Abstract Number: PB0299
Meeting: ISTH 2020 Congress
Background: Extracorporeal Membrane Oxygenation (ECMO) is a form of circulatory support for children with severe respiratory or cardiac failure. Circuit thrombosis increases mortality of children on ECMO. However, protein and cellular adsorption to the surface of the ECMO circuit, as an initiating factor for circuit thrombosis, has largely been overlooked.
Aims: To characterise the microstructure of the blood clot and blood components adsorbed onto an ECMO circuit obtained from a paediatric patient.
Methods: This study was approved by the Royal Children’s Hospital ethics committee. An ECMO circuit was collected from a one-year-old boy after he was successfully decannulated. A thrombus found post-oxygenator, as well as circuit samples from three different sites (Fig. 1) were studied using the Phenom XL desktop scanning electron microscope (SEM) (ATA Scientific, Australia).
Results: SEM images of the thrombus and circuit sites are shown in figure 2. The clot largely consists of erythrocytes trapped by fibrin (Fig. 2a). Circuit binding was markedly different between the three sites. Cells at site 1 show minimal aggregation (Fig. 2b), while site 2 contains a thin fibrin network and deposition surrounding leukocytes which is hypothesised to be the protein adsorption layer (Arrow c1). Site 3 shows significant binding to the circuit consisting of activated platelets, leukocytes, and red blood cells embedded in a thick fibrin network.
Conclusions: This is the first demonstration of ECMO circuit binding and site-specific differences in a circuit obtained from a paediatric patient. This is the first step towards characterising the blood components involved in circuit adsorption, showing the topography of the circuit binding. By identifying proteins/cells involved in circuit adsorption we will establish strategies to prevent this adsorption from taking place.
Acknowledgements: The authors would like to acknowledge the SEM imaging contributions of Peter Davis, Theano Stafidas and David Myint from ATA Scientific (Australia).
To cite this abstract in AMA style:Cai T, McCafferty C, Van Den Helm S, Bottrell S, Schultz B, Horton S, Barton R, Letunica N, Maclaren G, Chiletti R, Johansen A, Best D, Linden M, Newall F, d'Udekem Y, Butt W, Monagle P, Ignjatovic V. Microstructural Characterisation of in vivo Paediatric ECMO Circuit Binding and Blood Clot Structure [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/microstructural-characterisation-of-in-vivo-paediatric-ecmo-circuit-binding-and-blood-clot-structure/. Accessed May 16, 2022.
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