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Computed tomography angiography-derived area stenosis calculations overestimate degree of carotid stenosis compared with North American Symptomatic Carotid Endarterectomy Trial-derived diameter stenosis calculations.

Authors
  • Arous, Edward J1
  • Judelson, Dejah R2
  • Agrawal, Anushree3
  • Dundamadappa, Sathish K3
  • Crawford, Allison S2
  • Malka, Kimberly T4
  • Simons, Jessica P2
  • Schanzer, Andres2
  • 1 Division of Vascular and Endovascular Surgery, University of Massachusetts Medical School, Worcester, Mass. Electronic address: [email protected]
  • 2 Division of Vascular and Endovascular Surgery, University of Massachusetts Medical School, Worcester, Mass.
  • 3 Department of Radiology, University of Massachusetts Medical School, Worcester, Mass.
  • 4 Division of Vascular Surgery, Maine Medical Center, Portland, Me.
Type
Published Article
Journal
Journal of vascular surgery
Publication Date
Aug 01, 2021
Volume
74
Issue
2
Identifiers
DOI: 10.1016/j.jvs.2020.12.085
PMID: 33548432
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

The degree of carotid artery stenosis, calculated using catheter-based angiography and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method, has been shown to predict the stroke risk in several, large, randomized controlled trials. In the present era, patients have been increasingly evaluated using computed tomography (CT) angiography (CTA) before carotid artery revascularization, especially as the use of transcarotid artery revascularization has increased. Interpretation of CTA findings regarding the degree of carotid stenosis has not been standardized, with both NASCET methods and the area stenosis used. We performed a single-institution, blinded, retrospective analysis of CTA studies using both the NASCET method and the CT-derived area stenosis to assess the concordance and discordance between the two methods when evaluating ≥70% and ≥80% stenosis. The UMass Memorial Medical Center vascular laboratory database was queried for all carotid duplex ultrasound scans performed from 2008 to 2017. The included patients were limited to those with duplex-defined ≥70% stenosis (defined as a peak systolic velocity of ≥125 cm/s and an internal carotid artery/common carotid artery ratio of ≥4), and a correlative CTA study performed within 1 year of the duplex ultrasound examination. A blinded review of all correlative CTA studies using centerline measurements on a three-dimensional workstation (Aquarius iNtuition Viewer; Terarecon, Durham, NC) was performed to characterize the degree of carotid stenosis using the NASCET method and the area stenosis method. Patients were excluded if revascularization had been performed between the two imaging studies. Of the 37,204 carotid duplex ultrasound scans reviewed (performed from 2008 to 2017), 3480 arteries met the criteria for duplex ultrasound-defined ≥70% stenosis. A correlative CTA study within 1 year of the duplex ultrasound examination was identified in 460 arteries, of which 320 were adequate quality for blinded review. The median interval between the duplex ultrasound and CTA examinations was 9.5 days. Concordance between the area stenosis and NASCET methods was poor for both ≥70% (κ = 0.32) and ≥80% (κ = 0.25) stenosis. Of the 247 arteries considered to have ≥70% area stenosis, 127 (51.4%) were considered to have ≥70% stenosis using the NASCET method. Of the 169 arteries considered to have ≥80% area stenosis, 44 (26.0%) were considered to have ≥80% stenosis using the NASCET method. The area stenosis CTA calculations of carotid artery stenosis dramatically overestimated the degree of carotid stenosis compared with that calculated using the NASCET method. Given that stroke risk estimates have been determined from trials that used the NASCET method, the area stenosis method likely overestimates the risk of stroke. Therefore, area stenosis calculations could lead to unnecessary carotid revascularization procedures. This model highlights the need for standardized usage of the NASCET method when using CTA as the imaging modality to determine the threshold for carotid revascularization. Copyright © 2021 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

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