Compacting a Single Flow Diverter versus Overlapping Flow Diverters for Intracranial Aneurysms: A Computational Study

Abstract

Background and Purpose Locally compacting the mesh of a flow diverter by a dynamic push-pull technique can accelerate intracranial aneurysm healing. We asked how this deployment strategy compares to overlapping two flow diverters in terms of aneurysmal flow reduction. Materials and Methods Using a high-fidelity virtual stenting method, we simulated three flow diverter strategies (single non-compacted, two overlapped, and single compacted) in three aneurysms (a fusiform, a large saccular, and a medium saccular). Computational fluid dynamics analysis provided post-treatment hemodynamic parameters including time-averaged inflow rate, aneurysm-averaged velocity, wall shear stress, total absolute circulation, and turnover time. We examined the relationship between the achieved degree of compaction and aneurysm orifice area. Results Flow diverter compaction resulted in a compaction coverage of 57%, 47%, and 22% over the orifice of the fusiform, large, and medium saccular aneurysm, respectively. Compaction coverage increased linearly with orifice area. In the fusiform aneurysm, the single compacted flow diverter accomplished more aneurysmal flow reduction than the other two strategies, as indicated by all five hemodynamic parameters. In the two saccular aneurysms, the overlapped flow diverters achieved the most flow reduction, followed by the single compacted and the non-compacted flow diverter. Conclusion Compacting a single flow diverter can outperform overlapping two flow diverters in aneurysmal flow reduction, provided that compaction produces a mesh denser than two overlapped flow diverters, and this denser mesh covers a sufficient portion of the aneurysm orifice area, to which we suggest a minimum of 50%. This strategy is most effective for aneurysms with large orifices, especially fusiform aneurysms.

Interaction between Flow Diverter and Parent Artery of Intracranial Aneurysm: A Computational Study

“…This will inevitably lead to different vascular injury of the parent artery. Damiano et al point out that compacting a single flow diverter could be a superior strategy to overlapping multiple flow diverters, from both a biologic and economic standpoint [ 17 ]. Overlapping multiple metal devices increases the risk for in-stent thrombosis and stenosis [ 17 , 20 ].…”

“…Damiano et al point out that compacting a single flow diverter could be a superior strategy to overlapping multiple flow diverters, from both a biologic and economic standpoint [ 17 ]. Overlapping multiple metal devices increases the risk for in-stent thrombosis and stenosis [ 17 , 20 ]. However, from the results of this study, compacting a single flow diverter will lead to greater contact pressure of the parent artery at the aneurismal orifice.…”

“…One deployment strategy is noncompacting with HiFiVS and the other is compacting with HiFiVS. In the previous studies of virtual deployment braided stent using HiFiVS method [ 11 , 12 , 17 ], the vessel wall is treated as rigid. For comparison, FEM calculation wherein vessel wall is assumed as rigid in this study is also carried out to investigate the interaction between the braided stent of the flow diverter and the intracranial aneurysm.…”

Ostium Ratio and Neck Ratio Could Predict the Outcome of Sidewall Intracranial Aneurysms Treated with Flow Diverters

“…MCR quantifies the percentage area of the aneurysm neck covered by the FD wire-struts, and pore-density quantifies the number of FD pores per unit area at the neck plane. 18–20 MCR and pore-density could not be measured accurately from post-treatment images due to imaging artifacts after FD implantation. Therefore, virtual FD deployment was performed on each case to simulate clinical FD deployment and quantify MCR and pore-density.…”

A novel virtual flow diverter implantation method with realistic deployment mechanics and validated force response

“…Among others, procedural factors impacting the deployment may play an important role as causes of such complications 14‐16 . The material properties, diameter, length of the chosen FD, and the deployment technique may all influence the wall apposition of the device, the porosity across the neck, and the force exerted on the vessel wall by the device 17‐21 . Subsequently, the device should be carefully chosen, to best match the individual anatomy of the vessel section involved.…”