Critical Appraisal of the Carotid Duplex Consensus Criteria in the Diagnosis of Carotid Artery Stenosis
What is the validity of the 2003 Society of Radiologists in Ultrasound consensus criteria for diagnosing carotid artery stenosis?
The authors compared the carotid duplex and angiography results of 376 carotid arteries in 197 patients. Receiver-operating characteristic (ROC) curves were used to compare peak systolic velocities (PSVs), end-diastolic velocities (EDVs) of the internal carotid artery (ICA), and ICA/common carotid (CCA) ratios in detecting <50%, 50-69%, and 70-99% stenosis of the ICA.
The consensus criteria for detection of 50-69% stenosis using a PSV of 125-230 cm/s had a sensitivity of 93%, specificity of 68%, and overall accuracy of 85%. The consensus defined cut-off of a PSV of >230 cm/s for defining a >70% stenosis had a sensitivity of 99%, specificity of 86%, and overall accuracy of 95%. Based on ROC, PSV (area under the curve [AUC] 0.97) was superior to EDV (AUC 0.94) or ICA/CCA ratio (AUC 0.84) in defining severity of stenosis. The addition of EDV or ICA/CCA ratio did not increase the accuracy of PSV in defining severity of stenosis. The accuracy of detecting 50-69% stenosis was increased by using an ICA PSV of 140-230 cm/s (instead of 125-230 cm/s), with a sensitivity of 94%, specificity of 92%, and overall accuracy of 92%.
The authors concluded that the consensus criteria can be accurately used for diagnosing ≥70% carotid artery stenosis.
Carotid duplex is the most commonly used diagnostic test for diagnosing carotid artery stenosis, and a number of patients will undergo carotid endarterectomy solely based on the results of this test. This study provides important validation of the consensus criteria and suggests that the use of these criteria may provide standardization across different laboratories, although such validation is probably best obtained from larger multicentric studies. Further, the accuracy of duplex while very high, is not 100%, and the duplex data must be considered in conjunction with patient symptoms and other comorbidities (e.g., low cardiac output, aortic stenosis, contralateral occlusion, etc.) that may impact the diagnostic accuracy of carotid duplex.
Keywords: Carotid Artery, Common, Diagnostic Tests, Routine, Endarterectomy, Carotid, Constriction, Pathologic, Carotid Stenosis, Carotid Artery, Internal, Cardiac Output, Low, Consensus
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