Supplementary Material for: Basilar Artery Dissection: Series of 12 Consecutive Cases and Review of the Literature

<i>Background:</i> Current knowledge on primary or isolated basilar artery dissection (IBAD) is limited to case vignettes and small patient series. <i>Objective:</i> To delineate the frequency and clinical presentations of IBAD along with short-term outcome, specific prognosis and targeted management. <i>Methods:</i> Data were derived from a series of 12 consecutive patients and a review of 88 cases reported in the literature. In all the cases, the dissection was confined to the basilar artery. <i>Results:</i> Disease incidence was estimated at 0.25 per 100,000 person-years. IBAD accounted for roughly 1.0% of all subarachnoid hemorrhage events and for no less than 10.5 and 4.5% of posterior circulation and brain-supplying artery dissections, respectively. The main clinical presentations were subarachnoid hemorrhage (46%) and posterior circulation brain ischemia (42%). Subarachnoid hemorrhage typically manifested at a higher age than brain ischemia (mean age, 48.9 vs. 41.4 years) and was more prevalent among women. Rebleedings related to pseudoaneurysm formation in patients with subarachnoid hemorrhage and recurrent ischemia in stroke patients were common in the acute phase (26.1 and 33.3%, respectively) but were rare in the long term. The outcome was generally favorable in stroke patients but variable in subarachnoid hemorrhage (case fatality rate, 21.7%). The mainstay of therapy for subarachnoid hemorrhage related to IBAD was endovascular occlusion of the aneurysm pouch whereas stroke patients were usually put on anticoagulants. <i>Conclusions:</i> IBAD is probably an underrecognized disease with heterogeneous clinical presentation and prognosis. It should be considered as a differential diagnosis in peritruncal subarachnoid hemorrhage, classic subarachnoid hemorrhage and posterior circulation stroke, especially in young individuals. Case management is challenging and has to be tailored to each patient.