title: Comparison of two different sampling intervals for optical coherence tomography evaluation of neointimal healing response after coronary stent implantation.
abstract: OBJECTIVE
  Optical coherence tomography (OCT) is widely used for evaluation of healing response to stent implantation. We sought to test the agreement between the 1-mm and 0.6-mm sampling intervals for assessment of the percentage of uncovered and malapposed struts by OCT.
  
  
  METHODS
  Thirty-eight patients presenting with acute coronary syndrome were randomized to receive either a titanium-nitride-oxide-coated stent (n=19) or an everolimus-eluting stent (n=19). Neointimal strut coverage and strut apposition were evaluated by OCT at 2-month follow-up. Two independent investigators performed offline OCT image analysis at 1-mm intervals. One investigator repeated the measurements at 0.6-mm intervals and measurements were compared between the two sampling intervals.
  
  
  RESULTS
  At a median follow-up of 60 [8] days, 694 cross-sections (7603 struts) and 1138 cross-sections (12,331 struts) were analysed at 1-mm and at 0.6-mm intervals, respectively. The median [IQR] percentage of uncovered struts was 3.27% [11.1] versus 3.38% [9.76] (p=0.001), and the mean (±SD) percentage was 7.69±9.99% versus 6.27±8.14% (p=0.004), for the 1-mm sampling interval versus the 0.6-mm sampling interval analysis, respectively; the median percentage of malapposed struts was 0.42% [2.04] versus 0.12% [1.63], respectively, (p=0.003). The intraclass correlation coefficient between the two observers for the percentage of uncovered struts was 0.95.
  
  
  CONCLUSIONS
  The OCT-evaluated strut-level measurements of neointimal healing after stent implantation differ significantly between the 1-mm and the 0.6-mm sampling intervals.
authors.affiliation: Heart Center, Turku University Hospital, University of Turku, Turku, Finland. Electronic address: viveva@utu.fi.
authors.forename: Ville
authors.initials: V
authors.lastname: Varho
authors.affiliation: Heart Centre, Satakunta Central Hospital, Pori, Finland.
authors.forename: Wail
authors.initials: W
authors.lastname: Nammas
authors.affiliation: Heart Center, Turku University Hospital, University of Turku, Turku, Finland; Heart Centre, Satakunta Central Hospital, Pori, Finland.
authors.forename: Tuomas O
authors.initials: TO
authors.lastname: Kiviniemi
authors.affiliation: Department of Cardiology, Central Ostrobothnia Central Hospital, Kokkola, Finland.
authors.forename: Jussi
authors.initials: J
authors.lastname: Sia
authors.affiliation: Cardiology Unit, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Hannu
authors.initials: H
authors.lastname: Romppanen
authors.affiliation: Heart Center, Turku University Hospital, University of Turku, Turku, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Pietilä
authors.affiliation: Heart Center, Turku University Hospital, University of Turku, Turku, Finland.
authors.forename: Juhani K
authors.initials: JK
authors.lastname: Airaksinen
authors.affiliation: Heart Centre, Satakunta Central Hospital, Pori, Finland.
authors.forename: Pasi P
authors.initials: PP
authors.lastname: Karjalainen
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging / Q000628:therapy*; D000368:Aged; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000628:therapy; D054855:Drug-Eluting Stents; D000068338:Everolimus / Q000494:pharmacology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D058426:Neointima / Q000473:pathology; D015588:Observer Variation; D062645:Percutaneous Coronary Intervention / Q000295:instrumentation* / Q000379:methods; D011446:Prospective Studies; D016037:Single-Blind Method; D018709:Statistics, Nonparametric; D013997:Time Factors; D014025:Titanium / Q000494:pharmacology*; D041623:Tomography, Optical Coherence / Q000379:methods*; D014945:Wound Healing / Q000502:physiology
chemical_list: C434243:titanium-nitride-oxide; D000068338:Everolimus; D014025:Titanium
keywords: Malapposed struts; Neointimal healing; OCT; Sampling interval; Uncovered struts