The spectrum of carotid artery disease in asymptomatic patients.

A spectrum of asymptomatic patients with carotid bifurcation disease exists, with varying degrees of risk for each sub-group. With Duplex scanning we studied the carotid arteries of several asymptomatic populations: volunteers at a health fair, patients referred to our vascular laboratory because of cervical bruits or associated vascular disease, and the contralateral asymptomatic vessels in those patients who had previously undergone endarterectomy. Volunteers had an extremely low incidence of carotid disease, possibly reflecting a bias of more healthy individuals attending a health fair. The contralateral asymptomatic vessels and vessels in the hospital asymptomatic group both had similar disease, with mainly fibrous or calcific plaques. Occurrence of new carotid territory symptoms was low in each hospital group. However, there were more strokes in the territory of the contralateral asymptomatic vessels, suggesting a greater risk for these patients. Symptomatic vessels tend to have plaques that are heterogeneous and echolucent. Change in plaque morphology may eventually become the best predictor of stroke risk, but longer follow-up studies of plaque progression are needed. In the meantime, the characteristics of asymptomatic populations in carotid artery studies must be carefully defined.