminogen activator (t-PA) antigen, prothrombin fragments (PF) 1+2, thrombin-activated fibrinolysis inhibitor (TAFI) antigen and plasmin-antiplasmin (PAP) complexes. Statistical analysis was measured by Mann-Whitney U test. Haemostatic results were expressed as % of the value at initiation of the experiment.
Results: Haemodilution occurred with a haematocrit fall from a median 0.40 (range 0.37 – 0.54) to 0.19 (0.18-0.22) after addition of PlasmaLyte, but there were no further significant changes. There were no changes over time in D-dimers, PF1+2 and fibrinogen. tPA levels decreased over 24-hours with a larger decrease in samples from the circuit than control (56% vs 12%, p=0.025). PAP complexes, TAFI antigen and PAI-1 levels increased over time (91%, 20% and 48% increases from baseline respectively, non-significant). There was an increase in PAP complexes and PAI-1 levels (91% vs 32% and 48% vs 27% at 24-hours) from the circuit compared to controls although similar TAFI levels (20% vs 18% at 24-hours).
Conclusions: This ex vivo simulated circuit showed an elevation in PAP complexes during ECMO. PAI-1 increased and tPA decreased over 24-hours. Further analysis is required in patients during ECMO and correlated with haemostatic phenotype.
|Fibrinolytic Factor||Fibrinogen||D-dimer||PF1+2||PAP Complex||tPA Antigen||PAI-1||TAFI|
|Circuit after 24 hours||-5.5%||+4.1%||+9.8%||+90.7%||-56.2%||+48.2%||+19.7|
|Control after 24 hours||+2.6%||+0.5%||-5.7%||+31.6%||-12.4%||+26.6%||+17.6%|
[Mean % changes in fibrinolytic factors at 24 hours compared to initiation of ex vivo circuit]
To cite this abstract in AMA style:Doyle A, Gooby N, Parmar K, Breen KA, Barrett NA, Retter A, Hunt BJ. Changes in Fibrinolytic Factors in a Simulated Extracorporeal Membrane Oxygenator Circuit [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/changes-in-fibrinolytic-factors-in-a-simulated-extracorporeal-membrane-oxygenator-circuit/. Accessed January 28, 2022.
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