title: Institutional differences in carotid artery duplex diagnostic criteria result in significant variability in classification of carotid artery stenoses and likely lead to disparities in care.
abstract: BACKGROUND
  The indications for carotid revascularization are based almost exclusively on the results of carotid duplex ultrasonography. Noninvasive vascular laboratories show large variation in the diagnostic criteria used to classify degree of carotid artery stenosis. We hypothesize that variability of these diagnostic criteria causes significant variation in stenosis classification directly affecting the number of revascularizations and associated costs.
  
  
  RESULTS
  The diagnostic criteria to interpret carotid duplex ultrasounds were obtained from 10 New England institutions. All carotid duplex scans performed at our institution were reviewed from 2008 to 2012. Using the diagnostic criteria from each institution, the degree of stenosis that would have been reported was classified as 70% to 99% asymptomatic, 80% to 99% asymptomatic, and 50% to 99% symptomatic. We then calculated the theoretical number of carotid revascularization procedures that this cohort would be offered using each institution's diagnostic criteria and the costs of these procedures based on reimbursement rates. Among 10 614 patients who underwent 15 534 carotid duplex scans, 31 025 arteries were reviewed. Application of the 10 institutions' criteria to the patients from our institution yielded marked variation in the number classified as 70% to 99% asymptomatic (range, 186-2201), 80% to 99% asymptomatic (range, 78-426), and 50% to 99% symptomatic (range, 157-781). If revascularizations were based on these results, costs would range from $2.2 to $26 million, $0.9 to $5.0 million, and $1.9 to $9.2 million, respectively.
  
  
  CONCLUSIONS
  Differences in diagnostic criteria to interpret carotid ultrasound result in significant variation in classification of carotid artery stenosis, likely leading to differences in the number and subsequent costs of revascularizations. This theoretical model highlights the need for standardization of carotid duplex criteria.
authors.affiliation: From the Department of Surgery, University of Massachusetts Medical School, Worcester, MA (Edward J. Arous, W.P.R., F.A.A., Elias J. Arous, L.M.M., A.S.); Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA (D.T.B.); and Department of Surgery, Brigham and Women's Hospital, Boston, MA (N.D.H.).
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Arous
authors.affiliation: From the Department of Surgery, University of Massachusetts Medical School, Worcester, MA (Edward J. Arous, W.P.R., F.A.A., Elias J. Arous, L.M.M., A.S.); Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA (D.T.B.); and Department of Surgery, Brigham and Women's Hospital, Boston, MA (N.D.H.).
authors.forename: Donald T
authors.initials: DT
authors.lastname: Baril
authors.affiliation: From the Department of Surgery, University of Massachusetts Medical School, Worcester, MA (Edward J. Arous, W.P.R., F.A.A., Elias J. Arous, L.M.M., A.S.); Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA (D.T.B.); and Department of Surgery, Brigham and Women's Hospital, Boston, MA (N.D.H.).
authors.forename: William P
authors.initials: WP
authors.lastname: Robinson
authors.affiliation: From the Department of Surgery, University of Massachusetts Medical School, Worcester, MA (Edward J. Arous, W.P.R., F.A.A., Elias J. Arous, L.M.M., A.S.); Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA (D.T.B.); and Department of Surgery, Brigham and Women's Hospital, Boston, MA (N.D.H.).
authors.forename: Francesco A
authors.initials: FA
authors.lastname: Aiello
authors.affiliation: From the Department of Surgery, University of Massachusetts Medical School, Worcester, MA (Edward J. Arous, W.P.R., F.A.A., Elias J. Arous, L.M.M., A.S.); Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA (D.T.B.); and Department of Surgery, Brigham and Women's Hospital, Boston, MA (N.D.H.).
authors.forename: Nathanael D
authors.initials: ND
authors.lastname: Hevelone
authors.affiliation: From the Department of Surgery, University of Massachusetts Medical School, Worcester, MA (Edward J. Arous, W.P.R., F.A.A., Elias J. Arous, L.M.M., A.S.); Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA (D.T.B.); and Department of Surgery, Brigham and Women's Hospital, Boston, MA (N.D.H.).
authors.forename: Elias J
authors.initials: EJ
authors.lastname: Arous
authors.affiliation: From the Department of Surgery, University of Massachusetts Medical School, Worcester, MA (Edward J. Arous, W.P.R., F.A.A., Elias J. Arous, L.M.M., A.S.); Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA (D.T.B.); and Department of Surgery, Brigham and Women's Hospital, Boston, MA (N.D.H.).
authors.forename: Louis M
authors.initials: LM
authors.lastname: Messina
authors.affiliation: From the Department of Surgery, University of Massachusetts Medical School, Worcester, MA (Edward J. Arous, W.P.R., F.A.A., Elias J. Arous, L.M.M., A.S.); Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA (D.T.B.); and Department of Surgery, Brigham and Women's Hospital, Boston, MA (N.D.H.). andres.schanzer@umassmemorial.org.
authors.forename: Andres
authors.initials: A
authors.lastname: Schanzer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000191:economics / Q000601:surgery; D018450:Disease Progression; D005260:Female; D017048:Health Care Costs; D054625:Healthcare Disparities; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization; D009511:New England; D018579:Patient Selection; D018616:Ultrasonography, Doppler, Duplex
keywords: carotid arteries; carotid stenosis; endarterectomy, carotid