Modelling the impact of clot fragmentation on the microcirculation after thrombectomy
Journal
PLoS Computational Biology
Journal Volume
17
Journal Issue
3
Date Issued
2021
Author(s)
Abstract
Many ischaemic stroke patients who have a mechanical removal oftheir clot (thrombectomy) do not get reperfusion of tissue despitethe 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. Copyright: ? 2021 El-Bouri et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Subjects
algorithm
arteriole
Article
blood clot
blood flow
brain blood vessel
brain microvasculature
capillary
clot fragmentation
controlled study
geometry
human
human tissue
in vitro study
intervention study
limit of quantitation
mechanical thrombectomy
microcirculation
reperfusion
scale up
simulation
brain ischemia
pathology
thrombectomy
thrombosis
treatment outcome
Brain Ischemia
Humans
Microcirculation
Thrombectomy
Thrombosis
Treatment Outcome
Type
journal article