Carotid plaque morphology and cerebrovascular events

Beside the degree of stenosis, plaque morphology obtained by the B mode ultrasound technique has been considered to define the plaque at risk for cerebrovascular events, and a subset of patients who deserve more strict surveillance. Our aim was to evaluate the relationship between plaque morphology, progression of stenosis, and the development of new cerebrovascular events.

We followed up by carotid duplex scan 230 asymptomatic patients, evaluating the degree and progression of internal carotid (ICA) stenoses and plaque morphology of the atherosclerotic lesions.

During the follow-up period (median 32 month, range 6-125 months) 7% of patients developed ischemic neurological events of which 1.7% was a stroke. Of these events, only 5.7% correlated with carotid lesions. The new neurological events correlated with the degree and progression of stenoses, with a non homogeneous echographic appearance and irregular surface. The progression of the degree of stenoses was the parameter that correlated the most with the development of new neurologic symptoms. Nevertheless, the lesions that progressed modified their echographic pattern from homogeneous to non homogeneous in 78% of cases. Irregular surface and high degree of stenoses more than the baseline echographic pattern seem to correlate with plaque progression.

Our follow-up study confirmed that ICA stenosis is a benign condition: very few strokes clearly correlated to the stenosis were observed. Nevertheless, the major predictors of risk for cerebrovascular events, besides the degree of stenoses, are the progression of the degree of stenosis, irregular surface and non-homogeneous echographic appearance.