The natural history of asymptomatic carotid bifurcation plaques.

Seventy-three patients with an angiographically identified asymptomatic stenosis (greater than 50%) and/or ulceration of the common carotid bifurcation have been followed from 6 months to 10 years (average 4 years). All patients had previously undergone contralateral carotid endarterectomy for a transient ischemic attack (TIA) or minor stroke in that carotid territory. During follow-up, 22 patients (30%) developed new symptoms of cerebral ischemia. Twelve developed ischemia referable to the previously asymptomatic side (10 TIA's, 2 strokes). Six developed recurrent ischemic symptoms in the territory of the previously symptomatic and operated carotid artery (2 TIA's, 4 strokes). Five developed ischemia in the vertebro-basilar territory (2 TIA's, 3 strokes). Thirteen patients (17%) died during follow-up, including 6 from cardiovascular disease and 3 from stroke. In our series the incidence of stroke in the territory of a significant asymptomatic carotid plaque was low (3%). Patients were as likely to develop stroke in the territory of a previously operated carotid artery (5%) with asymptomatic carotid lesions is to keep them under review and to consider endarterectomy only if appropriate ischemic symptoms (which are most likely to be TIA's) develop.