Mechanical Thrombectomy for Azygos Anterior Cerebral Artery Occlusion: A Case Report and Literature Review.

Objective: Azygos anterior cerebral artery (ACA) is a well-known anomaly of the second segment of the ACA. Although cases of intracerebral aneurysms related to this anomaly have been reported, acute ischemic stroke (AIS) related to the azygos ACA is extremely rare. Case Presentation: An 84-year-old man developed disturbance of consciousness (Glasgow Coma Scale [GCS] E3V1M5), quadriparesis and aphasia, with a National Institutes of Health Stroke Scale (NIHSS) score of 32. Magnetic resonance imaging (MRI) showed no early ischemic changes, although a head magnetic resonance angiogram (MRA) demonstrated a single A2 trunk without any A3 branches that were suspected bilateral ACA occlusions. Mechanical thrombectomy for the occluded A2 trunk with contact aspiration using a Penumbra 4MAX aspiration catheter was performed, and the clot was retrieved and complete recanalization was achieved after two attempts (Thrombolysis in Cerebral Infarction scale 3) without any complications (onset to recanalization time: 187 min). The final angiogram demonstrated the recanalization of the single A2 and bilateral A3 branches, so we diagnosed as azygos ACA occlusion. MRI performed the next day revealed several small infarctions in bilateral frontal lobes, but ischemic symptoms gradually improved. NIHSS score decreased to two in 2 weeks and modified Rankin Scale (mRS) score at 90 days was one. Conclusion: In this case, occlusion of the azygos ACA led to a large ischemic penumbra that spread widely and bilaterally in the ACA area, resulting in sudden onset of severe ischemic symptoms, including quadriparesis and aphasia. However, due to complete and rapid recanalization with contract aspiration, a large part of the ACA territory bilaterally was salvaged and the patient recovered extremely well.