Abstract 20163: New Duplex-Ultrasound Velocity Criteria for Grading Internal Carotid Artery Stenosis
Choice of velocity criteria for grading internal carotid artery (ICA) stenosis (S) by Duplex-Ultrasonography (DUS) is of importance for therapeutic decision making. Established criteria are mostly not validated by new generation DUS-machines.
Aim: To establish optimal hemodynamic DUS-criteria for grading of ICA S based on multidetector computed tomographic angiography (MDCTA) in a prospective cohort analysis.
Patients and Methods: 148 carotid arteries of 81 patients (P) with wide spread S grades were studied with duplex US and MDCTA. P with contralateral occlusions and ipsilateral stenting were excluded. Raw data of all DUS and MDCTA images were prospectively acquired. Analysis was by CoreLab, 2 independent observers for each modality, blinded to the Results of the alternative method. MDCTA analysis was by TIANI software. Source data were used for multiplanar reformation (MPR) to measure diameters coaxial to the intra- and healthy poststenotic segment at loci according to the NASCET method. Accuracy of a subset of consecutive MDCTA measurements were validated by quantitative vascular analysis of biplane angiograms. DUS was performed by certified expert with a GE L9 System. DUS velocities were documented by certified readers independently. The degree of stenosis of MDCTA were categorized as 0–49, 50–69, or 70–99% and 100%. Receiver-operating-characteristic (ROC) curves were used to compare diagnostic criteria for 50 and 70% stenosis levels and to select threshold values that emphasize specificity as well as sensitivity.
Results: 148 carotid arteries were analysed. 10 occlusions were identified. Peak systolic velocity (PSV), internal/common carotid (ICR)- and mean intrastenotic/distal-ICA (MVR) systolic velocity ratio and end-diastolic velocity (EDV) were all shown to be good predictors of significant disease. ROC curves showed the optimum criteria for identifying 50% NASCET S at PSV 162 and EDV 62 cm/s, ICR 1.72, MVR 1.9, TAMEAN 55 cm/s and for 70% S at PSV 290 and EDV 101 cm/s, ICR 3,58, MVR 2.42, TAMEAN 73 cm/s.
Conclusion: optimal velocity criteria for moderate and severe ICA S can be recommended for DUS stenosis grading with equivalent equipment. Angle independent measurements show high sensitivity and spcificity at given cut-off points.
- © 2010 by American Heart Association, Inc.