Grading carotid intrastent restenosis: a 6-year follow-up study.
OBJECTIVE
The accuracy of carotid ultrasound has not been well established in predicting intrastent restenosis (ISR) after carotid artery stenting (CAS). The aim of this study is to determine different degrees of ISR using ultrasound velocity criteria compared to percentage of stenosis at angiography.


METHODS
This is a 6-year prospective study. After CAS procedure, each patient underwent angiography for measuring ISR (NASCET method) which was compared to peak systolic velocity (PSV), end diastolic velocity (EDV), and the ratio between PSV of internal carotid artery and common carotid artery (ICA/CCA). This was done within 48 hours, thus creating a baseline value. Ultrasound (US) examination was performed at day 30, at 3, 6, 9, and 12 months, and then yearly. Patients with an increase in PSV greater than 3 times the baseline value or in presence of PSV >or=200 cm/s underwent angiography.


RESULTS
814 CAS procedures, 6427 US examinations, and 1123 angiographies were performed. ISR >or=70% and ISR >or=50% was detected, respectively, in 22 patients and in 73 patients. We defined velocity criteria for grading carotid ISR: PSV <or=104 cm/s, if <30% stenosis; PSV:105 to 174 cm/s if 30% to 50% stenosis; PSV:175 to 299 cm/s if a 50% to 70% stenosis; PSV >or=300 cm/s, EDV >or=140 cm/s, and ICA/CCA >or=3.8 if a >or=70% stenosis. Receiver operator characteristic (ROC) curves for ISR >or=70% were, respectively, for PSV, EDV, and ICA/CCA: 0.99, 0.98, and 0.99.


CONCLUSIONS
US grading of carotid ISR can guarantee a correct follow-up after CAS if new customized velocity criteria are validated by skilled operators using a specific protocol of follow-up in a certified laboratory.
Setacci
Carlo
C
Department of Surgery, Vascular and Endovascular Surgery Unit, University of Siena, Italy.
Chisci
Emiliano
E
Setacci
Francesco
F
Iacoponi
Francesca
F
de Donato
Gianmarco
G
D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery; D002533:Cerebral Angiography; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015607:Stents; D018616:Ultrasonography, Doppler, Duplex