Changes Over Time in Optimal Duplex Threshold for the Identification of Patients Eligible for Carotid Endarterectomy

Abstract

Background and Purpose-Two surgical trials established that carotid endarterectomy is beneficial to symptomatic patients who have a severe internal carotid artery (ICA) stenosis on angiograms. Duplex ultrasonography-derived hemodynamic parameters show a good correlation with angiography and are often used for detecting severe ICA stenoses. However, duplex performance is ultrasound machine and operator dependent. Over time both may change, possibly affecting duplex performance. We compared duplex performance of 2 time periods in 1 specific vascular laboratory using angiography as the gold standard. Methods-Consecutive patients who underwent both angiography and duplex examinations of the ICA were evaluated (first period, 60 patients; second period, 61 patients). Peak systolic velocity and several other hemodynamic parameters and ratios were analyzed by receiver operating characteristic curves in their ability to detect severe ICA stenoses. The optimal parameter and threshold were determined for each period. Subsequently, duplex test characteristics were compared after the optimal thresholds of both the first and the second periods were applied in the second period. Results-In both periods peak systolic velocity of the ICA was the best test parameter; areas under the receiver operating characteristic curve were similar (0.957 and 0.954, respectively). However, the optimal threshold was different. The optimal threshold in the second period was 270 cm/s. When the optimal threshold of 210 cm/s of the first period was applied in the second period, test characteristics changed significantly. Sensitivity increased from 98% to 100%, and specificity decreased from 85% to 71% (Pϭ0.004). Conclusions-The optimal threshold for detecting severe ICA stenoses with duplex ultrasonography in our laboratory changed over time. Individual laboratories should assess duplex accuracy regularly and adjust adopted criteria if necessary to keep diagnostic performance optimal.

Asymptomatic Carotid Artery Stenosis and the Risk of New Vascular Events in Patients With Manifest Arterial Disease

“…The severity of CAS was evaluated on basis of the blood flow velocity patterns. 15 The greatest stenosis observed on the right or the left side of the common or internal carotid artery was taken to determine the severity of carotid artery disease. Accordingly, all patients were classified into one of the following categories: absence of stenosis; mild stenosis (Ͻ50% diameter stenosis, peak systolic velocity [PSV] Ͼ100 to Յ150 cm/s); moderate stenosis (Ն50% to 69% diameter stenosis, PSV Ͼ150 to Յ210 cm/s); severe stenosis (Ն70% to 99% diameter stenosis, PSV Ͼ210 cm/s or preocclusion PSV Ͼ210 cm/s and distal PSV Ͻ40 cm/s or subtotal PSV Ͻ50 cm/s and severe plaque); and occlusion (100% diameter stenosis, no flow).…”

Arterial stiffness and progression of structural brain changes

“…Carotid artery stenosis $70% was defined as peak systolic velocity .210 cm/s, since this was found before to be the best parameter. 32 Total parenchymal cerebral blood flow (pCBF) was calculated by summing the flow through the left and right ICAs and BA (mL/min) per 100 mL brain parenchymal volume. 29 Data analyses.…”

Doppler-Ultrasound and computed tomography correlation for quantification of carotid stenosis

“…Moreover, it has been shown that peak systolic velocity (PSV) in the internal carotid artery is the best single velocity parameter for quantifying stenosis [9,10] . Alternatively, CTA may be used in the assessment of carotid artery stenosis [11,12] .…”