title: Autoantibodies against apolipoprotein A-1 and phosphorylcholine for diagnosis of non-ST-segment elevation myocardial infarction.
abstract: OBJECTIVE
  To explore the diagnostic accuracies of anti-apolipoproteinA-1 (anti-ApoA-1) IgG and anti-phosphorylcholine (anti-PC) IgM alone, expressed as a ratio (anti-ApoA-1 IgG/anti-PC IgM), and combined with the Thrombolysis In Myocardial Infarction (TIMI) score for non-ST-segment elevation myocardial infarction (NSTEMI) (NSTEMI-TIMI score) to create a new diagnostic algorithm - the Clinical Autoantibody Ratio (CABR) score - for the diagnosis of NSTEMI and subsequent cardiac troponin I (cTnI) elevation in patients with acute chest pain (ACP).
  
  
  METHODS
  In this single-centre prospective study, 138 patients presented at the emergency department with ACP without ST-segment elevation myocardial infarction. Anti-ApoA-1 IgG and anti-PC IgM were assessed by enzyme-linked immunosorbent assay on admission. Post hoc determination of the CABR score cut-off was performed by receiver operating characteristics analyses.
  
  
  RESULTS
  The adjudicated final diagnosis was NSTEMI in 17% (24/138) of patients. Both autoantibodies alone were found to be significant predictors of NSTEMI diagnosis, but the CABR score had the best diagnostic accuracy [area under the curve (AUC): 0.88; 95% confidence interval (CI): 0.82-0.95]. At the optimal cut-off of 3.3, the CABR score negative predictive value (NPV) was 97% (95% CI: 90-99). Logistic regression analysis showed that a CABR score >3.3 increased the risk of subsequent NSTEMI diagnosis 19-fold (odds ratio: 18.7; 95% CI: 5.2-67.3). For subsequent cTnI positivity, only anti-ApoA-1 IgG and CABR score displayed adequate predictive accuracies with AUCs of 0.80 (95% CI: 0.68-0.91) and 0.82 (95% CI: 0.70-0.94), respectively; the NPVs were 95% (95% CI: 90-98) and 99% (95% CI: 94-100), respectively.
  
  
  CONCLUSIONS
  The CABR score, derived from adding the anti-ApoA-1 IgG/anti-PC IgM ratio to the NSTEMI-TIMI score, could be a useful measure to rule out NSTEMI in patients presenting with ACP at the emergency department without electrocardiographic changes.
authors: Division of Cardiology, Department of Internal Medicine, Geneva University Hospitals, Geneva, Switzerland.
authors: P-F
authors: PF
authors: Keller
authors: S
authors: S
authors: Pagano
authors: P
authors: P
authors: Roux-Lombard
authors: P
authors: P
authors: Sigaud
authors: O T
authors: OT
authors: Rutschmann
authors: F
authors: F
authors: Mach
authors: D
authors: D
authors: Hochstrasser
authors: N
authors: N
authors: Vuilleumier
mesh_terms: D000368:Aged; D000465:Algorithms; D016632:Apolipoprotein A-I / Q000276:immunology*; D019540:Area Under Curve; D001323:Autoantibodies / Q000097:blood*; D016001:Confidence Intervals; D004562:Electrocardiography / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology; D016017:Odds Ratio; D010767:Phosphorylcholine / Q000276:immunology*; D011237:Predictive Value of Tests; D015912:Thrombolytic Therapy / Q000379:methods*
chemical_list: D016632:Apolipoprotein A-I; D001323:Autoantibodies; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010767:Phosphorylcholine