Internal carotid artery stenosis: rate of progression

Abstract

Objectives: to assess the incidence and the rate of progression of internal carotid artery (ICA) stenosis and to determine the related risk factors.

Design: open prospective study.

Materials and methods: between 1988-1997, 442 carotid arteries with various degrees of stenosis were followed using colour duplex ultrasonography every 6 months. Of these arteries, 290 (66%) were asymptomatic, 62 (14%) had caused transient ischaemic attack and 90 (20%) a stroke. In 145 cases (33%), there was concomitant coronary artery disease (CAD), in 134 (30%) diabetes mellitus, in 248 (56%) hypertension, in 139 (31%) hypercholesterolaemia and in 370 (84%) history of smoking. Of the plaques, 44 (10%) were uniformly echolucent, 19 (4%) haemorrhagic, 136 (31%) predominantly echolucent, 146 (33%) predominantly echogenic and 97 (22%) uniformly echogenic.

Results: significant progression of stenosis occurred in 82 cases (19%). The mean progression rate in these cases was 15% annually (range: 5-50%). There was no statistically significant correlation between the progression of the ICA stenosis and initial neurological status, age, gender, diabetes mellitus, hypertension, hypercholesterolaemia and smoking habit. Stenosis progression was correlated only with CAD and the ultrasonographic characteristics of the plaques. Patients with CAD as well as those with uniformly echolucent plaques presented a higher incidence and rate of stenosis progression (p<0.05).

Conclusions: progression of internal carotid artery stenosis occurred in 19% of cases. The mean progression rate in these patients was 15% annually and was correlated with CAD and the ultrasonographic characteristics of the plaque.