Study objective: To appraise critically the clinical indications for diagnostic evaluation of carotid artery disease and the efficacy, safety, limitations, and relative costs of commonly used noninvasive diagnostic tests.
Design: Formal decision analysis to determine the relative value of several diagnostic strategies and information synthesis of studies evaluating noninvasive diagnostic tests.
Setting: We did a secondary analysis of the literature, using available data to generate estimates for the probability of selected, clinically important events and the utilities of relevant outcomes observed in patients when carotid artery disease is present or absent, and we critically appraised studies reported since 1980 to estimate the sensitivity and specificity, safety, limitations, and costs of diagnostic tests.
Main results: For patients with asymptomatic neck bruits who are and who are not being considered as candidates for other vascular surgery, no diagnostic testing is recommended. For symptomatic patients with anterior-circulation transient ischemic attacks or previous minor strokes, noninvasive diagnostic testing is recommended if surgical treatment is being considered. Patients who previously had minor strokes could be directly referred for selective carotid angiography because they have a higher likelihood of a surgically approachable carotid lesion. Patients with nonlateralizing signs and symptoms of ischemia do not need diagnostic evaluation of possible carotid artery disease unless their symptoms are related to ischemia in the carotid artery circulation. The preferred noninvasive diagnostic test is duplex ultrasound, which has a sensitivity of approximately 85% and a specificity of 90%. If duplex ultrasound is not available, an alternative noninvasive test is carotid Doppler ultrasound.
Conclusions: We recommend a conservative diagnostic approach in patients with suspected carotid artery disease. Noninvasive diagnostic testing is indicated only for symptomatic patients with transient ischemic attacks in the anterior circulation who are considered candidates for carotid endarterectomy, when knowledge of the vessel anatomy is necessary.