SUMMARY:Vertebral artery recanalization in symptomatic stenosis/occlusion remains controversial, as no definite evidence exists regarding this topic. There are only a few reports regarding the feasibility and safety of recanalization in the first segment of the vertebral artery with atherosclerotic vertebral ostial occlusion. We report our experience treating first segment occlusion in 8 patients and present a balloon protection technique used to reduce the thromboembolic burden during the stent placement procedure. The outcome at 3 months showed an mRS Յ2 except for a patient with a poor initial status with basilar artery occlusion. Revascularization of a rather long first segment occlusion is technically feasible and can be safely performed by use of embolic protection methods. A therosclerotic lesions of the vertebral artery (VA) origin are a potential cause of posterior circulation ischemia, which has approximately a 20% to 50% risk for vertebrobasilar TIA or stroke. ABBREVIATIONS:1 The VA ostium is known to be the most common site for atherosclerosis of the posterior circulation. 2 Patients with symptomatic severe (Ͼ 70%) ostial VA stenosis face an 11% annual risk for recurrent stroke or TIA while receiving medical treatment. 3Early understanding of the stroke mechanism of VA ostial lesions was focused on their hemodynamic nature, which commonly presents with TIA including dizziness.4 After a few case series that described an embolic infarct originating from vertebral ostial occlusive disease, 5 artery-to-artery embolism was also considered as an important cause of the stroke mechanism in lesions in the first segment of the VA (V1). 6 A large series of patients revealed that half of the artery-to-artery embolic strokes in the posterior circulation were the result of VA ostial lesions. 7 The presence of a clot in the vertebral ostial plaque provides the causeand-effect relationship between vertebral arterial ostial lesions and posterior circulation stroke. 8 Even a large ulcer in the vertebral arterial ostium has been described as adding to the possibility of the vertebral arterial ostium as a source of emboli. 9The optimal treatment of patients with symptomatic severe ostial VA stenosis is still unclear.3 The only randomized trial comparing endovascular with medical treatment is the Carotid and VA Transluminal Angioplasty Study. 10 This study did not show a separate result for the small number of its patients (nϭ16) with VA stenosis, though it failed to demonstrate the benefit of angioplasty of carotid and vertebral stenosis. Although several articles have dealt with revascularization of vertebral ostial lesions, they mostly have described revascularization of vertebral arterial stenosis.11 To our knowledge, only a few case reports have demonstrated anecdotal evidence of revascularization for vertebral ostial occlusion. 12 Therefore, we present the revascularization procedure and the outcome of vertebral ostial occlusion in strokes related to artery-to-artery embolism. MATERIALS AND METHODS Case SeriesEight...