Expanding Indications for Flow Diverters: Distal Aneurysms, Bifurcation Aneurysms, Small Aneurysms, Previously Coiled Aneurysms and Clipped Aneurysms, and Carotid Cavernous Fistulas

Abstract

Flow diverter devices have gained wide acceptance for the treatment of unruptured intracranial aneurysms. Most studies are based on the treatment of large aneurysms harboring on the carotid syphon. However, during the last years the "off-label" use of these stents has widely grown up even if not supported by randomized studies. This review examines the relevant literature concerning "off-label" indications for flow diverter devices, such as for distal aneurysms, bifurcation aneurysms, small aneurysms, recurrent aneurysms, and direct carotid cavernous fistulas.

Keywords: Bifurcation aneurysm; Carotid cavernous fistula; Distal aneurysm; Flow diverter device; Intracranial aneurysm; Recurrent aneurysm.

FIGURE 1.

Ruptured dissecting aneurysm of the right distal pericallosal artery in a 45-yr-old man. Angiography shows the aneurysm with ill-defined neck and stagnating flow inside the sac A (lateral view). Unsubtracted angiography from the microcatheter B shows neck coverage after deployment of a 2.5-8/13 FRED Jr (MicroVention). Six-month angiographic follow-up C (lateral view) shows occlusion of the aneurysm and patency of the stent.

FIGURE 2.

Small right pericallosal artery in a 54-yr-old woman. Coiling had been attempted, but it was unfeasible because of the callosomarginal artery origin from the sac A (angiography lateral view). A 2.5-20 PED was deployed, covering the aneurysmal neck B (road map during deployment). The 6-mo angiographic follow-up shows occlusion of the aneurysm. The patient was asymptomatic. The callosomarginal artery was patent, but it was much narrowed and it presented a tight stenosis at the origin C (lateral view).

FIGURE 3.

Asymptomatic fusiform aneurysm of the right MCA in a 59-yr-old man. The anterior temporal artery originates from the aneurysmal tract A (angiography in right oblique view) and B (frontal view before stent deployment). Six-month angiographic follow-up after treatment with PED shows partial reduction of the aneurysm C (angiography in right oblique view) and D (frontal view). The covered anterior cerebral artery is still patent at follow-up.

FIGURE 4.

Illustrative case of a 62-yr-old woman with SAH. Angiography revealed a short M1 segment of the left MCA, harboring a small aneurysm of the superior division (white arrow), a large aneurysm of the second MCA bifurcation (black arrow), and a small AComA aneurysm (dotted arrow) A (obliquefrontal view). The large aneurysm was supposed to be the ruptured one, so it was coiled with deliberate sparing of the base (white arrow) to avoid branches occlusion B (frontal view) and C (oblique view showing the remnant). Flow diversion after 1 mo was planned. The lateral view before the second intervention shows the configuration and size of the MCA candelabra vessels D. A single PED (white arrows) was deployed covering both MCA aneurysms E (unsubtracted frontal view). At 6-mo angiographic follow-up, both MCA aneurysms were occluded, but covered jailed branches were extremely narrowed F (left oblique view) and G (right oblique view). Lateral view of the 6-mo follow-up shows the diffuse narrowing of MCA branches H. Comparison of H with the preflow diversion lateral view D allows recognizing the significant vessels remodeling and the improvement of collateral circulation from ACA pial branches. The patient remained asymptomatic during follow-up.

FIGURE 5.

Ruptured left carotid-ophthalmic aneurysm in a 34-yr-old woman A (angiography in oblique view). Complete occlusion was achieved with balloon assisted coiling B (lateral view). At 6-mo follow-up, a recurrence was found C (frontal view) and D (lateral view), so FDD was planned. Further 6-mo follow-up after flow diversion showed aneurysm occlusion. The coils cast approached the carotid profile, this could indirectly suggest aneurysm shrinkage E (frontal view) and F (lateral view).