[Mechanisms of cerebral ischemia following occlusion of the carotid artery].

During a follow-up study (40 months) of 80 patients with proven uni- or bilateral occlusion of internal carotid artery (ICA), delayed cerebroretinal ischemic events occurred in 46% of the cases (distal to the occluded ICA in 40%). Ischemia in the area ipsilateral to the ICA occlusion most often corresponded to microemboli following the external carotid collateral pathways, less often to hemodynamic hypoperfusion, and exceptionally to microemboli from stenosis of the contralateral ICA or of the vertebrobasilar system. Ischemia in the contralateral ICA area was due to microemboli from stenosis of the corresponding ICA. Vertebrobasilar ischemia was usually hemodynamic, and foreshadowed a poor outcome. A variety of medical or surgical treatments may be indicated according to the mechanisms of these delayed episodes.