Measuring carotid stenosis: Time for a reappraisal

Abstract

Background and Purpose: Data from recent multicenter carotid endarterectomy trials have questioned the validity and reliability of Doppler ultrasound in the assessment of carotid stenosis. Methods: We prospectively analyzed 45 patients undergoing carotid angiography to compare the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) methods of measuring carotid stenosis with those of direct visualization (“eyeballing”) and duplex ultrasound. Linear NASCET and ECST measurements were also converted into area using the πr2function and termed “squared NASCET” (N2) and “squared ECST” (E2). In 15 of 45 patients undergoing carotid endarterectomy, the carotid plaque was removed intact, sectioned, and photographed for computer measurement of cross-sectional area. Comparison of this “gold standard” was then made to each method of measurement. Results: Comparison between duplex and the various angiographic measurement techniques revealed significant differences between NASCET and duplex (P