Ischemia in the territory of a hypoplastic vertebrobasilar system

Background: Congenital variations in the configuration and size of the cere bral vessels may predispose to ischemic stroke. Objectives/Methods: To illu strate that a hypoplastic basilar artery may lead to posterior circulation ischemia in adults, eight cases are reported from two university medical ce nters. Results: Five men and three women with a mean age of 49.8 years are reported. Four of the patients had other conventional stroke risk factors. Two patients had brainstem strokes, and six had TIA. All patients had hypop lastic basilar arteries. Seven patients had at least one hypoplastic verteb ral artery (bilateral in five cases), and six patients had both posterior c erebral arteries originating from the internal carotid arteries. Conclusion s: A hypoplastic basilar artery is frequently accompanied by vertebral arte ry hypoplasia, and this can predispose adults to posterior circulation isch emia. This entity can be suspected on the basis of MR angiogram, but conven tional angiography will provide definitive diagnosis. Optimal medical and s urgical treatment of this condition is unresolved.