Carotid artery stents: early and intermediate follow-up with Doppler US.
OBJECTIVE
To determine whether ultrasound (US) is a sensitive follow-up method after placement of a carotid artery stent for the detection of significant stenosis, occlusion, and other complications at early and intermediate follow-up.


METHODS
Doppler US examinations were performed after stent placement in 170 carotid arteries in 119 patients with angiographic correlation. Prospective diagnostic US criteria for stenosis were peak-systolic velocity greater than 1.25 m/sec, internal carotid artery (ICA) to common carotid artery (CCA) peak-systolic velocity ratio of greater than or equal to 3:1, and intrastent doubling of peak-systolic velocity. Retrospective criteria for stenosis were also applied: peak-systolic velocity greater than 1.7 m/sec, ICA end-diastolic velocity greater than 0.4 m/sec, ICA/CCA peak-systolic velocity ratio greater than 2.0, and ICA/CCA end-diastolic velocity ratio greater than 2.4.


RESULTS
Eighty-seven immediate and 83 intermediate (average, 7.3 months) follow-up US examinations were performed. Two stent occlusions were detected. One or more prospective US criteria were abnormal in 26 arteries with a stent. One or more retrospective criteria were positive in 47 arteries. Angiography showed corresponding findings, with only one significant stenosis (63%) in the ICA stents. Moderate collapse of a CCA stent was depicted at US.


CONCLUSIONS
Only one significant recurrent stenosis was detected, and no significant stenoses were missed at US. US successfully depicted carotid artery stent occlusion and a moderate stent collapse. Sensitivity in the detection of intrastent stenosis is promising. Further study to refine US criteria in a study with longer term follow-up is needed owing to the lack of significant recurrent stenosis in the intermediate follow-up group.
Robbin
M L
ML
Department of Radiology, University of Alabama at Birmingham, AL 35233-1924, USA.
Lockhart
M E
ME
Weber
T M
TM
Vitek
J J
JJ
Smith
J K
JK
Yadav
J
J
Mathur
A
A
Iyer
S S
SS
Roubin
G S
GS
D000368:Aged; D001783:Blood Flow Velocity; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011859:Radiography; D012008:Recurrence; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D015607:Stents; D013997:Time Factors; D018615:Ultrasonography, Doppler, Color