Mechanical thrombectomy for M2 occlusion sharply branching from M1 near an aneurysm

Abstract

Background: Mechanical thrombectomy (MT) for vessel occlusion near an aneurysm carries the risk of aneurysm rupture due to mechanical stress during the procedure. We report a case of MT performed for M2 occlusion that sharply branched from M1 near the aneurysm.

Case description: A 73-year-old woman presented with a left middle cerebral artery (MCA) bifurcation aneurysm, exhibiting right-sided hemiparesis and aphasia. MT was performed for M2 occlusion, which sharply branched from M1 near the MCA bifurcation aneurysm. Lesion crossing was carefully performed, and a stent retriever was deployed at the occlusion site. Using a stent retriever as an anchor, a bent-tip aspiration catheter was guided past the aneurysm to the proximal end of the thrombus. A combined technique, during which the stent retriever was retracted into the aspiration catheter, was used. This approach minimized mechanical stress on the aneurysm and helped achieve effective recanalization.

Conclusion: In cases of vessel occlusion with a proximal cerebral aneurysm, a combined technique of retracting a stent retriever into an aspiration catheter positioned distal to the aneurysm after stent retriever deployment may help reduce the mechanical stress on the aneurysm during MT and provide a safer approach.

Keywords: Aneurysm; Aspiration catheter; Combined technique; Stent retriever; Thrombectomy.

Figure 1:

Initial imaging findings before endovascular surgery. (a) Axial image of magnetic resonance (MR) angiography reveals a left middle cerebral artery bifurcation aneurysm (arrowhead). (b) MR IMAGING Volume I Sotropic Tse Acquisition reveals no evidence of aneurysm embedding (arrowhead) into the cerebral lobes. (c) Pre-onset computed tomography (CT) angiography indicates a steep branching angle of the left M2 inferior trunk (arrow), arising from the aneurysm, relative to M1. (d) At onset, diffusion-weighted imaging (DWI) shows faint hyperintensity in the perfusion territory of the left middle cerebral artery. The DWI-Alberta stroke program early CT score is 7 points. (e) At onset, CT angiography reveals occlusion of the left M2 inferior trunk (arrow). The origin of the occluded vessel is not visible.

Figure 2:

Imaging findings during endovascular surgery. (a and b) Left internal carotid artery angiography depicts a middle cerebral artery bifurcation aneurysm and occlusion of the left M2 inferior trunk. (b) is a magnified view of the frontal working angle. (c) A Headway17 microcatheter, steam-shaped into a pigtail configuration, is positioned proximal to the occlusion site. (d) A CHIKAI10 microguidewire and Headway17 microcatheter are advanced distally into the left M2 inferior trunk. (e) During advancement of the SOFIAFLOW aspiration catheter, anchored by a stent retriever deployed from the M2 inferior trunk to the distal M1, the aspiration catheter could not be advanced due to its orientation toward the aneurysm. (f) After switching to a bent-tip Vecta46 aspiration catheter, successful navigation to the proximal end of the thrombus in the left M2 inferior trunk was achieved. (g) The SolitaireX 3 mm × 40 cm stent retriever is retracted into the Vecta46 aspiration catheter. Angiography confirms that the Vecta46 does not interfere with the aneurysm. (h) Retrieved red thrombus. (i) Effective recanalization is achieved despite the continued occlusion of a branch of the left M2 inferior trunk. (j) Left internal carotid artery angiography shows thrombolysis in cerebral infarction grade 2b recanalization.

Figure 3:

Postoperative imaging findings. (a) Non-contrast head computed tomography (CT) on the day after surgery shows a small amount of subarachnoid hemorrhage in the left Sylvian fissure (arrowhead). (b) Diffusion-weighted imaging on the day after surgery reveals an infarction in the left M2 inferior trunk territory. (c) Magnetic resonance angiography on the day after surgery demonstrates patency of the left M2 inferior trunk.