Acute Internal Carotid Artery Embolism Combined with Chronic Middle Cerebral Artery Occlusion: A Report of Two Cases

Background Endovascular thrombectomy (EVT) is the preferred treatment strategy for acute anterior circulation large vessel occlusion (LVO) stroke. Acute LVO most commonly arises from acute embolism or in-situ thrombosis superimposed on atherosclerotic stenosis, while embolic events over pre-existing chronic vascular occlusion are rare. Distinguishing between acute embolism and embolic events superimposed on chronic occlusion is crucial for treatment decision-making. Case presentation We report two cases of acute internal carotid artery (ICA) terminal occlusion diagnosed by preoperative computed tomography angiography (CTA). In Case 1, the microguidewire failed to traverse the middle cerebral artery (MCA) occlusion segment; chronic MCA occlusion was suspected based on preoperative CT perfusion (CTP) and multimodal imaging, so the thrombectomy stent was deployed in the anterior cerebral artery (ACA), achieving successful recanalization. In Case 2, the deployed thrombectomy stent failed to fully expand in the MCA, indicating chronic occlusion; semi-deployment and retrieval of the stent achieved successful recanalization. Conclusion For patients with acute ICA occlusion, the possibility of concomitant chronic MCA occlusion should be considered. Multimodal imaging evaluation and intraoperative tactile feedback can help identify this complex condition and guide treatment strategy.