title: Interleukin-6 as a predictor of cardiovascular events in troponin-negative non-ST elevation acute coronary syndrome patients.
abstract: OBJECTIVE
  Risk stratification in acute coronary syndrome without ST-segment elevation (NSTE-ACS) and troponin-negative remains a challenge. We evaluated the value of interleukin-6 (IL-6) and amino-terminal pro-B-type natriuretic peptide (NT-proBNP) in the prognosis assessment of low-moderate risk NSTE-ACS and troponin-negative, and whether these biomarkers could improve the predictive performance of the established thrombolysis in myocardial infarction (TIMI) risk score.
  
  
  METHODS
  A total of 212 low-moderate risk patients with NSTE-ACS and troponin-negative were prospectively studied. Clinical follow up at 6 months was performed for adverse endpoints.
  
  
  RESULTS
  A total of 28 patients (13.5%) presented adverse clinical events. Those with adverse clinical events were associated with higher levels of IL-6 [8.58 (5.13-20.95) ng/l vs. 6.12 (4.16-9.14) ng/l, p = 0.043] and NT-proBNP [275.3 (108.6-548.2) ng/l vs. 126.8 (55.97-430.20) ng/l, p = 0.046]. In moderate risk group, we observed a higher event rate in patients with troponin-negative but elevated levels of IL-6 (p = 0.024). Only elevated IL-6 (> 12.40 ng/l) was an independent predictor of adverse outcomes [hazard ratios: 3.62, 95% confidence interval (CI) 1.69-7.75, p = 0.001]. The addition of IL-6 and history of ischaemic heart disease (IHD) to TIMI risk score significantly improved both the discrimination (integrated discrimination improvement, p = 0.003) and reclassification (Clinical Net reclassification improvement, p = 0.010) of the model for adverse events.
  
  
  CONCLUSIONS
  Interleukin-6 is an independent predictor of adverse events in low-moderate risk patients with NSTE-ACS and troponin-negative. Its use identifies a higher risk population in moderate-risk patients. This provides together with history of IHD a better discrimination and reclassification beyond that achieved with clinical risk variables from TIMI risk score in these patients.
authors.affiliation: Department of Clinical Analysis, University Hospital Virgen de la Arrixaca, Murcia, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: García-Salas
authors.forename: A
authors.initials: A
authors.lastname: Tello-Montoliu
authors.forename: S
authors.initials: S
authors.lastname: Manzano-Fernández
authors.forename: T
authors.initials: T
authors.lastname: Casas-Pina
authors.forename: A
authors.initials: A
authors.lastname: López-Cuenca
authors.forename: P
authors.initials: P
authors.lastname: Pérez-Berbel
authors.forename: C
authors.initials: C
authors.lastname: Puche-Morenilla
authors.forename: P
authors.initials: P
authors.lastname: Martínez-Hernández
authors.forename: M
authors.initials: M
authors.lastname: Valdés
authors.forename: F
authors.initials: F
authors.lastname: Marín
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis*; D000787:Angina Pectoris / Q000209:etiology; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000209:etiology; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000517:prevention & control; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D020097:Natriuretic Peptide, Brain / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D011379:Prognosis; D011446:Prospective Studies; D012008:Recurrence; D018570:Risk Assessment / Q000379:methods; D014336:Troponin / Q000378:metabolism
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D010446:Peptide Fragments; D014336:Troponin; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain