title: A Plaque Disruption Index Identifies Patients with Non-STE-Type 1 Myocardial Infarction within 24 Hours of Troponin Positivity.
abstract: BACKGROUND
  Markers of plaque destabilization and disruption may have a role in identifying non-STE- type 1 Myocardial Infarction in patients presenting with troponin elevation. We hypothesized that a plaque disruption index (PDI) derived from multiple biomarkers and measured within 24 hours from the first detectable troponin in patients with acute non-STE- type 1 MI (NSTEMI-A) will confirm the diagnosis and identify these patients with higher specificity when compared to individual markers and coronary angiography.
  
  
  METHODS
  We examined 4 biomarkers of plaque destabilization and disruption: myeloperoxidase (MPO), high-sensitivity interleukin-6, myeloid-related protein 8/14 (MRP8/14) and pregnancy-associated plasma protein-A (PAPP-A) in 83 consecutive patients in 4 groups: stable non-obstructive coronary artery disease (CAD), stable obstructive CAD, NSTEMI-A (enrolled within 24 hours of troponin positivity), and NSTEMI-L (Late presentation NSTEMI, enrolled beyond the 24 hour limit). The PDI was calculated and the patients' coronary angiograms were reviewed for evidence of plaque disruption. The diagnostic performance of the PDI and angiography were compared.
  
  
  RESULTS
  Compared to other biomarkers, MPO had the highest specificity (83%) for NSTEMI-A diagnosis (P<0.05). The PDI computed from PAPP-A, MRP8/14 and MPO was higher in NSTEMI-A patients compared to the other three groups (p<0.001) and had the highest diagnostic specificity (87%) with 79% sensitivity and 86% accuracy, which were higher compared to those obtained with MPO, but did not reach statistical significance (P>0.05 for all comparisons). The PDI had higher specificity and accuracy for NSTEMI-A diagnosis compared to coronary angiography (P<0.05).
  
  
  CONCLUSIONS
  A PDI measured within 24 hour of troponin positivity has potential to identify subjects with acute Non-ST-elevation type 1 MI. Additional evidence using other marker combinations and investigation in a sufficiently large non-selected cohort is warranted to establish the diagnostic accuracy of the PDI and its potential role in differentiating type 1 and type 2 MI in patients presenting with troponin elevation of uncertain etiology.
authors.affiliation: Department of Clinical Sciences, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
authors.forename: Maha A
authors.initials: MA
authors.lastname: Al-Mohaissen
authors.affiliation: Department of Medicine, Division of Cardiology, St. Paul's Hospital and the University of British Columbia, Vancouver, BC, Canada.
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Carere
authors.affiliation: Department of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: G B John
authors.initials: GB
authors.lastname: Mancini
authors.affiliation: Department of Medicine, Division of Cardiology, St. Paul's Hospital and the University of British Columbia, Vancouver, BC, Canada.
authors.forename: Karin H
authors.initials: KH
authors.lastname: Humphries
authors.affiliation: Centre for Heart Lung Innovation, St. Paul's Hospital and University of British Columbia, Vancouver, BC, Canada.
authors.forename: Beth A
authors.initials: BA
authors.lastname: Whalen
authors.affiliation: Centre for Health Evaluation and Outcome Sciences, St. Paul's Hospital and University of British Columbia, Vancouver, BC, Canada.
authors.forename: Terry
authors.initials: T
authors.lastname: Lee
authors.affiliation: Department of Emergency Medicine, St. Paul's Hospital and the University of British Columbia, Vancouver, BC, Canada.
authors.forename: Frank X
authors.initials: FX
authors.lastname: Scheuermeyer
authors.affiliation: Department of Medicine, Division of Cardiology, St. Paul's Hospital and the University of British Columbia, Vancouver, BC, Canada.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Ignaszewski
mesh_terms: D000368:Aged; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D002135:Calcium-Binding Proteins / Q000097:blood; D040501:Calgranulin A / Q000097:blood; D017023:Coronary Angiography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000000981:diagnostic imaging; D009195:Peroxidase / Q000097:blood; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis; D012372:ROC Curve; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D002135:Calcium-Binding Proteins; D040501:Calgranulin A; D015850:Interleukin-6; C462950:S100A14 protein, human; D019210:Troponin I; D009195:Peroxidase; D011266:Pregnancy-Associated Plasma Protein-A