Delayed Rupture of an Anterior Communicating Artery Pseudoaneurysm Caused by Distal Occlusion Thrombectomy Using a Stent Retriever: A Case Report and Mechanism of Injury

Abstract

We report a case of delayed rupture of an anterior communicating artery (Acom) pseudoaneurysm following mechanical thrombectomy (MT) of a distal artery occlusion using a stent retriever. An elderly patient with right hemiparesis showed left proximal internal cerebral artery and middle cerebral artery occlusions. During MT, a fragmented thrombus moved to the anterior cerebral artery (ACA). A stent retriever was deployed to the occluded ACA, and the Acom and proximal ACA segment were significantly straightened. Additionally, we attempted a blind exchange mini-pinning (BEMP) technique, but a subarachnoid hemorrhage (SAH) occurred. Bleeding was almost entirely absorbed 9 days after the procedure, but the SAH recurred at 20 days, and computed tomography angiography revealed a new pseudoaneurysm formation in the Acom. We suggest that the proposed mechanism of pseudoaneurysm formation was likely due to the dislocation and avulsion of the Acom perforators when the ipsilateral ACA was pushed and pulled during MT.

Keywords: Acute ischemic stroke; Pseudoaneurysm; Subarachnoid hemorrhage; Thrombectomy.

Fig. 1.

Angiographies and follow-up brain computed tomography angiography (CTA) of the patient. (A) After aspiration thrombectomy using a Penumbra pump in the left proximal internal cerebral artery (ICA), the left ICA angiography shows left middle cerebral artery (MCA) M1 and anterior cerebral artery (ACA) (arrows) occlusion. We performed the Solumbra technique (using Solitaire stent retriever [4×40 mm] and 5-Fr SOFIA intermediate catheter) in the left MCA M1 segment and the MCA was fully recanalized. (B) After deploying the stent retriever (Solitaire 4×40 mm, white arrow) to the distal ACA occlusion site, the blind exchange mini-pinning (BEMP) technique was tried. The left ICA angiography shows a heavily dislocated left ACA A2 segment to the medial side (white arrow), and the change in angle between distal ICA and ACA A1 segment (arrowheads). The anterior communicating artery (Acom) was also dislocated distally (black arrow). Note the change in angles between ACA A1 and A2 segments (double black arrows) before (A) and after (B) deploying the stent retriever. (C, D) Comparing lateral projection of left ICA angiographies before (C) and after (D) stent deployment in the left ACA occlusion site (black arrow), ipsilateral distal ICA and ACA A1 segments were also straightened (arrowheads). White arrow in (D) indicates the push wire of the stent retriever. (E) Working projection of left ICA angiography while removing the microcatheter over the push wire of the stent retriever shows that the angle formed by the push wire suddenly straightened (arrowheads), with no antegrade flow in the Acom and ipsilateral ACA (white arrow). (F, G) Subarachnoid hemorrhage (SAH) was confirmed by a flat panel computed tomography. The white arrows indicate SAH in bilateral interhemispheric and the Sylvian cisterns, and arrowheads indicate the push wire (F) and the stent strut of Solitaire stent retriever (G). (H) Final angiography shows fully recanalized state of left MCA and ACA. There was no visible aneurysm in Acom. (I) On the 20th day, SAH in the interhemispheric and right Sylvian cistern (black arrows) were observed again. (J) On that day, Acom pseudoaneurysm (white arrow) was observed on CTA.

Fig. 2.

A proposed mechanism of anterior communicating artery (Acom) pseudoaneurysm formation. (A, B) The angle between the left anterior cerebral artery (ACA) A1 and A2 (double black arrow), and the angle in proximal ACA A1 segment (black arrow) were changed after deploying the stent retriever, and Acom perforators also dislocated distally (arrowheads). (B, C) When attempting the blind exchange mini-pinning (BEMP) technique, microcatheter (yellow catheter) removal was attempted, and the stent retriever was pulled and pushed a lot (blue arrows) along the push wire. Eventually, Acom perforators were ruptured (arrowheads).