title: Coronary plaque structural stress is associated with plaque composition and subtype and higher in acute coronary syndrome: the BEACON I (Biomechanical Evaluation of Atheromatous Coronary Arteries) study.
abstract: BACKGROUND
  Atherosclerotic plaques underlying most myocardial infarctions have thin fibrous caps and large necrotic cores; however, these features alone do not reliably identify plaques that rupture. Rupture occurs when plaque structural stress (PSS) exceeds mechanical strength. We examined whether PSS could be calculated in vivo based on virtual histology (VH) intravascular ultrasound and whether PSS varied according to plaque composition, subtype, or clinical presentation.
  
  
  RESULTS
  A total of 4429 VH intravascular ultrasound frames from 53 patients were analyzed, identifying 99 584 individual plaque components. PSS was calculated by finite element analysis in whole vessels, in individual plaques, and in higher-risk regions (plaque burden ≥70%, mean luminal area ≤4 mm(2), noncalcified VH-defined thin-cap fibroatheroma). Plaque components including total area/arc of calcification (R(2)=0.33; P<0.001 and R(2)=0.28; P<0.001) and necrotic core (R(2)=0.18; P<0.001 and R(2)=0.15; P<0.001) showed complex, nonlinear relationships with PSS. PSS was higher in noncalcified VH-defined thin-cap fibroatheroma compared with thick-cap fibroatheromas (median [Q1-Q3], 8.44 [6.97-10.64] versus 7.63 [6.37-9.68]; P=0.002). PSS was also higher in patients with an acute coronary syndrome, where mean luminal area ≤4 mm(2) (8.24 [7.06-9.93] versus 7.72 [6.33-9.34]; P=0.03), plaque burden ≥70% (9.18 [7.44-10.88] versus 7.93 [6.16-9.46]; P=0.02), and in noncalcified VH-defined thin-cap fibroatheroma (9.23 [7.33-11.44] versus 7.65 [6.45-8.62]; P=0.02). Finally, PSS increased the positive predictive value for VH intravascular ultrasound to identify clinical presentation.
  
  
  CONCLUSIONS
  Finite element analysis modeling demonstrates that structural stress is highly variable within plaques, with increased PSS associated with plaque composition, subtype, and higher-risk regions in patients with acute coronary syndrome. PSS may represent a novel tool to analyze the dynamic behavior of coronary plaques with the potential to improve prediction of plaque rupture.
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.).
authors.forename: Zhongzhao
authors.initials: Z
authors.lastname: Teng
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.).
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Brown
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.).
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Calvert
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.).
authors.forename: Richard A
authors.initials: RA
authors.lastname: Parker
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.).
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Obaid
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.).
authors.forename: Yuan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.).
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Hoole
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.).
authors.forename: Nick E J
authors.initials: NE
authors.lastname: West
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.).
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Gillard
authors.affiliation: From the Department of Radiology (Z.T., Y.H., J.H.G.), Department of Engineering (Z.T.), Division of Cardiovascular Medicine (A.J.B., P.A.C., D.R.O., M.R.B.), and Centre for Applied Medical Statistics, University of Cambridge, Cambridge, UK (R.A.P.); and Department of Interventional Cardiology, Papworth Hospital NHS Trust, Cambridge, UK (S.P.H., N.E.J.W.). mrb@mole.bio.cam.ac.uk.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Bennett
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications / Q000000981:diagnostic imaging*; D002114:Calcinosis / Q000150:complications / Q000000981:diagnostic imaging; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000150:complications / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013314:Stress, Mechanical; D018084:Ultrasonography, Interventional / Q000379:methods
keywords: arteriosclerosis; coronary disease; ultrasonics