Contents lists available at ScienceDirect Clinical Imaging journal homepage: www.elsevier.com/locate/clinimag Body Imaging Differential rates of progression of low-grade carotid stenosis detected by follow-up ultrasound: A single institution experience Edward Bluth a,b, ⁎ , Alaa Mohammed c , Daniel Fort c , Rhett Bouche b , Johnathon Collins b , Eboni G. Price-Haywood a,b,c a Ochsner Clinic Foundation, New Orleans, LA, USA b Ochsner Clinical School, University of Queensland, New Orleans, LA, USA c Ochsner Health System Center for Outcomes and Health Services Research, New Orleans, LA, USA ARTICLE INFO Keywords: Carotid artery stenosis Doppler ultrasound imaging Preventive health service Low-grade stenosis Follow-up low-grade stenosis Noncritical carotid stenosis ABSTRACT Objectives: The growing body of evidence suggesting that lifestyle changes and aggressive medical management reduce the risk of strokes in patients with carotid stenosis has fostered interest in noninvasive screening. The objective of this study was to develop recommendations for follow-up carotid ultrasound surveillance of patients with < 60% carotid stenosis. Methods: This retrospective observational cohort study includes 2956 patients seen between August 1998 and March 2015 in 4440 visits. Data analysis was restricted to 7710 carotid ultrasounds. Primary outcome was progression of carotid stenosis as defined by the “bulb” method: baseline stenosis of 0%–39% progressed to 40%–59% on subsequent examination, baseline stenosis of 0%–39% progressed to ≥60%, or baseline of 40%–59% progressed to ≥60%. Progression was estimated using Cox proportional hazard ratios and the Kaplan- Meier method. Results: More than 10% of patients progressed in the 40%–59% baseline group within 12 months compared to 78 months for the 0%–39% baseline group. Patients who progressed had a higher proportion of peripheral vascular disease, and current/former smoking compared to those who did not. While there were statistically significant correlations between medication classes and comorbidities, none of the medications studied appeared to slow carotid stenosis progression. Conclusions: In our experience, for patients with a 0%–39% carotid stenosis, follow-up examination should be performed at 6-year intervals. For patients with 40%–59% carotid stenosis, follow-up should be obtained an- nually to identify those who progress to a level requiring intervention. Future studies should examine whether study findings can be replicated using other approaches for determining carotid stenosis. 1. Introduction Stroke is the second most common cause of mortality worldwide [1,2]. In 2013, there was an estimate of 10.3 million new strokes globally, with cerebrovascular disease accounting for 8 million deaths [2]. Stroke is also the third most common cause of disability [2–4]. As the prevalence of diabetes and cardiovascular disease in younger adults continues to grow, the stroke burden will continue to shift toward younger populations unless effective preventive strategies are im- plemented [2]. One such strategy is screening individuals for carotid bifurcation disease via carotid duplex scans [5,6]. A number of previously reported outcome-based studies using car- otid duplex examinations have made recommendations for carotid stenosis cutoff grades in which surgical intervention is preferable to conservative medical therapy for stenosis greater than 50%, 60%, or 70%, depending on the study. Although there is controversy about which is the most critical level for intervention, these papers have generally made no recommendations for how to follow patients who have a grade of stenosis below what is recommended for intervention [4,7–10]. Part of the reason for the lack of recommendations for following patients with low-grade stenosis is that the role of duplex scans in early https://doi.org/10.1016/j.clinimag.2020.06.048 Received 3 April 2020; Received in revised form 27 June 2020; Accepted 29 June 2020 Abbreviations: AAA, abdominal aortic aneurysm; BMI, body mass index; DM, diabetes mellitus; HLD, hyperlipidemia; HR, hazard ratio; HTN, hypertension; IHD, ischemic heart disease; PVD, peripheral vascular disease; TIA, transient ischemic attack; USPSTF, US Preventive Services Task Force ⁎ Corresponding author at: Department of Radiology, Ochsner Clinic Foundation, 1514 Jefferson Hwy., New Orleans, LA 70121, USA. E-mail addresses: ebluth@ochsner.org (E. Bluth), alaa.mohammed@ochsner.org (A. Mohammed), daniel.fort@ochsner.org (D. Fort), eboni.pricehaywood@ochsner.org (E.G. Price-Haywood). Clinical Imaging 67 (2020) 170–176 0899-7071/ © 2020 Elsevier Inc. All rights reserved. T