Effectiveness of mechanical thrombectomy for acute unilateral vertebral artery occlusion with patent basilar artery: Case series and literature review

Objective: Acute unilateral vertebral artery occlusion (VAO) with a patent basilar artery (BA) often results in neurological deterioration due to brainstem infarction from occluded VA perforators, despite comprehensive medical treatment. While recent studies show mechanical thrombectomy (MT) is effective for BA occlusion as well as anterior circulation occlusions, its role in acute unilateral VAO with patent BA remains unclear. This study aims to assess the effectiveness of MT for acute unilateral VAO with patent BA in patients presenting mild symptoms. Methods: We retrospectively reviewed cases of acute VAO with patent BA treated at our institution from April 2016 to March 2023. Patients were assigned to two groups: the MT Group (undergoing MT for unilateral VAO) and the Control Group (receiving medical treatment, including intravenous tissue-plasminogen activator). Clinical and radiological outcomes were compared between groups to evaluate procedural feasibility and safety. Results: Five cases (four males, one female) were included, with a median age of 71 years (IQR: 56-80) and a median NIHSS score of 6 at admission (IQR: 3-11). Three patients underwent MT, and two received conservative treatment. In the MT Group, two patients with successful recanalization experienced no complications or brainstem infarction. One patient with unsuccessful recanalization and both Control Group patients showed early neurological deterioration from brainstem infarction. Conclusions: Acute unilateral VAO with patent BA frequently exacerbates symptoms due to brainstem perforator occlusion, worsening prognosis. Successful VA recanalization may prevent symptomatic brainstem infarction, potentially improving outcomes. Larger prospective studies are warranted.