DUPLEX CRITERIA for GRADING of EXTRACAROTID STENOSIS

Objectives External carotid artery (ECA) stenosis is an independent mortality predictor. Additionally, concomitant ECA and internal carotid artery (ICA) stenoses progression has been associated with an increased risk of ipsilateral ischemic events in asymptomatic patients. Universally accepted ECA duplex velocity criteria, for the prediction of stenosis, do not exist. Methods Consecutive patients undergoing angiography and carotid duplex assessments were compared (n=140). ICA, common carotid artery (CCA) and ECA peak systolic velocities (PSV) were recorded. ECA/CCA PSV ratio was calculated. These parameters were compared with angiographic ECA measurements. Receiver-operator curve (ROC) analysis were used to determine optimal criteria in identifying ECA stenosis of >50%. Results In patients with little ipsilateral ICA disease, for the detection of ECA stenosis of > 50%, an ECA PSV >148 cm/s provided sensitivity 80%, specificity 76.2%, and an overall accuracy of 77.1%. An ECA/CCA PSV ratio of 1.45 demonstrated sensitivity 73.7%, specificity 66.7%, and an accuracy 68.2%. In patients with ICA stenosis > 50%, for the detection of ECA stenosis of > 50%, an ECA PSV >179 cm/s provided sensitivity 50%, specificity 79.6%, and overall accuracy 71.3%. An ECA/CCA PSV ratio of > 1.89 provided sensitivity 71.9%, specificity 72.7%, and overall accuracy 72.5%. Conclusion ECA PSV an ECA/CCA PSV ratios appear useful metrics for the prediction of unilateral high-grade ECA stenosis.