Accuracy of carotid duplex is laboratory specific and must be determined by internal audit.
OBJECTIVE
To assess the accuracy of carotid duplex in a single vascular laboratory at the prediction of an angiographic 70% internal carotid artery stenosis.


METHODS
A retrospective review of all patients who underwent both carotid duplex and angiography in a 1-year period at a vascular unit which participates in the ACST trial.


METHODS
Peak systolic velocity was used as a primary end-point in carotid duplex examinations with a PSV > 130 cm/s used as an indication for angiographic assessment. Biplanar arch aortography and selective carotid catheterisation were performed as indicated and diameter reduction calculated by the ECST method.


RESULTS
The sensitivity of 130 cm/s for the detection of a 70% stenosis was 96% and the specificity 67%. If a PSV of 250 cm/s were used the sensitivity would be only 37% and specificity 96%.


CONCLUSIONS
Applying duplex criteria from one centre to another is inappropriate. Laboratory specific audit of duplex and angiography is essential before deciding to abandon preoperative angiography for carotid disease.
Curley
P J
PJ
Department of Vascular Surgery, Hull Royal Infirmary, U.K.
Norrie
L
L
Nicholson
A
A
Galloway
J M
JM
Wilkinson
A R
AR
D001027:Aortography; D001783:Blood Flow Velocity; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000000981:diagnostic imaging; D002404:Catheterization; D003287:Contrast Media; D005544:Forecasting; D006801:Humans; D007472:Iohexol; D007753:Laboratories / Q000592:standards; D008485:Medical Audit; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013599:Systole; D018616:Ultrasonography, Doppler, Duplex / Q000592:standards*
D003287:Contrast Media; D007472:Iohexol