Vertebrobasilar transient ischemic attacks in internal carotid artery occlusion or tight stenosis
J. Bogousslavsky and F. Regli
We studied 12 patients with internal carotid artery (ICA) occlusion or
tight stenosis but without vertebrobasilar and subclavian atherosclerosis
who suffered vertebrobasilar insufficiency (VBI). The patients with ICA
occlusion were compared with a sex- and age-matched control group that had
ICA occlusion but no VBI. Visible infarct on computed tomographic scan,
greater size of visible infarct, weak collateral circulation, and bilateral
atherosclerosis of the ICA significantly correlated with the occurrence of
VBI. No significant difference was demonstrated for emboligenic lesions,
but posterior to anterior flow through the posterior communicating arteries
was demonstrated only in the patients with VBI. These facts suggested
hemodynamic disturbances with "steal VBI." In ICA tight stenosis, VBI
symptoms disappeared after endarterectomy but persisted in patients with
more than 50% stenosis; this was also suggestive of hemodynamic VBI.
Vertebrobasilar insufficiency had a prognostic significance, being
associated with an increased occurrence of delayed stroke.
