title: Serial Evaluation of Vascular Response After Implantation of a New Sirolimus-Eluting Stent With Bioabsorbable Polymer (MISTENT): an optical coherence tomography and histopathological study.
abstract: BACKGROUND
  Novel vascular scaffolds aim at equipoise between safety and efficacy. Intravascular optical coherence tomography (OCT) allows in-vivo serial assessment of stent-vessel interactions with high resolution and frequent sampling and may complement histology assessment. We investigated the vascular response to a novel absorbable coating sirolimus-eluting stent (AC-SES) by means of serial OCT and histology evaluation in a porcine model.
  
  
  METHODS
  One AC-SES and one bare-metal stent (BMS) were implanted in separate coronary arteries of three Yucatan mini-swine. Serial OCT was performed post procedure and at 3-, 28-, 90-, and 180-day follow-up. Normalized optical density (NOD) was used for the assessment of tissue response over time. Histological evaluation was performed at day 180.
  
  
  RESULTS
  A total of 6408 stent struts were analyzed. OCT revealed 100% of struts covered at 28 days, and a significant difference in NOD from 3 to 28 days (0.64 ± 0.07 vs 0.71 ± 0.05, respectively; P<.001) in the AC-SES group. Neointimal thickness was 0.14 ± 0.08 mm, 0.17 ± 0.11 mm, and 0.16 ± 0.09 mm in the AC-SES group and 0.18 ± 0.10 mm, 0.14 ± 0.09 mm, and 0.10 ± 0.08 mm in the BMS group, while rates of uncovered struts were 0%, 0%, and 3.1% and 1.4%, 7.8%, and 21.5%, respectively, at 28, 90, and 180 days. Minimal inflammation and a mature endothelialization were demonstrated in both groups by histology.
  
  
  CONCLUSIONS
  OCT serial assessment of vascular response suggested NIH maturation 28 days following AC-SES implantation in pigs. These findings, coupled with histological demonstration of low inflammation scores and complete endothelial coverage as measured at 180 days, suggest a satisfactory healing response to AC-SES.
authors.affiliation: Harrington Heart and Vascular Institute, University Hospitals Case Medical Center, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106 USA.
authors.forename: Guilherme F
authors.initials: GF
authors.lastname: Attizzani
authors.forename: Hiram G
authors.initials: HG
authors.lastname: Bezerra
authors.forename: Daniel
authors.initials: D
authors.lastname: Chamié
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Fujino
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Spognardi
authors.forename: James R L
authors.initials: JR
authors.lastname: Stanley
authors.forename: Hirosada
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Emile
authors.initials: E
authors.lastname: Mehanna
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Wenda C
authors.initials: WC
authors.lastname: Carlyle
authors.forename: James B
authors.initials: JB
authors.lastname: McClain
authors.forename: Marco A
authors.initials: MA
authors.lastname: Costa
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000473:pathology / Q000517:prevention & control; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology*; D004195:Disease Models, Animal; D054855:Drug-Eluting Stents; D004730:Endothelium, Vascular / Q000473:pathology; D005500:Follow-Up Studies; D058426:Neointima / Q000473:pathology; D062645:Percutaneous Coronary Intervention / Q000295:instrumentation* / Q000379:methods; D020123:Sirolimus; D013552:Swine; D013556:Swine, Miniature; D013997:Time Factors; D041623:Tomography, Optical Coherence
chemical_list: D020123:Sirolimus