title: Optical coherence tomography patterns of stent restenosis.
abstract: BACKGROUND
  Stent restenosis is an infrequent but poorly understood clinical problem in the drug-eluting stent era. The aim of the study was to evaluate the morphologic characteristics of stent restenosis by optical coherence tomography (OCT).
  
  
  METHODS
  Patients (n = 24, 25 vessels) presenting with angiographically documented stent restenosis were included. Quantitative OCT analysis consisted of lumen and stent area measurement and calculation of restenotic tissue area and burden. Qualitative restenotic tissue analysis included assessment of tissue structure, backscattering and symmetry, visible microvessels, lumen shape, and presence of intraluminal material.
  
  
  RESULTS
  By angiography, restenosis was classified as diffuse, focal, and at the margins in 9, 11, and 5 vessels, respectively. By OCT, restenotic tissue structure was layered in 52%, homogeneous in 28%, and heterogeneous in 20%. The predominant backscatter was high in 72%. Microvessels were visible in 12%. Lumen shape was irregular in 28% and there was intraluminal material in 20%. The mean restenotic tissue symmetry ratio was 0.58 +/- 0.19. Heterogeneous and low scattering restenotic tissue was more frequent in focal (45.5% and 54.5%, respectively) than in diffuse (0 and 11.1%) and margin restenosis (0 and 0%) (P = .005 for heterogeneous, P = .03 for low scattering). Restenosis patients with unstable angina symptoms presented more frequently irregular lumen shape (60 vs 6.7%, P = .007). Stents implanted </=12 months ago had more frequently restenotic tissue with layered appearance (84.6% vs 16.7%, P = .003).
  
  
  CONCLUSIONS
  We demonstrate the ability of OCT to identify differential patterns of restenotic tissue after stenting. This information could help in understanding the mechanism of stent restenosis.
authors.affiliation: Thoraxcenter, Erasmus MC, Rotterdam 3015-CE, The Netherlands.
authors.forename: Nieves
authors.initials: N
authors.lastname: Gonzalo
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Serruys
authors.forename: Takayuki
authors.initials: T
authors.lastname: Okamura
authors.forename: Heleen M
authors.initials: HM
authors.lastname: van Beusekom
authors.forename: Hector M
authors.initials: HM
authors.lastname: Garcia-Garcia
authors.forename: Gijs
authors.initials: G
authors.lastname: van Soest
authors.forename: Wim
authors.initials: W
authors.lastname: van der Giessen
authors.forename: Evelyn
authors.initials: E
authors.lastname: Regar
mesh_terms: D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000175:diagnosis* / Q000473:pathology; D054855:Drug-Eluting Stents; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015607:Stents; D041623:Tomography, Optical Coherence