title: Detection of vulnerable coronary plaques by color fluorescent angioscopy.
abstract: OBJECTIVE
  This study was carried out to detect vulnerable coronary plaques by color fluorescent angioscopy.
  
  
  BACKGROUND
  Collagen fibers (CFs) mainly provide mechanical support to coronary plaques. Oxidized low-density lipoprotein (Ox-LDL) induces macrophage proliferation, which in turn destroy CFs while accumulating lipids. As such, demonstration of the absence of CFs, deposition of lipids, and the Ox-LDL may suggest plaque instability.
  
  
  METHODS
  Fluorescence of the major components of the atherosclerotic plaques was examined by fluorescent microscopy using a 345-nm band-pass filter and 420-nm band-absorption filter (A-imaging). Fluorescence of Ox-LDL was examined using a 470-nm band-pass filter and 515-nm band-absorption filter (B-imaging) and Evans blue dye as an indicator. Fluorescence in 57 excised human coronary plaques was examined by A-imaging color fluorescent angioscopy. Oxidized LDL in 31 excised coronary plaques and in 12 plaques of 7 patients was investigated by B-imaging color fluorescent angioscopy.
  
  
  RESULTS
  Collagen I, collagen IV, and calcium exhibited blue, light blue, and white autofluorescence, respectively. In the presence of beta-carotene which coexists with lipids in the vascular wall, collagen I and IV exhibited green, collagen III and V white, cholesterol yellow, cholesteryl esters orange fluorescence. Oxidized LDL exhibited reddish brown fluorescence in the presence of Evans blue dye. Therefore, coronary plaques exhibited blue, green, white-to-light blue, or yellow-to-orange fluorescence based on plaque composition. Histological examination revealed abundant CFs without lipids in blue plaques; CFs and lipids in green plaques; meager CFs and abundant lipids in white-to-light blue plaques; and the absence of CFs and deposition of lipids, calcium, and macrophage foam cells in the thin fibrous cap in yellow-to-orange plaques, indicating that the yellow-to-orange plaques were most vulnerable. Reddish brown fluorescence characteristic of Ox-LDL was observed in excised coronary plaques, as also in patients.
  
  
  CONCLUSIONS
  Color fluorescent angioscopy provides objective information related to coronary plaque composition and may help identify unstable plaques.
authors.affiliation: Japan Foundation for Cardiovascular Research, Funabashi and Tokyo, Japan. uchiy@ta2.so-net.ne.jp
authors.forename: Yasumi
authors.initials: Y
authors.lastname: Uchida
authors.forename: Yasuto
authors.initials: Y
authors.lastname: Uchida
authors.forename: Seiji
authors.initials: S
authors.lastname: Kawai
authors.forename: Ryohei
authors.initials: R
authors.lastname: Kanamaru
authors.forename: Yukou
authors.initials: Y
authors.lastname: Sugiyama
authors.forename: Takanobu
authors.initials: T
authors.lastname: Tomaru
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Maezawa
authors.forename: Noriaki
authors.initials: N
authors.lastname: Kameda
mesh_terms: D000368:Aged; D017546:Angioscopy; D001344:Autopsy; D015415:Biomarkers / Q000032:analysis; D002118:Calcium / Q000032:analysis; D002784:Cholesterol / Q000032:analysis; D003094:Collagen / Q000032:analysis; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D003331:Coronary Vessels / Q000737:chemistry* / Q000473:pathology; D018450:Disease Progression; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D008077:Lipoproteins, LDL / Q000032:analysis; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D011237:Predictive Value of Tests; D019207:beta Carotene / Q000032:analysis
chemical_list: D015415:Biomarkers; D005456:Fluorescent Dyes; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D019207:beta Carotene; D003094:Collagen; D002784:Cholesterol; D002118:Calcium