Patency of Posterior Circulation Branches Covered by Flow Diverter Device: A Hemodynamic Study.

Xinzhi Wu,Xinjian Yang,Zhongbin Tian,Yisen Zhang,Junfan Chen,Jian Liu,Wenqiang Li,Yangyang Zhou,Ying Zhang,Shiqing Mu

doi:10.3389/fneur.2019.00658

Abstract

Objective: Flow diverter devices are increasingly used in the treatment of posterior circulation aneurysms, sometimes necessarily involving ostia of side branches and perforators. The aim of this study was to identify the hemodynamic influence of flow diverters on side branches and perforators of the posterior circulation.Methods: We performed a retrospective study of consecutive patients treated by a flow diverter device for posterior circulation aneurysms with anterior inferior cerebellar artery (AICA) or posterior inferior cerebellar artery (PICA) involvement. Computational fluid dynamics (CFD) were used to discern hemodynamic changes of branches after deployment of the flow diverter.Results: We studied 18 branches from 17 patients (mean age, 50.72 ± 8.17 years). No branches were occluded on immediate angiography and later follow-up. Average flow velocity in aneurysms decreased from 0.077 ± 0.065 m/s to 0.025 ± 0.025 m/s (p < 0.01). Average flow velocity in branch ostia decreased from 0.29 ± 0.14 m/s to 0.27 ± 0.16 m/s (p = 0.189). The difference in flow velocity reduction ratio between aneurysms and branches was statistically significant (68.8 vs. 9.5%; p < 0.001). The mean pressure in branch ostia increased from 10,717.4 ± 489.0 to 10,859.0 ± 643.4 Pa (p < 0.01).Conclusion: While a flow diverter device is capable of slowing down aneurysmal inflow, it is unable to block the flow into branches and perforators when used in the treatment of posterior circulation aneurysms; flow velocity in branches even increased in some cases. With a low branch occlusion ratio, it may be acceptable to cover posterior circulation branches and perforators if unavoidable.

Highlights

Flow diverter devices (FDs) are commonly used for the treatment of intracranial aneurysms [1, 2]
Aneurysmal inflow can be altered by an FD and the process of thrombogenesis promoted
The inclusion criteria were: [1] unruptured posterior circulation aneurysms; [2] the aneurysms were treated by only one pipeline embolization device (PED), and anterior inferior cerebellar artery (AICA) or posterior inferior cerebellar artery (PICA) were covered by the stent at the same time; [3] a reconstructed 3D model of the ipsilateral vertebral artery was acquired; [4] the landing zone of the PED had to be identified on digital subtraction angiography (DSA) images to ensure that branches were covered by the PED; [5] patients were followed up with a control angiogram

Summary

Introduction

Flow diverter devices (FDs) are commonly used for the treatment of intracranial aneurysms [1, 2]. Aneurysmal inflow can be altered by an FD and the process of thrombogenesis promoted. Aneurysms treated by FDs are more inclined to achieve complete occlusion compared with other endovascular therapies. The 5-year occlusion rate was recently reported as 95.2% [3]. The pipeline embolization device (PED; Medtronic, Minneapolis, MN, USA) is a type of FD initially approved to treat internal carotid artery aneurysms, for which it was demonstrated to be safe and effective [4, 5].

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Discussion

Conclusion