Combined Effects of Flow Diverting Strategies and Parent Artery Curvature on Aneurysmal Hemodynamics: A CFD Study.

Jinyu Xu,Jian-Min Liu,Ying Yu,Christof Karmonik,Qinghai Huang,Nan Lv,Shengzhang Wang,Zhichen Wu,Josué Sznitman

doi:10.1371/journal.pone.0138648

Jinyu Xu, Jian-Min Liu + Show 7 more

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https://doi.org/10.1371/journal.pone.0138648

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Abstract

PurposeFlow diverters (FD) are increasingly being considered for treating large or giant wide-neck aneurysms. Clinical outcome is highly variable and depends on the type of aneurysm, the flow diverting device and treatment strategies. The objective of this study was to analyze the effect of different flow diverting strategies together with parent artery curvature variations on altering intra-aneurysmal hemodynamics.MethodsFour ideal intracranial aneurysm models with different parent artery curvature were constructed. Computational fluid dynamics (CFD) simulations of the hemodynamics before and after applying five types of flow diverting strategies (single FD, single FD with 5% and 10% packing density of coils, two FDs with 25% and 50% overlapping rate) were performed. Changes in pressure, wall shear stress (WSS), relative residence time (RRT), inflow velocity and inflow volume rate were calculated and compared.ResultsEach flow diverting strategy resulted in enhancement of RRT and reduction of normalized mean WSS, inflow volume rate and inflow velocity in various levels. Among them, 50% overlapped FD induced most effective hemodynamic changes in RRT and inflow volume rate. The mean pressure only slightly decreased after treatment. Regardless of the kind of implantation of FD, the mean pressure, inflow volume rate and inflow velocity increased and the RRT decreased as the curvature of the parent artery increased.ConclusionsOf all flow diverting strategies, overlapping FDs induced most favorable hemodynamic changes. Hemodynamics alterations post treatment were substantially influenced by parent artery curvature. Our results indicate the need of an individualized flow diverting strategy that is tailored for a specific aneurysm.

Highlights

Endovascular treatment for intracranial aneurysms (IAs) has been developed over the past decade as an alternative to surgery
Each flow diverting strategy resulted in enhancement of relative residence time (RRT) and reduction of normalized mean wall shear stress (WSS), inflow volume rate and inflow velocity in various levels
Regardless of the kind of implantation of flow diverter (FD), the mean pressure, inflow volume rate and inflow velocity increased and the RRT decreased as the curvature of the parent artery increased

Summary

Introduction

Endovascular treatment for intracranial aneurysms (IAs) has been developed over the past decade as an alternative to surgery. Stent-alone treatment, as one of the endovascular technique, allows for protection of the parent artery from occlusion, and diversion of the blood flow from the aneurysm [1,2,3,4]. Differences in wire density had been studied using idealized geometries by Seshadhri et al [14] and the FD with the highest wire density was shown to induce the most significant hemodynamic change. It is still not fully understood whether the variations in clinical outcome are related to different morphologies of the parent artery in particular its curvature, or the variable types of the flow diverting device and the particular treatment strategy.

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