UC Riverside

Flow diverting stents have transformed the treatment for intracranial aneurysms. These tightly braided metallic wire cylinders when deployed endovascularly at the neck of an aneurysm have been shown to drastically reduce intra-aneurysmal hemodynamic velocity and aneurysm lumen wall shear stress. These devices reduce the chance of rupture and thereby hemorrhagic stroke while simultaneously inducing thrombogenic cues for eventual aneurysm absorption. Current clinically available devices achieve this change in IA by manipulating device porosity and pore density to reduce shear into the aneurysm. Herein, it is demonstrated that device porosity, pore density and shear are not the only design parameters and physical mechanism to consider for flow diversion. 2D and 3D numerical simulations are compared to experimental devices deployed across the neurovasculature with varying diverter strut aspect ratios. Device designs whose struts have an aspect ratio greater than 1 are shown to be effective at inducing hemodynamic transition into aneurysmal flow regimes associated with good clinical outcomes. High aspect ratio devices allow for higher porosities and reduce the IA hemodynamic response to potential changes in porosity. While addressing numerous clinical complications such as in-stent stenosis and edema this design simultaneously widens the range of devices indicated for use in high risk areas such as the posterior communicating artery and basilar trunk by altering the balance of energy transfer through the device from parent anatomy to aneurysm. These results show the potential of more robust devices of higher porosity and a reimagining of the physical forces being manipulated when flow diversion is considered in the clinic.