Association Between Basilar Artery Hypoplasia and Undetermined or Lacunar Posterior Circulation Ischemic Stroke

Background and Purpose-The aim of the current study was to determine the prevalence of basilar artery hypoplasia (BAH) and to evaluate whether BAH is a possible risk factor for posterior circulation stroke (PCS). Methods-Basilar artery diameter was assessed by MRI in 685 consecutive ischemic stroke patients. BAH frequency, defined as a diameter <2 mm, was measured and compared between anterior circulation stroke and PCS groups. Results-Thirty-seven patients had BAH (5.2%): 15 of 195 (7.7%) in PCS and 22 of 490 (4.5%) in anterior circulation stroke (P=0.2). In undetermined or lacunar stroke patients, BAH frequency was higher in PCS than in anterior circulation stroke (14/97, 14.4% vs 10/216, 4.6%; P=0.005). National Institutes of Health Stroke Scale score was <4 in 65%. Localization of stroke was predominant in pons or cerebellar territories (71.4%). Half of PCS and BAH patients showed small pontic-penetrating arteries infarcts. Conclusions-Our study suggests that BAH is associated with PCS in lacunar or undetermined stroke. Patients often had minor stroke and infarctions that were usually small and frequently located in pontine-penetrating artery territories. (Stroke. 2010;41:2371-2374.)