Prognostic value and reproducibility of measurements of carotid stenosis. A comparison of three methods on 1001 angiograms. European Carotid Surgery Trialists' Collaborative Group.

Abstract

The use of three methods of measuring carotid stenosis, which produce different values on the same angiograms, has caused confusion and reduced the generalizability of the results of research. If the results of future studies are to be properly applied to clinical practice, and if noninvasive methods of imaging are to be properly validated against angiography, a single, standard method of measurement of stenosis on angiograms must be adopted. This standard method should be selected on the bases of its ability to predict risk of ipsilateral carotid distribution ischemic stroke and its reproducibility. The method of measurement of carotid stenosis used in the European Carotid Surgery Trial (ECST), that used in the North American Symptomatic Carotid Endarterectomy Trial (NASCET), and a method based on the measurement of the common carotid (CC) lumen diameter were studied. Their use in the prediction of ipsilateral carotid distribution ischemic stroke was assessed in 1001 consecutively selected patients randomly assigned to medical treatment in the ECST. Carotid stenosis was measured by two observers working independently, using all three methods, on the angiographic view that showed the most severe stenosis of the symptomatic carotid bifurcation. Interobserver agreement was determined, and 50 angiograms were remeasured to determine intraobserver agreement. There was little difference in the ability of the three methods to predict ipsilateral carotid distribution ischemic stroke. The CC method was consistently the most reproducible of the three, particularly for stenosis in the clinically important range of 50% to 90%. The CC method of measurement should be adopted as the standard method of measuring the degree of carotid stenosis on angiograms.

Accurate, practical and cost-effective assessment of carotid stenosis in the UK

“…3 Stenosis data given as ECST or common carotid (CCA) diameter methods 11,72 were converted to a NASCET stenosis using the equation: NASCET = (ECST -40)/0.6. 72 Note that the same equation also converts a CCA stenosis to NASCET. The NASCET method was chosen as the common standard, as this is a common method for calculating the percentage stenosis.…”

“…One of the US data points appears to be an outlier. 121 This study measured stenosis using the ECST method, 72 whereas the other papers all used the NASCET method. 93,104,120 There were too few data in the ROC plot for 50-69% stenosis to say whether the points lay on a curve or not ( Figure 14).…”

An integrated system for the complete segmentation of the common carotid artery bifurcation in ultrasound images

“…It causes thickening of the artery walls and may develop atherosclerotic carotid plaques that causes stenosis in the artery lumen, thus affecting the normal blood flow [1][2][3][4] . Atherosclerosis can result in heart attack and stroke [1][2][3]5] .…”

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Interobserver Agreement for 10% Categories of Angiographic Carotid Stenosis

“…The asymptomatic carotid artery was not visualized only when the symptomatic carotid artery appeared not to be stenosed at all or seemed occluded. Measurements of the degree of stenosis of the common and internal carotid arteries were made at its most severe site, according to the European Carotid Surgery Trial (ECST) method, 7 with the help of a small scale graduated in millimeters. A carotid stenosis of 40%, 70%, 80%, and 90% measured according to the ECST method would be rated on average 0%, 50%, 67%, and 84%, respectively, according to the North American Symptomatic Carotid Endarterectomy Trial criteria.…”