New England Center for Stroke Research; Department of Radiology
Cardiovascular Diseases | Computational Neuroscience | Disease Modeling | Nervous System Diseases | Neurology | Radiology
Many ischaemic stroke patients who have a mechanical removal of their clot (thrombectomy) do not get reperfusion of tissue despite the thrombus being removed. One hypothesis for this ‘no-reperfusion’ phenomenon is micro-emboli fragmenting off the large clot during thrombectomy and occluding smaller blood vessels downstream of the clot location. This is impossible to observe in-vivo and so we here develop an in-silico model based on in-vitro experiments to model the effect of micro-emboli on brain tissue. Through in-vitro experiments we obtain, under a variety of clot consistencies and thrombectomy techniques, micro-emboli distributions post-thrombectomy. Blood flow through the microcirculation is modelled for statistically accurate voxels of brain microvasculature including penetrating arterioles and capillary beds. A novel micro-emboli algorithm, informed by the experimental data, is used to simulate the impact of micro-emboli successively entering the penetrating arterioles and the capillary bed. Scaled-up blood flow parameters – permeability and coupling coefficients – are calculated under various conditions. We find that capillary beds are more susceptible to occlusions than the penetrating arterioles with a 4x greater drop in permeability per volume of vessel occluded. Individual microvascular geometries determine robustness to micro-emboli. Hard clot fragmentation leads to larger micro-emboli and larger drops in blood flow for a given number of micro-emboli. Thrombectomy technique has a large impact on clot fragmentation and hence occlusions in the microvasculature. As such, in-silico modelling of mechanical thrombectomy predicts that clot specific factors, interventional technique, and microvascular geometry strongly influence reperfusion of the brain. Micro-emboli are likely contributory to the phenomenon of no-reperfusion following successful removal of a major clot.
neuroscience, clot fragmentation, thrombectomy, ischaemic stroke
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DOI of Published Version
bioRxiv 2020.11.30.403808; doi: https://doi.org/10.1101/2020.11.30.403808. Link to preprint on bioRxiv.
Now published in PLOS Computational Biology doi: 10.1371/journal.pcbi.1008515
El-Bouri WK, MacGowan A, Józsa TI, Gounis MJ, Payne SJ. (2020). Modelling the impact of clot fragmentation on the microcirculation after thrombectomy [preprint]. University of Massachusetts Medical School Faculty Publications. https://doi.org/10.1101/2020.11.30.403808. Retrieved from https://escholarship.umassmed.edu/faculty_pubs/1837
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