Background and purpose: While internal carotid peak systolic velocity (IPSV) is reportedly the best Doppler parameter for predicting lower grades of carotid artery stenosis, the internal carotid end-diastolic velocity (IEDV) or the ratio of IPSV to common carotid end-diastolic velocity (CEDV) is helpful in increasing prediction of higher grade stenoses. It is important to examine the consistency of these findings across machine and technician.
Methods: Using data from 10 devices from the Asymptomatic Carotid Atherosclerosis Study, we examined the predictive ability of seven Doppler parameters: IPSV, IEDV, CEDV, common carotid peak systolic velocity (CPSV), and the ratios of IPSV/ CEDV, IEDV/CEDV, and IEDV/CEDV. To assess the agreement between Doppler and arteriography in classifying percent stenosis above or below a given criterion, sensitivity, specificity, area under the receiver operating curve, and kappa statistics were obtained from logistic models. The single best Doppler parameter for each of two grades of stenosis (60% and 80%) was determined, and its predictive ability was compared with that of IPSV. The usefulness of IEDV or IPSV/CEDV in addition to IPSV to determine higher grade stenosis was examined.
Results: IPSV was the best predictor in 9 of 10 devices at 60% and in 4 devices at 80% stenosis. When another parameter was better than IPSV, the improvement was minimal. Including IEDV or IPSV/CEDV in addition to IPSV did not notably improve predictive ability.
Conclusions: IPSV is the single best Doppler parameter for distinguishing severe (> 80%) from less severe carotid stenosis. Information from other Doppler parameters in addition to IPSV is unlikely to be helpful.