title: Troponin levels within the normal range and probability of inducible myocardial ischemia and coronary events in patients with acute chest pain.
abstract: OBJECTIVE
  Patients with suspected acute coronary syndromes and negative cardiac troponin (cTn) levels are deemed at low risk. Our aim was to assess the effect of cTn levels on the frequency of inducible myocardial ischemia and subsequent coronary events in patients with acute chest pain and cTn levels within the normal range.
  
  
  METHODS
  We evaluated 4474 patients with suspected acute coronary syndromes, nondiagnostic electrocardiograms and serial cTnI levels below the diagnostic threshold for myocardial necrosis using a conventional or a sensitive cTnI assay. The end points were the probability of inducible myocardial ischemia and coronary events (i.e., coronary death, myocardial infarction or coronary revascularization within 3 months).
  
  
  RESULTS
  The probability of inducible myocardial ischemia was significantly higher in patients with detectable peak cTnI levels (25%) than in those with undetectable concentrations (14.6%, p<0.001). These results were consistent regardless of the type of cTnI assay, the type of stress testing modality, or the timing for cTnI measurement, and remained significant after multivariate adjustment (odds ratio [OR] 1.47, 95% confidence interval [CI] 1.21-1.79, p<0.001). The rate of coronary events at 3 months was also significantly higher in patients with detectable cTnI levels (adjusted OR 2.08, 95% CI 1.64-2.64, p<0.001).
  
  
  CONCLUSIONS
  Higher cTnI levels within the normal range were associated with a significantly increased probability of inducible myocardial ischemia and coronary events in patients with suspected acute coronary syndromes and seemingly negative cTnI.
authors.affiliation: Servicio de Cardiología, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain. Electronic address: alberto.bouzas.mosquera@sergas.es.
authors.forename: Alberto
authors.initials: A
authors.lastname: Bouzas-Mosquera
authors.affiliation: Servicio de Cardiología, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Peteiro
authors.affiliation: Departamento de Tecnologías de la Información, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Broullón
authors.affiliation: Laboratorio de Análisis Clínicos, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain.
authors.forename: Ignacio P
authors.initials: IP
authors.lastname: Constanso
authors.affiliation: Servicio de Cardiología, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Rodríguez-Garrido
authors.affiliation: Servicio de Cardiología, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain.
authors.forename: Dolores
authors.initials: D
authors.lastname: Martínez
authors.affiliation: Servicio de Cardiología, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Yáñez
authors.affiliation: Laboratorio de Análisis Clínicos, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain.
authors.forename: Hildegart
authors.initials: H
authors.lastname: Bescos
authors.affiliation: Servicio de Cardiología, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain.
authors.forename: Nemesio
authors.initials: N
authors.lastname: Álvarez-García
authors.affiliation: Servicio de Cardiología, Complexo Hospitalario Universitario A Coruña, Instituto de Investigación Biomédica de A Coruña (INIBIC), A Coruña, Spain.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Vázquez-Rodríguez
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood / Q000150:complications / Q000453:epidemiology; D000368:Aged; D002637:Chest Pain / Q000097:blood* / Q000209:etiology; D003327:Coronary Disease / Q000401:mortality; D016208:Databases, Factual; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology*; D017202:Myocardial Ischemia / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D009204:Myocardial Revascularization / Q000706:statistics & numerical data*; D018570:Risk Assessment; D019210:Troponin I / Q000097:blood*
chemical_list: D019210:Troponin I
keywords: Acute coronary syndrome; Chest pain; Exercise testing; Troponin