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.