Background: Progressively worsening severity of internal carotid artery (ICA) stenosis has been used as an indication for carotid revascularization in asymptomatic patients.

Methods: We analyzed data from 5,888 Cardiovascular Health Study participants aged ≥65 years who underwent serial carotid Doppler ultrasound (at baseline and 5 year follow-up). The severity was classified into four grades by a central reader: 0-24%, 25-49%, 50-69%, 70-99%, and complete occlusion. Progressively worsening severity of ICA stenosis was defined if the severity of ICA with the highest velocity at baseline evaluation had increased by one grade or greater at 5 year follow-up. Hazards ratio for cardiovascular events during follow-up were estimated using Cox proportional Hazards analysis.

Results: The rate of ipsilateral ischemic stroke was similar among patients with and without progressively worsening severity of ICA stenosis over a mean follow-up period (mean ±SD) of 7.3 ± 1 years. The risk of any ischemic stroke was (HR 1.3, 95% confidence interval [CI] 1.0-1.6) but not ipsilateral ischemic stroke (HR 1.4, 95% CI 0.6 – 3.1) was statistically higher among patients with progressively worsening severity of ICA stenosis after adjusting for age, race, serum cholesterol, diabetes mellitus, blood pressure and cigarette smoking. The risk of myocardial infarction (HR 1.3, 95% CI 1.1-1.7) was significantly higher among patients with progressively worsening severity of ICA stenosis.

Conclusions: Patients with progressively worsening severity of ICA stenosis appear to be at higher risk of  cardiovascular events but not ipsilateral cerebral ischemic symptoms.

Is Progressively Worsening Severity of Internal Carotid Artery Stenosis by Carotid Doppler Ultrasound in Asymptomatic Patients a Risk Factor for Ischemic Stroke?