title: Serum protein profiles predict coronary artery disease in symptomatic patients referred for coronary angiography.
abstract: BACKGROUND
  More than a million diagnostic cardiac catheterizations are performed annually in the US for evaluation of coronary artery anatomy and the presence of atherosclerosis. Nearly half of these patients have no significant coronary lesions or do not require mechanical or surgical revascularization. Consequently, the ability to rule out clinically significant coronary artery disease (CAD) using low cost, low risk tests of serum biomarkers in even a small percentage of patients with normal coronary arteries could be highly beneficial.
  
  
  METHODS
  Serum from 359 symptomatic subjects referred for catheterization was interrogated for proteins involved in atherogenesis, atherosclerosis, and plaque vulnerability. Coronary angiography classified 150 patients without flow-limiting CAD who did not require percutaneous intervention (PCI) while 209 required coronary revascularization (stents, angioplasty, or coronary artery bypass graft surgery). Continuous variables were compared across the two patient groups for each analyte including calculation of false discovery rate (FDR ≤ 1%) and Q value (P value for statistical significance adjusted to ≤ 0.01).
  
  
  RESULTS
  Significant differences were detected in circulating proteins from patients requiring revascularization including increased apolipoprotein B100 (APO-B100), C-reactive protein (CRP), fibrinogen, vascular cell adhesion molecule 1 (VCAM-1), myeloperoxidase (MPO), resistin, osteopontin, interleukin (IL)-1β, IL-6, IL-10 and N-terminal fragment protein precursor brain natriuretic peptide (NT-pBNP) and decreased apolipoprotein A1 (APO-A1). Biomarker classification signatures comprising up to 5 analytes were identified using a tunable scoring function trained against 239 samples and validated with 120 additional samples. A total of 14 overlapping signatures classified patients without significant coronary disease (38% to 59% specificity) while maintaining 95% sensitivity for patients requiring revascularization. Osteopontin (14 times) and resistin (10 times) were most frequently represented among these diagnostic signatures. The most efficacious protein signature in validation studies comprised osteopontin (OPN), resistin, matrix metalloproteinase 7 (MMP7) and interferon γ (IFNγ) as a four-marker panel while the addition of either CRP or adiponectin (ACRP-30) yielded comparable results in five protein signatures.
  
  
  CONCLUSIONS
  Proteins in the serum of CAD patients predominantly reflected (1) a positive acute phase, inflammatory response and (2) alterations in lipid metabolism, transport, peroxidation and accumulation. There were surprisingly few indicators of growth factor activation or extracellular matrix remodeling in the serum of CAD patients except for elevated OPN. These data suggest that many symptomatic patients without significant CAD could be identified by a targeted multiplex serum protein test without cardiac catheterization thereby eliminating exposure to ionizing radiation and decreasing the economic burden of angiographic testing for these patients.
authors.affiliation: University of Pittsburgh, Department of Pathology, 5230 Centre Avenue, Pittsburgh, PA 15232, USA. laframboisewa@upmc.edu
authors.forename: William A
authors.initials: WA
authors.lastname: LaFramboise
authors.forename: Rajiv
authors.initials: R
authors.lastname: Dhir
authors.forename: Lori A
authors.initials: LA
authors.lastname: Kelly
authors.forename: Patricia
authors.initials: P
authors.lastname: Petrosko
authors.forename: John M
authors.initials: JM
authors.lastname: Krill-Burger
authors.forename: Christin M
authors.initials: CM
authors.lastname: Sciulli
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Lyons-Weiler
authors.forename: Uma R
authors.initials: UR
authors.lastname: Chandran
authors.forename: Aleksey
authors.initials: A
authors.lastname: Lomakin
authors.forename: Robert V
authors.initials: RV
authors.lastname: Masterson
authors.forename: Oscar C
authors.initials: OC
authors.lastname: Marroquin
authors.forename: Suresh R
authors.initials: SR
authors.lastname: Mulukutla
authors.forename: Dennis M
authors.initials: DM
authors.lastname: McNamara
mesh_terms: D001798:Blood Proteins / Q000032:analysis*; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000097:blood* / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests
chemical_list: D001798:Blood Proteins