Atheromatous pseudo-occlusion of the internal carotid artery.

In the past year, three patients were referred for microvascular bypass surgery for relief of symptoms secondary to an apparently occluded internal carotid artery (ICA). Careful review of the late films of their initial arteriographic series or repeat arteriography with a specialized technique revealed a thin trickle of contrast medium flowing antegrade through a region of extreme stenosis. This thin line of contrast material ascended slowly to meet the column of contrast medium in the cavernous carotid segment that was filling by collateral circulation. Surgical exploration of the neck in these patients revealed a patent but collapsed ICA distal to a localized atheromatous plaque. These patients have been asymptomatic following carotid endarterectomy. This distinctive angiographic appearance may be described as "atheromatous pseudo-occlusion." Once recognized, carotid endarterectomy is the logical treatment of choice.