Hemodynamic Alterations for Various Stent Configurations in Idealized Wide-neck Basilar Tip Aneurysm

Abstract

Stent-assisted coiling technology is widely used in the treatment of intracranial aneurysms. However, differences among various stent configurations have not been fully characterized. This study investigates the hemodynamic effects for various stent configurations. Computational fluid dynamics simulations were performed on an idealized wide-neck basilar tip aneurysm model, which was constructed from digital subtraction angiography images with a virtual stenting technique. The orifice of the aneurysm was tilted toward the left posterior cerebral artery (PCA). The right half-Y configuration caused only a small change in the overall intra-aneurysmal flow pattern compared with the pattern produced without a stent. Percentage of hemodynamic changes were all compared to the untreated aneurysm.The values of wall shear stress (WSS) and flow velocity showed reductions of 16.36 and 3.22 %, respectively. Although the Y configuration showed relatively obvious decreases of 56.27 and 33.55 % in WSS and flow velocity, respetively, the left half-Y configuration, which is usually deployed as the first stent clinically, produced a more obvious flow reduction than those of the right half-Y and Y configurations. Consistent decreases in the velocity and WSS were observed. WSS and flow velocity showed reductions of 58.39 and 41.76 %, respectively. The cross-bar configuration showed the highest WSS and flow velocity reductions (58.42 and 46.49 %, respectively). The right half-Y configuration had relative more impacts on the WSS of the right PCoA than the left half-Y configuration. For the Y and crossbar configurations, the WSS of the right PCA obviously decreased. The overall pressure change was less than 1 % for the various configurations, with the Y configuration having the highest pressure increase (0.728 %). Simulation results demonstrate obvious differences among the various stent configurations in a wide-neck basilar tip aneurysm.

Greater Flow Diversion with the LVIS Stent vs the Enterprise Stent Regarding Basilar Tip Aneurysm Hemodynamics

“…For the posterior circulation aneurysms, especially the basilar tip aneurysm, various stent configurations including half-Y Y crossbar and T could be implanted. Previous hemodynamic studies demonstrated obvious differences between Enterprise stent configurations in wide-necked basilar tip aneurysms [8]. However, compared to the Enterprise stent, the LVIS stent has lower recanalization rate and a higher occlusion rate [2,3].…”

“…In our simulations, a novel virtual stenting workflow [8,9] was used to deploy the Enterprise and LVIS stents (Figure 1). The simulation consists of the following three steps: (1) Pre-processing, which separates the parent artery from the aneurysm, and produces a simplex mesh structure along the vessel centerline position;…”

What does computational fluid dynamics tell us about intracranial aneurysms? A meta-analysis and critical review

“…Ideal models are often based on assumed geometry with anatomically relevant dimensions used to study the morphological patterns [129][130][131][132][133] and Neuroendovascular device efficacy. 134,135 Some of the ideal model geometries are actually constructed from averaging of patientspecific dimensions across a specific population to compare the relevance of gender, 136 morphology 137 or complex cases of IA. 138 Patient-specific models are often constructed from DSA images, 139 and then converted to volume meshing suitable for any adequate CFD solver.…”

A Computational Hemodynamics Analysis on the Correlation Between Energy Loss and Clinical Outcomes for Flow Diverters Treatment of Intracranial Aneurysm

“…The two types of FDs with most clinical data in the literature are the Pipeline Embolization Device [6,7] (PED; Covidien Vascular Therapies, Mansfield, MA, USA) and Silk stent [8] (Balt, Montmorency, France). Different FD configurations will have an observable effect on the hemodynamics [9]. In this paper, the focus will be placed on PED.…”

“…9) where v  = inflow velocity vector on the neck orifice (m s -1 ), A  = area vector normal to the neck orifice (mm 2 ). The area-weighted average of γ average is defined as…”