Abstract WP142: Low Risk Of Posterior Circulation Stroke In Ischemic Stroke Patients With Vertebral Artery Ositium Stenosis

Backgrounds Atherosclerosis of vertebrobasilar artery is a major cause of the ischemic stroke in the posterior circulation. Vertebral artery ostium stenosis (VAOS) is occasionally observed in patients with acute ischemic stroke in anterior or posterior circulation. However, VAOS as a risk for stroke recurrence, especially for the posterior circulation stroke, has not been well studied. This study was performed to determine long-term outcome and clinical significance of VAOS in acute ischemic stroke patients. Methods As a prospective observational study of single stroke center registry, we studied risk of recurrent stroke and vascular outcome in acute ischemic stroke patients with VAOS, recruited consecutively from December 2007 to December 2010. VAOS was defined as more than 50% stenosis of either vertebral artery ostium on a contrast-enhanced MRA. Vascular risk factors and long-term outcome including recurrent stroke, cardiovascular event, vascular mortality, or all-cause mortality were investigated. Results Of 773 acute ischemic stroke patients, underwent contrast-enhanced MRA, 149 (19.2%) had more than 50% VAOS (age, 70±10 years). All patients had intensive medical treatment and 11 patients underwent angioplasty and stenting. During 327 patient-years of follow-up (mean, 2.2 years), there were 8 ischemic (3 in posterior circulation, 5 in anterior circulation), 5 hemorrhagic, and 2 unknown stroke. The annual rate of events were 1.36% for posterior circulation ischemic stroke, 3.64% for all ischemic stroke, 5.91% for all stroke, 1.36% for vascular death, and 9.55% for all cause mortality. Symptomatic VAOS, concomitant stenosis of other vertebrobasilar arteries or carotid arteries, or stroke subtype was not associated with long-term outcome. Conclusions Long-term outcome of acute ischemic stroke patients with more than 50% VAOS was favorable on intensive medical treatment and selective angioplasty and stenting. Vertebral artery ostium stenosis may not be a major risk factor for the recurrent ischemic stroke in the posterior circulation.