Risk of Branch Occlusion and Ischemic Complications with the Pipeline Embolization Device in the Treatment of Posterior Circulation Aneurysms

Abstract

Background and purpose: Flow diversion with the Pipeline Embolization Device is increasingly used for endovascular treatment of intracranial aneurysms due to high reported obliteration rates and low associated morbidity. While obliteration of covered branches in the anterior circulation is generally asymptomatic, this has not been studied within the posterior circulation. The aim of this study was to evaluate the association between branch coverage and occlusion, as well as associated ischemic events in a cohort of patients with posterior circulation aneurysms treated with the Pipeline Embolization Device.

Materials and methods: A retrospective review of prospectively maintained databases at 8 academic institutions from 2009 to 2016 was performed to identify patients with posterior circulation aneurysms treated with the Pipeline Embolization Device. Branch coverage following placement was evaluated, including the posterior inferior cerebellar artery, anterior inferior cerebellar artery, superior cerebellar artery, and posterior cerebral artery. If the Pipeline Embolization Device crossed the ostia of the contralateral vertebral artery, its long-term patency was assessed as well.

Results: A cohort of 129 consecutive patients underwent treatment of 131 posterior circulation aneurysms with the Pipeline Embolization Device. Adjunctive coiling was used in 40 (31.0%) procedures. One or more branches were covered in 103 (79.8%) procedures. At a median follow-up of 11 months, 11% were occluded, most frequently the vertebral artery (34.8%). Branch obliteration was most common among asymptomatic aneurysms (P < .001). Ischemic complications occurred in 29 (22.5%) procedures. On multivariable analysis, there was no significant difference in ischemic complications in cases in which a branch was covered (P = .24) or occluded (P = .16).

Conclusions: There was a low occlusion incidence in end arteries following branch coverage at last follow-up. The incidence was higher in the posterior cerebral artery and vertebral artery where collateral supply is high. Branch occlusion was not associated with a significant increase in ischemic complications.

Fig 1.

Digital subtraction angiography shows a basilar tip saccular aneurysm before treatment with the Pipeline Embolization Device (A). The PED was placed spanning the lower part of the basilar truck into the left posterior cerebral artery. On 4-month follow-up (B), DSA shows complete aneurysm occlusion, along with complete occlusion of the right PCA. The anterior inferior cerebral arteries and superior cerebellar arteries remained patent. The patient remained neurologically intact.

Fig 2.

Digital subtraction angiography shows 2 basilar trunk saccular aneurysms before treatment with the Pipeline Embolization Device (A). The PED was placed spanning the AICA bilaterally. On follow-up DSA (B), there was complete occlusion of the left AICA. The patient had a symptomatic left-sided pontine stroke that remained symptomatic at 10-month follow-up (C).