title: Angioscopic evaluation of neointima coverage: sirolimus drug-eluting stent versus bare metal stent.
abstract: BACKGROUND
  The process of neointima formation after bare metal stent (BMS) implantation has been previously elucidated by angioscopic observations; however, that after drug-eluting stent (DES) implantation has not been clarified. Therefore, we compared the angioscopic appearance of neointima over DESs with that over BMSs 6 months after implantation.
  
  
  RESULTS
  Patients who received an implantation of a BMS (n = 13) or a sirolimus DES (n = 24) were included in this study. Angiographic and angioscopic examinations were performed at 6 months. The color of the stented lesion (white or yellow), coverage of stent by neointima (not covered, covered by a thin layer, or buried under neointima), and thrombus at the stented lesion (presence or absence) were angioscopically evaluated. Of the 24 lesions in which a DES was implanted, 11 (46%) had a part where the stent strut had no coverage, 21 (88%) had a part where it was covered by a thin layer, and 11 (46%) had a part where it was buried under neointima. Of the 13 lesions in which a BMS was implanted, 1 (8%) lesion had a part where the stent strut had no coverage, 4 (31%) lesions had a part where it was covered by a thin layer, and 13 (100%) lesions had a part where it was buried under neointima. The prevalence of a stent buried under neointima (46% vs 100%, P = .001) was lower and that of thrombus (42% vs 8%, P = .03) was higher in DES-implanted lesions as compared with BMS-implanted lesions. The prevalence of thrombus (64% vs 17%, P = .005) was higher in the yellow area than in the white area when a DES was implanted.
  
  
  CONCLUSIONS
  Sirolimus DESs, as compared with BMSs, were poorly covered by neointima and were accompanied by thrombus especially when there was a yellow plaque under the stents. Thus, the thrombogenic potential in DES-implanted lesions may be sustained by the inhibition of neointima formation over thrombogenic plaques.
authors.affiliation: Cardiovascular Division, Osaka Police Hospital, Osaka 543-0035, Japan.
authors.forename: Jota
authors.initials: J
authors.lastname: Oyabu
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Ueda
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Ogasawara
authors.forename: Katsuki
authors.initials: K
authors.lastname: Okada
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hirayama
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Kodama
mesh_terms: D000368:Aged; D017546:Angioscopy; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D016503:Drug Delivery Systems; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D020123:Sirolimus / Q000008:administration & dosage* / Q000627:therapeutic use; D015607:Stents / Q000009:adverse effects; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D013997:Time Factors; D017539:Tunica Intima / Q000473:pathology*
chemical_list: D008670:Metals; D020123:Sirolimus