title: Open-cell versus closed-cell stent design differences in blood flow velocities after carotid stenting.
abstract: OBJECTIVE
  The differential effect of open-cell vs closed-cell stent design configuration on carotid velocities detected by duplex ultrasound (DUS) imaging has not been established. To identify possible stent design differences in carotid velocities, we analyzed DUS studies obtained before and immediately after carotid artery stenting (CAS).
  
  
  METHODS
  In a series of 141 CAS procedures performed during a 3-year period, data from the first postinterventional DUS images and carotid angiograms were evaluated for each patient. Peak systolic velocities (PSV), end-diastolic velocities (EDV), and internal carotid artery/common carotid artery (ICA/CCA) PSV ratios were compared according to stent design. Differences in carotid velocities were analyzed using nonparametric statistical tests.
  
  
  RESULTS
  Completion angiograms revealed successful revascularization and <30% residual stenosis in each case. The 30-day stroke-death rate in this series was 1.6% and was unrelated to stent type. Postintervention DUS images were obtained a median of 5 days (interquartile range [IQR], 1-25 days) after CAS. Closed-cell stents were used in 41 procedures (29%) and open-cell stents in 100 (71%). The median PSV was 95.9 cm/s (IQR, 77-123 cm/s) for open-cell stents and 122 cm/s (IQR, 89-143 cm/s) for closed-cell stents, which was significantly higher (P = .007). Closed-cell stents also had significantly higher median EDVs (36 vs 29 cm/s; P =.006) and ICA/CCA PSV ratios (1.6 vs 1.1; P =.017). By DUS criteria, the carotid velocities in 45% of closed-cell stents exceeded the threshold of 50% stenosis for a nonstented artery compared with 26% of open-cell stents (P =.04). Closed-cell stents had a 2.2-fold increased risk of yielding abnormally elevated carotid velocities after CAS compared with open-cell stents (odds ratio, 2.2; 95% confidence interval, 1.02-4.9).
  
  
  CONCLUSIONS
  Carotid velocities are disproportionately elevated after CAS with closed-cell stents compared with open-cell stents. This suggests that the velocity criteria for quantifying stenosis may require modification according to stent design. The importance of these differences in carotid velocities related to stent design and the potential relationship with recurrent stenosis remains to be established.
authors.affiliation: Division of Vascular and Endovascular Surgery, Department of Surgery, Veterans Affairs North Texas Health Care System and the University of Texas Southwestern Medical Center, Dallas, TX 75390-9157, USA.
authors.forename: Damon S
authors.initials: DS
authors.lastname: Pierce
authors.forename: Eric B
authors.initials: EB
authors.lastname: Rosero
authors.forename: J Gregory
authors.initials: JG
authors.lastname: Modrall
authors.forename: Beverley
authors.initials: B
authors.lastname: Adams-Huet
authors.forename: R James
authors.initials: RJ
authors.lastname: Valentine
authors.forename: G Patrick
authors.initials: GP
authors.lastname: Clagett
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Timaran
mesh_terms: D000792:Angiography; D017130:Angioplasty / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D001783:Blood Flow Velocity; D017536:Carotid Artery, Common / Q000503:physiopathology / Q000601:surgery*; D002343:Carotid Artery, Internal / Q000503:physiopathology / Q000601:surgery*; D016893:Carotid Stenosis / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D011474:Prosthesis Design; D012039:Regional Blood Flow; D015607:Stents; D020521:Stroke / Q000209:etiology / Q000401:mortality; D013997:Time Factors; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex