This Article Full Text Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wilterdink, J. L. Articles by Ward, R. Search for Related Content PubMed PubMed Citation Articles by Wilterdink, J. L. Articles by Ward, R.

(Stroke. 1996;27:1094-1098.)
© 1996 American Heart Association, Inc.

Articles

Performance of Carotid Ultrasound in Evaluating Candidates for Carotid Endarterectomy Is Optimized by an Approach Based on Clinical Outcome Rather Than Accuracy

Janet L. Wilterdink, MD; Edward Feldmann, MD; J. Donald Easton, MD Richard Ward, MD

From the Department of Clinical Neurosciences, Brown University School of Medicine and Rhode Island Hospital, Providence, RI (J.L.W., E.F., J.D.E.), and the Center for Clinical Effectiveness, Henry Ford Health Sciences Center, Case Western Reserve University, Detroit, Mich (R.W.).

Correspondence to Janet L. Wilterdink, MD, Department of Clinical Neurosciences, Brown University School of Medicine and Rhode Island Hospital, 110 Lockwood St, Suite 324, Providence, RI 02903. E-mail wilterdink@brown.edu.

Background and Purpose The best method of selecting endarterectomy candidates for cerebral angiography is controversial. Carotid duplex ultrasound (CDUS) is widely used, but its performance varies across institutions. The clinical utility of CDUS could be improved with test criteria based on patient outcome rather than test accuracy.

Methods In 155 carotid bifurcations studied by CDUS and cerebral angiography, the degree of angiographic stenosis was measured by a reader, blinded to CDUS, using the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method. We calculated accuracy, sensitivity, and specificity for predicting 70% angiographic carotid stenosis of different peak systolic frequencies (PSF) measured by CDUS and generated a receiver operator characteristic (ROC) curve. We used NASCET outcome data and published data on angiographic complications to define relative "costs" of false-positive and false-negative CDUS, and we determined the point on the ROC curve representing the CDUS criterion with the highest clinical utility. We compared projected morbidity and mortality rates for 1000 hypothetical endarterectomy candidates resulting from the use of the most accurate CDUS criterion versus the CDUS criterion with the highest clinical utility by ROC analysis.

Results While PSF 8 kHz had the highest CDUS accuracy (93%), its projected stroke and death rate due to CDUS error was 10.4/1000. On the other hand, PSF 7 kHz, defined by ROC analysis to have the highest clinical utility, had a lower morbidity and mortality rate of 6.8/1000.

Conclusions The use of ROC analysis and available outcome data can improve the performance of CDUS in selecting endarterectomy candidates for cerebral angiography.

Key Words: angiography • carotid endarterectomy • carotid stenosis • diagnosis • outcome • ultrasonics

This article has been cited by other articles:

				E. Feldmann, J. L. Wilterdink, A. Kosinski, M. Lynn, M. I. Chimowitz, J. Sarafin, H. H. Smith, F. Nichols, J. Rogg, H. J. Cloft, et al. The Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) Trial Neurology, June 12, 2007; 68(24): 2099 - 2106. [Abstract] [Full Text] [PDF]

				M. H. Heijenbrok-Kal, E. Buskens, P. J. Nederkoorn, Y. van der Graaf, and M. G. M. Hunink Optimal Peak Systolic Velocity Threshold at Duplex US for Determining the Need for Carotid Endarterectomy: A Decision Analytic Approach Radiology, December 21, 2005; (2005) 2381041078. [Abstract] [Full Text]

				G. Melissano, R. Castellano, R. Zucca, and R. Chiesa Results of Carotid Endarterectomy Performed with Preoperative Duplex Ultrasound Assessment Alone Vascular and Endovascular Surgery, March 1, 2001; 35(2): 95 - 101. [Abstract] [PDF]

				E. G. Grant, A. J. Duerinckx, S. M. El Saden, M. L. Melany, G. M. Hathout, P. T. Zimmerman, A. K. Marumoto, S. N. Cohen, and J. D. Baker Ability to Use Duplex US to Quantify Internal Carotid Arterial Stenoses: Fact or Fiction?1 Radiology, January 1, 2000; 214(1): 247 - 252. [Abstract] [Full Text]

				O. E. H. Elgersma, M. van Leersum, P. C. Buijs, M. S. van Leeuwen, Y. T. van de Schouw, B. C. Eikelboom, and Y. van der Graaf Changes Over Time in Optimal Duplex Threshold for the Identification of Patients Eligible for Carotid Endarterectomy Stroke, November 1, 1998; 29(11): 2352 - 2356. [Abstract] [Full Text] [PDF]

				J.L. Wilterdink, E. Feldmann, K.L. Furie, M. Bragoni, and J.G. Benavides Transcranial Doppler Ultrasound Battery Reliably Identifies Severe Internal Carotid Artery Stenosis Stroke, January 1, 1997; 28(1): 133 - 136. [Abstract] [Full Text]