title: Thin-cap fibroatheroma and large calcification at the proximal stent edge correlate with a high proportion of uncovered stent struts in the chronic phase.
abstract: OBJECTIVE
  A high proportion of uncovered stent struts is associated with late stent thrombosis after drug-eluting stent (DES) implantation, which frequently results in myocardial infarction or death. However, the predictors of uncovered stent struts remain unknown. Here, using optical coherence tomography (OCT), we studied the baseline tissue characteristics of the target coronary segment and evaluated their influence on the neointimal coverage of the strut in the chronic phase.
  
  
  METHODS
  We analyzed 118 coronary lesions treated with OCT-guided DES implantation. OCT examinations of target lesions were performed before and after DES implantation, and tissue characteristics were evaluated within 5 mm outer segment of both stent edges. At follow-up, stent strut coverage was assessed within 5 mm inner segment from each stent edge. On the basis of the proportion of uncovered stent struts in the chronic phase, target segments were divided into poorly covered (the highest quartile with % uncovered struts, n=29) and well-covered (the remaining lower quartiles with % uncovered struts, n=89) groups.
  
  
  RESULTS
  Clinical parameters were similar between the two groups. On baseline OCT images, thin-cap fibroatheroma (TCFA) and large calcification were more frequently observed in the poorly covered group than the well-covered group (10.3 vs. 0.0%, P=0.0032, and 27.6 vs. 9.0%, P=0.017, respectively). Furthermore, multivariable analysis showed TCFA and large calcification at the proximal edge, but not at the distal edge, were predictors of uncover stent struts.
  
  
  CONCLUSIONS
  TCFA and large calcification at the proximal stent edge are strong predictors of uncovered stent struts. OCT is useful for selecting stent landing sites in terms of future occurrence of uncovered stent struts.
authors.affiliation: aFirst Department of Internal Medicine, Nara Medical University, Nara bDepartment of Cardiology, Kawasaki Medical School, Okayama, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Ueda
authors.forename: Shiro
authors.initials: S
authors.lastname: Uemura
authors.forename: Makoto
authors.initials: M
authors.lastname: Watanabe
authors.forename: Yoko
authors.initials: Y
authors.lastname: Dote
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Goryo
authors.forename: Yu
authors.initials: Y
authors.lastname: Sugawara
authors.forename: Tsunenari
authors.initials: T
authors.lastname: Soeda
authors.forename: Satoshi
authors.initials: S
authors.lastname: Okayama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kawata
authors.forename: Rika
authors.initials: R
authors.lastname: Kawakami
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okura
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Saito
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology*; D054855:Drug-Eluting Stents; D005260:Female; D005355:Fibrosis; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D058426:Neointima; D016017:Odds Ratio; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000295:instrumentation*; D058226:Plaque, Atherosclerotic; D012042:Registries; D012307:Risk Factors; D013997:Time Factors; D041623:Tomography, Optical Coherence; D016896:Treatment Outcome; D061205:Vascular Calcification / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*