Healing of carotid stents: a prospective duplex ultrasound study.
OBJECTIVE
To study the dynamics of carotid stent healing over a 2-year period using duplex ultrasound imaging.


METHODS
One hundred twelve patients with 121 successfully stented carotid arteries were examined with color-coded duplex ultrasound the day after the stent procedure and at 1, 3, 6, 12, and 24 months in follow-up. The maximal thickness and echogenicity of the layer between the stent and the perfused lumen (SPL) were evaluated. Echogenicity was classified as echogenic if the SPL layer was clearly detected in B mode and echolucent if the SPL layer was barely visible in B mode, its border defined by assistance of color-coded flow.


RESULTS
At day 1, an echolucent SPL layer with a median thickness of 0.7 mm was interpreted as a thrombotic layer, which decreased at 1 month to practically zero (i.e., not detectable). In follow-up, increases in thickness (mainly up to 6 months) and echogenicity (up to 12 months) of the SPL layer were interpreted as neointimal ingrowth. At 3, 6, and 12 months, the median maximal thickness of the SPL layer was 0.5 mm, 0.9 mm, and 1.0 mm, respectively, whereas the percentage of patients with an echogenic SPL layer was 27% (32/119), 56% (66/117), and 95% (105/110), respectively, at the same time intervals. No further change was observed at the 24-month examination.


CONCLUSIONS
Three phases of carotid stent incorporation are defined: (1) an early unstable period soon after stent placement with an echolucent (thrombotic) SPL layer, (2) a moderately unstable phase with ingrowing neointima (1-12 months), and (3) a stable phase from the second year on. These data may indicate the need for different intensities of therapy and surveillance intervals.
Willfort-Ehringer
Andrea
A
Departments of Medical Angiology, University of Vienna, Medical School, Vienna, Austria. andrea.willfort@akhwien.ac.at
Ahmadi
Ramazanali
R
Gschwandtner
Michael E
ME
Haumer
Angelika
A
Heinz
Gottfried
G
Lang
Wilfried
W
Ehringer
Herbert
H
D000368:Aged; D017536:Carotid Artery, Common; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D015607:Stents; D018616:Ultrasonography, Doppler, Duplex; D014945:Wound Healing