title: Closed-cell stents present with higher velocities on duplex ultrasound compared with open-cell stents after carotid intervention: short- and mid-term results.
abstract: 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.
authors.affiliation: Division of Vascular Surgery, New York Presbyterian, New York, NY, USA.
authors.forename: Hafiz G
authors.initials: HG
authors.lastname: Hussain
authors.forename: Ritu
authors.initials: R
authors.lastname: Aparajita
authors.forename: Sikandar Z
authors.initials: SZ
authors.lastname: Khan
authors.forename: Combiz
authors.initials: C
authors.lastname: Rezayat
authors.forename: James F
authors.initials: JF
authors.lastname: McKinsey
authors.forename: Rajeev
authors.initials: R
authors.lastname: Dayal
mesh_terms: 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