title: Incremental Prognostic Value of Quantified Vulnerable Plaque by Cardiac Computed Tomography: A Pilot Study.
abstract: BACKGROUND
  Coronary computed tomography (CT) angiography (CCTA) has the ability to detect, characterize, and quantify atherosclerotic plaques. The aim of our study was to evaluate the prognostic power of CCTA-quantified plaque subtypes.
  
  
  METHODS
  A total of 36 patients with adverse events and 36 Morise score-matched patients who remained event free on follow-up were identified. Using CCTA images, plaque subtype volumes in the major epicardial arteries were analyzed using predetermined attenuation ranges in Hounsfield units (HU): 1 to 30 HU (low attenuating), 31 to 70 HU (intermediate attenuating), 71 to 150 HU (high attenuating), and mean coronary lumen+2 SD to 1000 HU (calcified). Each epicardial artery was divided into proximal, mid, and distal segments, and plaque volumes were normalized for arterial segment length.
  
  
  RESULTS
  The baseline characteristics of the 2 cohorts were similar. Low-attenuation and intermediate-attenuation plaque volumes were greater in the proximal segments as well as in the entire length in the adverse event compared with the event-free group. High-attenuation plaque volume was increased only in the proximal segments in the adverse event group. There was no difference in the volume of calcified plaque between the 2 groups. The log rank test using a cutoff of 3.99 mm/mm for combined intermediate and low plaque volume showed more adverse events in patients with a plaque volume of ≥3.99 mm/mm.
  
  
  CONCLUSIONS
  Adverse events appear to be associated with greater volumes of low-attenuation and intermediate-attenuation plaques that reflect lipid and fibrous atherosclerosis. The difference between the 2 groups is most apparent in the proximal epicardial arteries.
authors.affiliation: *Department of Medicine (Cardiology), University of Ottawa Heart Institute Departments of ‡Medicine †Radiology, University of Ottawa, ON, Canada.
authors.forename: Girish
authors.initials: G
authors.lastname: Dwivedi
authors.forename: Yingwei
authors.initials: Y
authors.lastname: Liu
authors.forename: Shrankhala
authors.initials: S
authors.lastname: Tewari
authors.forename: Joao
authors.initials: J
authors.lastname: Inacio
authors.forename: Matthieu
authors.initials: M
authors.lastname: Pelletier-Galarneau
authors.forename: Benjamin J W
authors.initials: BJ
authors.lastname: Chow
mesh_terms: D000368:Aged; D000072226:Computed Tomography Angiography / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging*; D011379:Prognosis