Abstract
Flow diverting stents are deployed to reduce the blood flow into the aneurysm, which would thereby induce thrombosis in the aneurysm sac; the stents prevent its rupture. The present study aimed to examine and quantify the impacts of different flow stents on idealized configurations of the cerebral artery. In our study, we considered a spherical sidewall aneurysm located on curved and tortuous idealized artery vessels and three stents with different porosities (70, 80 and 90%) for deployment. Using computational fluid dynamics, the local hemodynamics in the presence and absence of the stents were simulated, respectively, under the assumption that the blood flow was unsteady and non-Newtonian. The hemodynamic parameters, such as the intra-aneurysmal flow, velocity field and wall shear stress and its related indices, were examined and compared among the 12 cases simulated. The results illustrated that with the stent deployment, the intra-aneurysmal flow and the wall shear stress and its related indices were considerably modified depending on both stent and aneurysm/artery geometries, and that the intra-aneurysmal relative residence time increased rapidly with decreasing stent porosity in all the vessel configurations. These results also inform the rationale for selecting stents for treating aneurysms of different configurations.
Highlights
The cerebral aneurysm is a potentially deadly degenerative vascular disease that can initially be asymptomatic
This threshold can be assessed by computational simulations that evaluate the reduction of flow and the hemodynamical indices that could help to predict the recirculation of blood flow within the aneurysmatic sac and the risk of rupture [46]
Our results show that the examined stents all accomplish the desired reduction of flow rate into the aneurysm, including the recently designed stent that features the highest porosity
Summary
The cerebral aneurysm is a potentially deadly degenerative vascular disease that can initially be asymptomatic. The physical processes that cause its formation are still being investigated, but many studies in this field have highlighted the importance of the local hemodynamics on the development of the aneurysm once it is present in a cerebral vessel [1,2,3,4]. Due to local blood recirculation, the aneurysmatic sac may rupture, leading to high rates of morbidity and mortality [5]. It is estimated that 8% of all strokes are caused by ruptured aneurysms [6].
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