Vessel wall injury after stent retriever thrombectomy for internal carotid artery occlusion with a duplicated middle cerebral artery.

BACKGROUND: There is increasing experimental evidence that stent retriever thrombectomy (SRT) may cause arterial wall damage, although histopathological findings focused on vessel wall injury after SRT have not fully been reported in humans.

CASE DESCRIPTION: We describe an autopsy case of an 82-year-old woman who presented with acute left intracranial internal carotid artery (ICA) occlusion and received SRT. When we attempted to catheterize the M1 segment of the normal middle cerebral artery (MCA), we were not aware of a duplicated MCA, and the microcatheter was advanced into the main MCA trunk with a smaller caliber than that of the normal M1 segment. A 6-mm Trevo thrombectomy device was deployed from the main MCA trunk, but was insufficiently expanded in the MCA segment. Two passes with a Trevo resulted in failed recanalization. The patient died on postoperative day 4 because of extensive infarction. Autopsy revealed a duplicated MCA and subintimal arterial dissection in the proximal segment of the main MCA trunk. Supraclinoid ICA also revealed endothelial denudation and mural thrombus.

CONCLUSIONS: We provide a histopathological report of vessel wall injury after SRT causing failed recanalization. Anatomical variations of the MCA should be considered when selecting suitable thrombectomy devices, in order to avoid vessel wall injury.