The significance of one occluded internal carotid artery.

One-third of patients who develop internal carotid occlusion will die or have disabling cerebral symptoms. ~ The results of urgent carotid thromboendarterectomy in patients with established internal carotid occlusion were disappointing. Extracranial to intracranial bypass in symptomatic patients with internal carotid artery occlusion produced high numbers of strokes and was not of benefit. 2 Attention turned to the prevention of internal carotid occlusion rather than cerebral revascularisation. Miller, a Canadian neurologist, noted that some patients experienced transient ischaemic attacks as a warning of impending internal carotid occlusion. 3 He suggested that surgical intervention to the internal carotid artery would prevent stroke. Recently the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST) demonstrated that patients with a symptomatic internal carotid stenosis >70% who had carotid endarterectomy were significantly less likely to develop a stroke than patients on best medical treatment. 4'5 The ability of surgeons to prevent stroke and death by carotid endarterectomy depends on the balance between the variable risks of internal carotid disease and of carotid endarterectomy. The greater the risk of disease and the lower the risk of surgery, the more efficacious carotid endarterectomy becomes. Significantly higher morbidity and mortality rates for carotid endarterectomy have been found in women, the elderly (age >75 years), and patients with internal carotid occlusion. 6 Does this mean that patients with internal carotid occlusion should not undergo carotid endarterectomy? The answer to this question is likely to be different for symptomatic and asymptomatic patients.