title: Vascular responses to a biodegradable polymer (polylactic acid) based biolimus A9-eluting stent in porcine models.
abstract: OBJECTIVE
  The time-dependent changes in endothelial and healing properties of coronary arteries implanted with a biodegradable polymer-based biolimus A9-eluting stent (BioPol-BES) have not been investigated. We evaluated the short-term and the long-term in vivo response of BioPol-BES, as compared to a permanent polymer-based sirolimus-eluting stent (PermPol-SES), and a bare metal stent (BMS).
  
  
  RESULTS
  Overlapping stents were placed in 33 swine (n=11 for BES, SES, and BMS, respectively) for two and four weeks and single stents in 30 miniature pigs (n=18 for BES, n=9 for SES, n=3 for BMS) for three, nine and 15-month evaluations. The vessel patency, arterial healing and endothelialisation were assessed by angiography, histopathology and scanning electron microscopy. At four weeks, the endothelialisation at overlapping stent regions was greater with BioPol-BES (87.8±3.7%) and BMSs (98.0±0.4%) than with PermPol-SES (66.4±3.2%). The inflammation score in vessels implanted with single BioPol-BES increased slightly from three to 15 months (0.00±0.00 to 0.28±0.14), while this increase was more pronounced with PermPol-SES (0.11±0.07 to 1.56±0.68). Compared to BMS moderate lymphocyte infiltration was seen with BioPol-BES, and marked granulomatous formation with PermPol-SES.
  
  
  CONCLUSIONS
  The level of endothelial coverage in BioPol-BES was comparable to BMS at four weeks, with no significant increase of inflammatory reaction up to 15 months.
authors.affiliation: Research & Development Centre, Terumo Corporation, Kanagawa, Japan. Hitomi_Hagiwara@terumo.co.jp
authors.forename: Hitomi
authors.initials: H
authors.lastname: Hagiwara
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Hiraishi
authors.forename: Hisako
authors.initials: H
authors.lastname: Terao
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Hirai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sakaoka
authors.forename: Masashige
authors.initials: M
authors.lastname: Sasaki
authors.forename: Satomi
authors.initials: S
authors.lastname: Murota
authors.forename: Katsumi
authors.initials: K
authors.lastname: Inoue
authors.forename: Junji
authors.initials: J
authors.lastname: Kimura
mesh_terms: D000800:Angioplasty, Balloon / Q000009:adverse effects / Q000295:instrumentation*; D000818:Animals; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D054855:Drug-Eluting Stents; D042783:Endothelial Cells / Q000473:pathology; D006099:Granuloma / Q000473:pathology; D007249:Inflammation / Q000473:pathology; D019344:Lactic Acid; D008214:Lymphocytes / Q000473:pathology; D008670:Metals; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D011091:Polyesters; D011108:Polymers; D011474:Prosthesis Design; D020123:Sirolimus / Q000008:administration & dosage / Q000031:analogs & derivatives*; D013552:Swine; D013556:Swine, Miniature; D013997:Time Factors; D014463:Ultrasonography; D014654:Vascular Patency; D014945:Wound Healing
chemical_list: D002317:Cardiovascular Agents; D008670:Metals; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); C518022:umirolimus; D020123:Sirolimus