Treatment of wide-necked intracranial aneurysms with a self-expanding stent system: initial clinical experience

Abstract

Background and purpose: Currently available stents for intracranial use usually are balloon-expandable coronary stents that carry the risk of damaging a dysplastic segment of the artery, with potential vessel rupture. We assessed the technical feasibility and efficacy of the combined application of a flexible, self-expanding neurovascular stent and detachable coils in the management of wide-necked intracranial aneurysms in humans.

Methods: Four consecutive patients with a wide-necked intracranial aneurysm were treated with a combined approach that consisted of delivery of a flexible self-expanding neurovascular stent through a microcather to cover the neck of the aneurysm and subsequent filling of the aneurysm with coils through the stent interstices. The aneurysms were located at the internal carotid artery (n=2) and the basilar tip encroaching the P1 segment (n=2). Previous attempts with conventional endosaccular coil packing alone failed in all cases.

Results: Stent placement in the desired position with complete or nearly complete occlusion of the aneurysms was feasible in all patients. In one patient, aneurysm perforation with the microcatheter occurred and necessitated ventricular drainage, which led to a large parenchymal and intraventricular hemorrhage because of the strong anticoagulation regimen. Six-month follow-up demonstrated no focal neurologic sequelae in any of the patients, except slight memory dysfunction in the patient with bleeding.

Conclusion: Preliminary data demonstrate that this extremely flexible stent is technically easy to deploy and can be easily and safely maneuvered through severely tortuous vessels, enabling the treatment of intracranial wide-necked aneurysms. The combination of endovascular reconstruction of the parent vessel with use of a self-expanding stent followed by coil embolization offers a promising therapeutic alternative for wide-necked aneurysms not amenable to coil embolization alone. Although immediate angiographic results are promising, long-term angiographic and clinical follow-up is essential to determine permanent vessel patency and aneurysm occlusion rate.

Fig 1.

Photograph of the self-expanding stent demonstrates the extreme flexibility of the stent system.

Fig 2.

Schematic illustrates the combined treatment of primary stent placement and subsequent coil embolization for wide-necked aneurysms.

Fig 3.

Case 1. Wide-necked paraophthalmic aneurysm (dome, 5.5 × 8 mm; neck, 5 mm). A and B, DSA images obtained before (A) and after (B) combined therapy with the self-expanding stent and GDCs demonstrate complete obliteration. The patient had two additional aneurysms (at the AcomA and basilar artery) previously treated with GDCs alone. C and D, Source images of time-of-flight MR angiography reveal no stent-related artifacts and normal flow-void signal intensity of the internal carotid artery. Arrows in D indicate coil mass. E, Follow-up angiogram after 6 months reveals complete aneurysm occlusion.

Fig 4.

Case 2. A, Angiogram reveals previously coiled recurrent aneurysm (arrows) of the cavernous internal carotid artery. B, Angiogram obtained after stent deployment shows immediate stasis of the contrast material. C, Angiogram obtained after coiling through the stent interstices shows that the aneurysm is subtotally occluded. D, Further thrombosis is noted after 6 months.

Fig 5.

Case 3. A, Anteroposterior and B, lateral DSA views demonstrate a broad-based, previously clipped, recurrent basilar tip aneurysm encroaching on the left P1 segment. C, Angiogram reveals immediate stasis of contrast material in the aneurysm after stent deployment. D, Angiogram reveals extravasation of contrast material after aneurysm perforation with the microcatheter (arrows). E, Posteroanterior and F, lateral final angiograms after treatment show complete obliteration. G, Angiogram shows that the right posterior cerebral artery is opacified via the internal carotid artery.

Fig 6.

Case 4. A, Posteroanterior and B, oblique DSA views show a previously coiled, multilobulated, recurrent basilar tip aneurysm encroaching the left P1 segment. C, Unsubtracted image demonstrates the proximal and distal markers (arrows) of the self-expanding neurovascular stent positioned with the distal end in the left P1 segment and with the proximal end in the midbasilar artery. D, Final oblique angiographic view after treatment demonstrates complete obliteration of the aneurysm. E, Follow-up angiogram reveals that the aneurysm remained occluded 6 months later