Endovascular treatment of a ruptured blister-like aneurysm at an azygos anterior cerebral artery: A case report and review of the literature

Abstract

Background: Endovascular treatment for a ruptured blister-like aneurysm (BLA) has recently become a hopeful approach. BLAs are usually located on the dorsal wall of the internal carotid artery, whereas one located on the azygos anterior cerebral artery (ACA) is so rare, it has never been reported. We report a case of a ruptured BLA arising at the distal bifurcation of an azygos ACA treated by stent-assisted coil embolization.

Case description: A 73-year-old woman presented with a disturbance of consciousness. Computed tomography showed diffuse subarachnoid hemorrhage, which was observed to be particularly dense in the interhemispheric fissure. Three-dimensional rotation angiography showed a tiny and conical bulge on the distal bifurcation of the azygos trunk. Follow-up digital subtraction angiography performed on day 4 showed enlargement of the aneurysm, and a BLA arising at the azygos bifurcation was diagnosed. Stent-assisted coiling (SAC) was performed using a low-profile visualized intraluminal support (LVIS) Jr. stent, which was implanted from the left pericallosal artery to the azygos trunk. Follow-up angiography showed that the aneurysm thrombosed gradually and reached complete occlusion 90 days after onset.

Conclusion: SAC for a BLA at the distal bifurcation of an azygos ACA might be an effective treatment option leading to early complete occlusion, but thrombus formation as an intraoperative complication should be noted in the BLA at the bifurcation or the peripheral artery, as in the present case.

Keywords: Azygos anterior cerebral artery; Blister-like aneurysm; Endovascular treatment.

Figure 1:

(a) Axial computed tomography (CT) on the initial visit shows diffuse subarachnoid hemorrhage distributed mainly at the interhemispheric fissure. (b) CT angiography shows an azygos anterior cerebral artery (ACA) with hypoplasia of the A1 segment of the right ACA. (c) Three-dimensional rotational angiography (3D-RA) with injection from the left internal carotid artery shows a tiny bulge on the distal bifurcation of an ACA on day 0. This small aneurysm rides from the distal end of the azygos trunk to the left pericallosal artery. (d) The follow-up 3D-RA on day 4 shows obvious enlargement of the aneurysm.

Figure 2:

Stent-assisted coiling was subsequently performed on the same day as the follow-up digital subtraction angiography (DSA). (a) Left carotid angiography at a working angle shows a blister-like aneurysm (BLA) (black arrow) at the distal bifurcation of the azygos trunk and a Headway 17 microcatheter placed on the left pericallosal artery for stenting. (b) The fluoroscopic image demonstrates two loops of a single GalaxyG3 coil inside the BLA (black arrow) and the implanted LVIS junior stent from the left pericallosal artery to the azygos trunk (long thin black arrow). (c and d) The final DSA shows immediate complete occlusion of the BLA (black arrow) and thrombus at the origin of a right pericallosal artery (black arrowhead).

Figure 3:

Magnetic resonance imaging-diffusion-weighted imaging shows multiple spotty high intensities in the bilateral anterior cerebral artery region.

Figure 4:

The follow-up digital subtraction angiography (DSA). (a and b) The DSA 14 (a) and 30 (b) days after onset shows the residual contrast effect and gradual thrombosis within the dome of a blister-like aneurysm (black arrow in (a) and (b)). (c) The DSA at 90 days shows complete obliteration (black arrow).