title: Early coverage of drug-eluting stents analysed by optical coherence tomography: evidence of the impact of stent apposition and strut characteristics on the neointimal healing process.
abstract: OBJECTIVE
  Previous studies have associated issues such as incomplete stent apposition with delayed healing and adverse events (stent thrombosis). The aim of this study was to evaluate the impact of strut apposition and stent type on the progression of stent strut coverage.
  
  
  RESULTS
  We evaluated in vivo in porcine models the follow-up response and coverage characteristics of well-apposed and malapposed segments of drug-eluting stents (DES) (CYPHER, PROMUS Element and Orsiro) and the Absorb bioresorbable vascular scaffold (BVS) by optical coherence tomography (OCT) sequentially, at baseline, and at one week and four weeks of follow-up. Supporting results were provided by histological analysis performed at four-week follow-up and computer simulation describing the shear characteristics around apposed and non-apposed struts. A total of 325 cross-sections containing 3,166 struts were analysed. The extent of malapposition decreased over time as a result of neointimal healing (from 7.1% at baseline to 0% at four weeks; p=0.03). At one week, 13.6% of struts in well-apposed segments were still uncovered versus 19.2% of struts in malapposed cross-sections and 77.8% of NASB struts (p<0.01). At four-week follow-up, 3.1% of struts were uncovered in well-apposed cross-sections vs. 1.6% in malapposed cross-sections and 35.7% of NASB struts (p<0.01). A comparison of the apposed segments revealed that the thin-strut Orsiro had only 1.3% of uncovered struts at one week while PROMUS Element, CYPHER and BVS had 6.6%, 48.4% and 16.2% of struts still uncovered, respectively.
  
  
  CONCLUSIONS
  This study shows that early coverage is influenced by stent apposition as well as platform strut characteristics (stent type). At four weeks, NASB struts remained a focus of delayed endothelialisation.
authors: National Heart Centre Singapore, Singapore.
authors: Renick
authors: R
authors: Lee
authors: Nicolas
authors: N
authors: Foin
authors: Jaryl
authors: J
authors: Ng
authors: John
authors: J
authors: Allen
authors: Nicole
authors: N
authors: Soh
authors: Ivy
authors: I
authors: Ang
authors: Winston
authors: W
authors: Shim
authors: Ryo
authors: R
authors: Torii
authors: Philip
authors: P
authors: Wong
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000379:methods; D000818:Animals; D003198:Computer Simulation; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000473:pathology; D003331:Coronary Vessels / Q000473:pathology / Q000601:surgery*; D054855:Drug-Eluting Stents; D006801:Humans; D023421:Models, Animal; D058426:Neointima / Q000473:pathology; D011474:Prosthesis Design; D020123:Sirolimus / Q000008:administration & dosage / Q000627:therapeutic use*; D013552:Swine; D041623:Tomography, Optical Coherence / Q000379:methods; D016896:Treatment Outcome; D014945:Wound Healing
chemical_list: D020123:Sirolimus