Pseudo- and segmental occlusion of the internal carotid artery: a new classification, surgical treatment and results.

OBJECTIVES: Occluded internal carotid arteries imply a high risk of ischaemic complications, but an "occluded" carotid artery is not always totally occluded. Pseudo- and segmental occlusions can be detected angiographically, and increasingly non-invasively, and include a variety of morphologic findings. METHODS AND MATERIALS: 128 patients with pseudo- or segmental occlusion were treated in a 13 year period. Three different types of pseudo- or segmental occlusion were identified. In most cases a subtotal stenosis (near-occlusion) at the carotid bifurcation is the underlying lesion (type I). In approximately 35% the internal carotid artery is totally occluded at the bifurcation, but collaterals prevent downstream occlusion (type II), or retrograde flow from the circle of Willis and ophthalmic artery preserves a patent petrous part and siphon (type III).
RESULTS: In 79% patency of the arteries could be restored. Three patients (2.3%) died perioperatively, nine (7%) developed ischaemic stroke (7 ipsilateral, 2 contralateral), one intracerebral haemorrhage. The combined stroke-mortality rate was 8.6%. During follow-up (41 +/- 29.9 months) four patients (4.5%) experienced a stroke (3 ipsilateral, 1 contralateral), one an intracranial (1.1%) haemorrhage and six transient ischaemic attacks (6.7%). The annual ipsilateral stroke rate was 0.9%, the cumulative patency rate of the entire series 78% after 73 months.
CONCLUSIONS: Although the surgical management carries an increased risk of complications (stroke, transient ischaemic attacks) compared to conventional carotid endarterectomy it is likely that the stroke risk can be reduced at least for symptomatic patients. Symptomatic internal carotid artery occlusion diagnosed non-invasively should be confirmed angiographically to exclude pseudo- or segmental occlusion.