Investigation of the Pressure and Flow Dynamics during Aspiration Thrombectomy: A Mathematical Modelling Study

Aspiration thrombectomy is a life-saving interventional procedure to remove a blood clot from the brain of stroke patients. The pressure and blood flow dynamics during this procedure are crucial in determining the clinical outcomes. A mathematical model based on Hagen-Poiseuille law of fluid flow in a tube is adapted to simulate the pressure and fluid flow characteristics in an in vitro model of an occluded and unoccluded cerebrovascular network that mimics a poor (unilateral) and good (symmetrical) collateral flow within the Circle of Willis. The results show that in the absence of an occlusion, the pressure and pressure drop are higher in the symmetrical network compared to that in the unilateral network. This is due to the additional limb in the symmetrical network that must be supplied, which is absent in the unilateral network. In the presence of an occlusion, the flow reduces in the obstructed vessel, the collateral flow, overall pressure and pressure drop increases in both systems, but is higher for the symmetrical network. The results compare qualitatively with those observed in in vitro studies and with clinical observations. The theoretical framework lays the foundation for more advanced models for the pressure and blood flow dynamics towards clinical applicability.