[Vertebrobasilar insufficiency and carotid artery occlusions: hemodynamic or embolic phenomenon?].

We compared 11 patients with an internal carotid artery (ICA) occlusion and vertebrobasilar insufficiency (VBI) with 52 patients with an ICA occlusion but without VBI. The patients with VBI significantly showed a weak collateral circulation and tight stenosis or occlusion of the contralateral ICA, suggesting that the mechanism responsible for the VBI was hemodynamic. Emboligenic factors ICA (stump, external carotid artery or common carotid artery ulcerated stenosis, ulcerated plaque on the contralateral ICA) dit not differ. Age, sex, vascular risk factors, vertebrobasilar or sub-clavian atheromatosis did not influence the development of VBI. We suggest that a hemodynamic phenomenon is the cause of VBI in our cases, probably from an intracranial steal from the vertebro-basilar circulation towards the carotid system.