Endovascular treatment of cerebral aneurysms using flow-diverter devices: A systematic review

Abstract

Background: Flow-diverter devices (FDDs) are new-generation stents placed in the parent artery at the level of the aneurysm neck to disrupt the intra-aneurysmal flow thus favoring intra-aneurysmal thrombosis.

Objective: The objective of this review article is to define the indication and results of the treatment of intracranial aneurysms by FDD, reviewing 18 studies of endovascular treatment by FDDs for a total of 1704 aneurysms in 1483 patients.

Methods: The medical literature on FDDs for intracranial aneurysms was reviewed from 2009 to December 2014. The keywords used were: "intracranial aneurysms," "brain aneurysms," "flow diverter," "pipeline embolization device," "silk flow diverter," "surpass flow diverter" and "FRED flow diverter."

Results: The use of these stents is advisable mainly for unruptured aneurysms, particularly those located at the internal carotid artery or vertebral and basilar arteries, for fusiform and dissecting aneurysms and for saccular aneurysms with large necks and low dome-to-neck ratio. The rate of aneurysm occlusion progressively increases during follow-up (81.5% overall rate in this review). The non-negligible rate of ischemic (mean 4.1%) and hemorrhagic (mean 2.9%) complications, the neurological morbidity (mean 3.5%) and the reported mortality (mean 3.4%) are the main limits of this technique.

Conclusion: Treatment with FDDs is a feasible and effective technique for unruptured aneurysms with complex anatomy (fusiform, dissecting, large neck, bifurcation with side branches) where coiling and clipping are difficult or impossible. Patient selection is very important to avoid complications and reduce the risk of morbidity and mortality. Further studies with longer follow-up are necessary to define the rate of complete occlusion.

Keywords: Intracranial aneurysm; Silk embolization device; brain aneurysm; endovascular treatment; flow-diverter devices; pipeline embolization device; surpass embolization device.

Figure 1.

Flow-diverter devices approved for the treatment of intracranial aneurysms. Visibility under fluoroscopy: (a) pipeline embolization device (PED); (b) Silk; (c) Flow Re-direction Endoluminal Device (FRED); (d) Surpass; (e) p64.

Figure 2.

Images of a 61-year-old woman harboring a wide-neck left small carotid-ophthalmic aneurysm. Computed tomography angiography (CTA): axial native images (a), two-dimensional (2D) sagittal multi-planar reconstructions (MPRs) (b), three-dimensional (3D) volume rendering (VR) reconstruction (c). Preoperative digital subtraction angiogram (DSA) (d); interventional procedure: Pipeline Embolization Device (PED) deployment (e); nonsubtracted images after deployment: immediate contrast stasis in the sac (f); three-month angiogram (g, h): complete occlusion of the aneurysm.

Figure 3.

Images of a 52-year-old woman with a left small posterior communicating artery aneurysm (white arrow) and a smaller cranial supraclinoid infundibuloma (black arrow). Before (a) and three months after (b) the endovascular procedure with Flow Re-direction Endoluminal Device (FRED).

Figure 4.

Images of a 57-year-old woman harboring a large left carotid-ophthalmic aneurysm (a); Before (a) and nine months after (b) the endovascular procedure with Pipeline Embolization Device (PED).

Figure 5.

Images of a 68-year-old woman harboring a right M1–M2 bifurcation middle cerebral artery (MCA) aneurysm (black arrow) and two small aneurysms of the posterior wall of the supraclinoid internal carotid artery (ICA) (white arrow). Before (a) and six months after (b) the endovascular procedure with two Pipeline Embolization Devices (PEDs).