Grading of internal carotid artery stenosis: Validation of Doppler/duplex ultrasound criteria and angiography against endarterectomy specimen

Objectives: duplex ultrasound has replaced angiography prior to carotid end arterectomy (CEA) in many institutions. However, the indications for CEA ar e based on angiographically controlled studies and widely accepted ultrasou nd criteria do not exist. Consequently the reliability of Doppler and/or du plex ultrasound to predict a high-grade ICA stenosis has to be proven. Design: prospective validation study. Materials: one hundred and fifty carotid bifurcations assessed by ultrasoun d and selective angiography and 68 acrylat outcasts of carotid specimen aft er eversion CEA. Methods: ICA stenosis was measured angiographically according to the ECST c riteria. Combined Doppler acoustic standard criteria (CDASC), peak systolic frequency (PSF), peak systolic velocity (PSV) and end-diastolic velocity ( EDV) served as criteria for the ultrasound assessment. These criteria and t he results of angiography were compared to the degree of ICA stenosis deter mined by specimen measurements. Results: the median degree of ICA stenosis as assessed by angiography (82%, range 56-97%) and CDASC (83%, range 50-99%) corresponded well to the speci men measurements (80%, range 50-95%). The sensitivity of angiography and CD ASC to predict a 70-90% ICA stenosis (ECST criteria) compared to the specim en measurements was 88% and 95%, respectively. The positive predictive valu e (PPV) reached 92% and 96%, respectively. CDSCA were equivalent to angiogr aphy and were superior to the best single frequency or velocity parameters. If CDASC do not indicate a greater than or equal to 70% ICA stenosis in sp ite of a PSV greater than or equal to 180 cm/s and/or an EDV greater than o r equal to 50 cm/s, angiography may detect patients with a > 70% ICA stenos is. Conclusions: CDASC are valid in the quantification of high-grade ICA stenos is. They are more reliable than single velocity and/or frequency measuremen ts. However, if velocity criteria and CDASC do not agree, angiography shoul d be performed.