Wall mechanics of the stented extracranial carotid artery.
OBJECTIVE
Abrupt compliance changes and concomitant nonlaminar flow patterns may contribute to endothelial dysfunction and subsequent neointimal thickening. The aim of this study was to test the feasibility of wall mechanics measurement using B-mode ultrasound image analysis by dedicated software in the stented human carotid artery.


METHODS
Carotid Wallstents (Schneider) were placed in the extracranial carotid arteries of 15 patients. B-mode ultrasound examination was performed with a 7.5-MHz probe on the carotid artery upstream; at the proximal, mid, and distal stent levels; downstream from the stent; and on the contralateral internal and common carotid arteries. Carotid diameter (d) and systolic diameter changes (Deltad) were measured with a dedicated image processing system (IO version 3.1, IODP), while pulse blood pressure (DeltaP) was measured. Diameter compliance (Cd) and distensibility coefficient (DC) were calculated as Cd=2Deltad/DeltaP and DC=2Deltad/DeltaP/d and compared between measurement sites.


RESULTS
The evaluation could be completed in 8 of 15 patients. Compliance was significantly lower at the proximal, mid, and distal stent levels (27.77+/-1.11, 27.38+/-1.08, 27.38+/-1.09x10(-3) mm x kPa(-1)) than upstream (103.3+/-36.7x10(-3) mm x kPa(-1)), downstream (91.5+/-41.3x10(-3) mm x kPa(-1)), or on the contralateral internal (87.6+/-28x10(-3) mm x kPa(-1)) and common (149.3+/-47.6x10(-3) mm x kPa(-1)) carotid arteries.


CONCLUSIONS
Stenting of the extracranial carotid artery induces a compliance mismatch between the native and the stented artery.
Vernhet
Hélène
H
Laboratory of Cardiovascular Physiology, Montpellier I University, Faculty of Medicine, Avenue Kennedy, Nimes F 30907 France.
Jean
Beatrix
B
Lust
Stephan
S
Laroche
Jean Pierre
JP
Bonafé
Alain
A
Sénac
Jean Paul
JP
Quéré
I
I
Dauzat
Michel
M
D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D019917:Blood Vessel Prosthesis Implantation; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D002340:Carotid Artery Diseases / Q000601:surgery; D003187:Compliance; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015607:Stents; D013314:Stress, Mechanical; D014463:Ultrasonography; D014654:Vascular Patency / Q000502:physiology