Objectives: The purpose of this study was to determine the incidences and rates of progression of varying degrees of carotid stenosis that do not require intervention according to the Asymptomatic Carotid Atherosclerosis Study, the European Carotid Surgery Trial, and the North American Symptomatic Carotid Endarterectomy Trial, and from this information, to provide evidence-based recommendations for follow-up imaging.
Methods: A retrospective review was performed of all carotid ultrasound examinations performed at a single institution from January 1995 through April 2015. Examinations following endarterectomy or stenting were excluded. Stenoses were classified by a modification of the criteria of Bluth et al (Radiographics 1988; 8:487-506). A Kaplan-Meier survival analysis was performed for stenosis progression and to provide information for follow-up recommendations.
Results: Most of the carotid arteries (91.6%) reviewed for this study showed 1% to 39% stenosis. However, only 6.8% of carotid arteries with 1% to 39% stenosis progressed compared to 38.9% of carotid arteries with 40% to 59% stenosis. A table of evidence-based follow-up recommendations is provided for patients with varying levels of stenosis.
Conclusions: We provide evidence-based follow-up recommendations for patients who have low degrees of carotid stenosis. Different degrees of carotid stenosis progress at different rates and therefore should be followed at different intervals. Additionally, the most patients in our database showed 1% to 39% stenosis and did not have any follow-up imaging, suggesting that carotid ultrasound may not be overused for low degrees of stenosis.
Keywords: carotid artery diseases; carotid stenosis; carotids/extracranial; diagnostic imaging; flow-limiting stenosis; follow-up studies; stroke; ultrasound.
© 2017 by the American Institute of Ultrasound in Medicine.