Closed-cell stents present with higher velocities on duplex ultrasound compared with open-cell stents after carotid intervention: short- and mid-term results.
BACKGROUND
The purpose of this study was to evaluate the effect of carotid cell design on duplex ultrasound velocity readings in the immediate postoperative period and over time.


METHODS
A prospective database encompassing all patients treated with carotid artery stents between 2003 and 2008 was established and analyzed for stent type (closed-cell vs. open-cell), indications, and comorbidities. Patients were followed up clinically and with duplex ultrasound immediately after surgery, and every 6 months thereafter. Peak systolic velocities (PSV), end diastolic velocities (EDV), and internal carotid artery (ICA) to common carotid artery (CCA) ratios of PSV were recorded.


RESULTS
A total of 214 interventions with 157 (73.3%) open-cell and 57 (26.7%) closed-cell types of carotid stents were performed in 205 patients. Two groups were similar regarding demographics, comorbidities, lesions characteristics, and stent length and diameter. The only difference was a significantly higher mean age (74.4 ± 10.1 vs. 70.9 ± 9.7 years; p = 0.027) and a history of myocardial infarction (34.5% vs. 15.6%; p = 0.004) in the closed-cell group versus open-cell group. Immediately after surgery PSV (115.9 ± 66.1 vs. 93.1 ± 38.7 cm/s; p = 0.003) and ICA/CCA ratio (2.08 ± 1.66 vs. 1.45 ± 0.52; p = 0.001) were significantly higher in closed-cell compared with open-cell group. This difference persisted during the follow-up period of 20.2 +/- 16.4 months; PSV (147.2 ± 108.8 vs. 110.0 ± 51.9; p = 0.003) and ICA/CCA ratio (2.61 ± 2.31 vs. 1.76 ± 0.81; p = 0.001). Patients with diabetes and calcified lesions had higher PSV and ICA/CCA ratio immediately after surgery (p > 0.05 and p < 0.05 for those with diabetes and calcified lesions, respectively) and over time. The number of readings showing significant restenosis (PSV >300 cm/s) over time were significantly higher in closed-cell 5 (8.7%) versus open-cell 1 (0.06%). EDV was not statistically different in the two groups (p > 0.05).


CONCLUSIONS
Our study suggests that duplex criteria to screen for poststent restenosis may require modification according to stent-type. However, long-term effect of stent design on restenosis is still to be established.
Hussain
Hafiz G
HG
Division of Vascular Surgery, New York Presbyterian, New York, NY, USA.
Aparajita
Ritu
R
Khan
Sikandar Z
SZ
Rezayat
Combiz
C
McKinsey
James F
JF
Dayal
Rajeev
R
D000368:Aged; D000369:Aged, 80 and over; D017130:Angioplasty / Q000009:adverse effects / Q000295:instrumentation*; D001783:Blood Flow Velocity; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D016009:Chi-Square Distribution; D006801:Humans; D008875:Middle Aged; D009519:New York City; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011474:Prosthesis Design; D012008:Recurrence; D012039:Regional Blood Flow; D012042:Registries; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex