New information on the value of plaque characterisation--relation to symptoms.

This paper reviews the literature on the significance of carotid plaque echomorphology and degree of stenosis in relation to the different types of cerebrovascular symptomatology (amaurosis fugax, hemispheric transient ischaemic attacks, stroke) and the asymptomatic status. It provides evidence that amaurosis fugax is associated with hypoechoic and severely stenosed plaques, the hemispheric transient ischaemic attacks and stroke are associated with plaques of intermediate echodensity and stenosis while the asymptomatic status is associated with hyperechoic and moderately stenosed plaque. It lends support to the notion that plaque hypoechoicity is associated with embologenicity. It supports the view that the severe carotid stenosis facilitates the opening of the cerebral collateral circulation and that amaurosis fugax is associated with an "opened" cerebral collateral supply as contrasted to the cerebrovascular symptomatology. It proposes the inclusion of the cerebral collateral circulation as a stroke risk factor along with the plaque echomorphology and the degree of stenosis in the natural history studies of asymptomatic individuals with carotid bifurcation plaques.