Endovascular treatment for secondary basilar occlusion caused by spontaneous thrombus migration from the vertebral artery: Two case reports.

Thrombus migration is a well-known clinical condition that occurs before mechanical thrombectomy and after intravenous thrombolysis in patients with anterior circulation strokes. Although thrombus migration from the vertebral artery (VA) can result in life-threatening basilar artery (BA) occlusion, its occurrence in the posterior circulation has rarely been discussed. Two patients with secondary BA occlusion caused by spontaneous thrombus migration from the VA are presented. A 60-year-old man with a left cerebellar infarction secondary to ipsilateral VA occlusion was admitted to our hospital 8 hours after onset, with a National Institute of Health Stroke Scale (NIHSS) score of 4. The patient became comatose 3.5 hours after arrival owing to subsequent BA occlusion. He was successfully treated with mechanical thrombectomy. A 74-year-old man with right cerebellar infarction secondary to ipsilateral VA occlusion was admitted to our hospital 26 hours after onset, with an NIHSS score of 3. He became comatose 1 hour after arrival owing to BA occlusion and was treated with thrombectomy, followed by internal and external decompression. Despite the mild symptoms of VA occlusion and consequently delayed admission to the hospital, stroke physicians should be aware that spontaneous thrombus migration from the VA to the BA can result in a life-threatening presentation.