title: The effect of shear stress on neointimal response following sirolimus- and paclitaxel-eluting stent implantation compared with bare-metal stents in humans.
abstract: OBJECTIVE
  We aimed to explore the relationship of neointimal thickness (NT) to shear stress (SS) after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) compared with bare-metal stents (BMS). We then tested the hypothesis that drug elution attenuates the SS effect.
  
  
  BACKGROUND
  Neointimal thickness after BMS implantation has been associated with SS; pertinent data for drug-eluting stents (DES) are limited.
  
  
  METHODS
  Three-dimensional coronary artery and stent reconstruction was performed in 30 patients at 6-month follow-up after SES (n = 10), PES (n = 10), or BMS (n = 10) implantation. Baseline SS at the stent surface was calculated using computational fluid dynamics and NT at follow-up was computed in 3-dimensional space.
  
  
  RESULTS
  Neointimal thickness was lower in DES versus BMS (0.03 ± 0.07 mm vs. 0.16 ± 0.08 mm, p < 0.001) and maximum NT was reduced in SES versus PES (0.33 ± 0.13 mm vs. 0.46 ± 0.13 mm, p = 0.025). In the total population, both SS (slope: -0.05 mm/Pa, p < 0.001) and DES (coefficient for DES vs. BMS: -0.17 mm, p = 0.003) were independent predictors of NT. Subgroup analysis demonstrated a significant negative relationship of NT to SS in PES (slope: -0.05 mm/Pa, p = 0.016) and BMS (slope: -0.05 mm/Pa, p = 0.001). Sirolimus elution significantly attenuated the effect of SS on NT (interaction coefficient for SES vs. BMS: 0.04 mm/Pa, p = 0.023), whereas the SS effect remained unchanged in PES (interaction coefficient for PES vs. BMS: 0.01 mm/Pa, p = 0.71).
  
  
  CONCLUSIONS
  Neointimal thickness is significantly correlated (inversely) to SS in PES as in BMS. Sirolimus elution abrogates the SS effect on the neointimal response following stent implantation, whereas the SS effect is unchanged in PES.
authors.affiliation: Michailideion Cardiac Center, University of Ioannina, Ioannina, Greece.
authors.forename: Michail I
authors.initials: MI
authors.lastname: Papafaklis
authors.forename: Christos V
authors.initials: CV
authors.lastname: Bourantas
authors.forename: Panagiotis E
authors.initials: PE
authors.lastname: Theodorakis
authors.forename: Christos S
authors.initials: CS
authors.lastname: Katsouras
authors.forename: Katerina K
authors.initials: KK
authors.lastname: Naka
authors.forename: Dimitrios I
authors.initials: DI
authors.lastname: Fotiadis
authors.forename: Lampros K
authors.initials: LK
authors.lastname: Michalis
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects / Q000295:instrumentation*; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D049109:Cell Proliferation / Q000187:drug effects; D016009:Chi-Square Distribution; D003198:Computer Simulation; D017023:Coronary Angiography; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology; D054855:Drug-Eluting Stents; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D016014:Linear Models; D008297:Male; D008670:Metals; D008875:Middle Aged; D008955:Models, Cardiovascular; D017239:Paclitaxel / Q000008:administration & dosage*; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D020123:Sirolimus / Q000008:administration & dosage*; D015607:Stents; D013314:Stress, Mechanical; D013997:Time Factors; D016896:Treatment Outcome; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology*; D018084:Ultrasonography, Interventional
chemical_list: D002317:Cardiovascular Agents; D008670:Metals; D017239:Paclitaxel; D020123:Sirolimus