Progression Rate and Ipsilateral Neurological Events in Asymptomatic Carotid Stenosis

Abstract

Progression of asymptomatic carotid stenoses with >50% luminal narrowing is associated with an increased risk of stroke. The significance of the progression rate in these patients is unknown. The main aim of this study was to evaluate the rate of change of carotid luminal narrowing over 1 year, as a risk factor for ipsilateral ischemic events, in patients with a >50% asymptomatic carotid stenosis. Secondary aims were to establish the incidence of changes in carotid luminal narrowing and establish additional risk factors for ipsilateral neurological events. A retrospective analysis was conducted of data derived from the deferred endarterectomy arm of the Asymptomatic Carotid Surgery Trial. Patients were followed up for ≥5 years with serial carotid duplex examinations. Data were derived from information obtained at randomization and annual follow-up visits with carotid duplex examination. Potential risk factors for ipsilateral neurological events were analyzed in Poisson regression models. Data from 1469 patients were included. Two hundred forty-four had ipsilateral events; 240 had ipsilateral carotid surgery; 370 died from nonstroke causes; and 82 had an asymptomatic carotid occlusion. The annual incidence of progression in the cohort as a whole was 5.2%. Ipsilateral events occurred in 17% of patients. Diabetes and previous contralateral symptoms showed a significant independent association with ipsilateral neurological events. Ipsilateral events were associated with high rates of progression over 1 year but not with low progression rates or regression. Fast rates of progression of carotid luminal narrowing should be interpreted as a sign of significantly increased risk of future ipsilateral neurological events.