title: Impact of preinterventional plaque composition and eccentricity on late-acquired incomplete stent apposition after sirolimus-eluting stent implantation:  an intravascular ultrasound radiofrequency analysis.
abstract: OBJECTIVE
  The present study aimed to investigate differences in plaque morphology and components in between the target coronary artery lesion with and without late-acquired incomplete stent apposition (LISA) using radiofrequency analysis (virtual histology) of intravascular ultrasound data.
  
  
  BACKGROUND
  Incomplete stent apposition is frequently observed in patients with very late stent thrombosis after sirolimus-eluting stent implantation.
  
  
  METHODS
  The study group consisted of 70 coronary artery lesions in 43 patients who underwent elective coronary stenting for stable angina pectoris. Virtual histology intravascular ultrasound was performed at the implantation of stent and 12-month follow-up. LISA was defined as a separation of stent struts from the intimal surface of the arterial wall that had not been present at the time of stent implantation. The plaque eccentricity index (EI) was calculated as (lumen radius+maximal plaque thickness)/(lumen radius+minimal plaque thickness).
  
  
  RESULTS
  At 12-month follow-up, LISA occurred in 15 plaques (LISA group). Compared with the non-LISA group, the LISA group had significantly longer stents, a higher EI, smaller amount of fibro-fatty component (7.7±4.2 vs. 12.5±7.0%, P=0.01) and larger amount of necrotic core component (16.6±9.8 vs. 11.1±6.4%, P=0.06). Multivariate logistic regression analysis revealed that amount of necrotic core and plaque EI were independent positive predictors for LISA (odds ratio=1.4, 95% confidence interval=1.1-1.6, P=0.04 and 11.2, 1.9-64.9, P<0.01, respectively).
  
  
  CONCLUSIONS
  Plaques with increased amounts of necrotic core and higher eccentricity are associated with subsequent LISA after sirolimus-eluting stent implantation.
authors.affiliation: The Second Department of Internal Medicine, University of Toyama, Toyama, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Sato
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kameyama
authors.forename: Takahisa
authors.initials: T
authors.lastname: Noto
authors.forename: Takashi
authors.initials: T
authors.lastname: Nozawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inoue
mesh_terms: D000368:Aged; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D016009:Chi-Square Distribution; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D003328:Coronary Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000473:pathology; D054855:Drug-Eluting Stents; D005260:Female; D005355:Fibrosis; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009336:Necrosis; D016017:Odds Ratio; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000295:instrumentation*; D058226:Plaque, Atherosclerotic; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D018570:Risk Assessment; D012307:Risk Factors; D020123:Sirolimus / Q000008:administration & dosage*; D013997:Time Factors; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional
chemical_list: D002317:Cardiovascular Agents; D020123:Sirolimus