An In Vitro Study of Embolus Migration in an Anatomical Cerebrovascular Model

Acute ischemic stroke (AIS) remains a driver of mortality and long-term impairment, with clinical outcomes depending strongly on the final lodging site of emboli within the cerebrovasculature. However, the physical mechanisms governing embolus migration and partitioning remain incompletely understood. Further, due to the paucity of experimental data in realistic anatomical models under pulsatile flow conditions, computational modeling of embolus migration in AIS remains largely unvalidated. The study objective is to acquire experimental benchmark data of embolus migration in an in vitro anatomical model comprising the aorta and the cerebrovasculature. Experiments are performed under pulsatile flow to quantify the migration of 480 rigid nylon spheres (1.58-4.76 mm) and 160 deformable blood emboli (2.53-3.95 mm). Emboli are injected into both Newtonian and non-Newtonian blood analogs to evaluate the influence of size, deformability, and fluid rheology. Results demonstrate an inverse relationship between embolus size and the propensity to migrate into the cerebrovasculature. Furthermore, when comparing emboli of similar dimensions, deformable blood clots exhibited consistently higher migration rates to the supra-aortic branches. While rheology slightly influences the migration of rigid spheres, it has a negligible effect on the partitioning of blood emboli. These findings suggest that embolus deformability plays a more dominant role than rheology in dictating whether realistic blood emboli migrate to the cerebral circulation. Consequently, to predict embolus trajectories and lodging sites in AIS, future in silico studies should incorporate fluid-structure interaction modeling to account for realistic clot deformability.