title: Diagnosis of unstable angina pectoris has declined markedly with the advent of more sensitive troponin assays.
abstract: BACKGROUND
  Since the arrival of the universal definition of myocardial infarction more sensitive troponin assays have been developed. How these occurrences have influenced the proportions and clinical features of the components of acute coronary syndrome have not been studied prospectively in unselected hospital patients.
  
  
  METHODS
  During 2010 we evaluated all patients in whom cardiac troponin I had been measured at a single university hospital. The diagnosis of acute myocardial infarction (ST-elevation myocardial infarction [STEMI] or non-ST-elevation myocardial infarction [NSTEMI]) was established in cases of a rise and/or fall of cardiac troponin I together with cardiac ischemic features. Patients with unstable chest discomfort and cardiac troponin I values below the decision limit of myocardial infarction were diagnosed as having unstable angina pectoris. The definition of acute coronary syndrome included unstable angina pectoris, NSTEMI, and STEMI. Mortality data were obtained from the Danish Civil Personal Registration System.
  
  
  RESULTS
  Of 3762 consecutive patients, 516 had acute coronary syndrome. Unstable angina pectoris was present in 7%, NSTEMI in 67%, and STEMI in 26%. The NSTEMI patients were older, more frequently women, and had more comorbidities than patients with unstable angina pectoris and STEMI. At median follow-up of 3.2 years 195 patients had died: 14% of unstable angina pectoris, 45% of NSTEMI, and 25% of STEMI patients. Age-adjusted log-rank statistics revealed differences in mortality: NSTEMI vs unstable angina pectoris (P = .0091) and NSTEMI vs STEMI (P = .0045).
  
  
  CONCLUSIONS
  The application of the universal definition together with the use of a contemporary troponin assay seems to have reduced the proportion of patients with unstable angina pectoris to the benefit of patients with NSTEMI. Despite this, NSTEMI patients have a sustained higher mortality than patients with STEMI.
authors.affiliation: Department of Cardiology, Odense University Hospital, Odense, Denmark.
authors.forename: Maria
authors.initials: M
authors.lastname: D'Souza
authors.affiliation: Department of Cardiology, Odense University Hospital, Odense, Denmark.
authors.forename: Laura
authors.initials: L
authors.lastname: Sarkisian
authors.affiliation: Department of Cardiology, Odense University Hospital, Odense, Denmark.
authors.forename: Lotte
authors.initials: L
authors.lastname: Saaby
authors.affiliation: Department of Cardiology, Odense University Hospital, Odense, Denmark.
authors.forename: Tina S
authors.initials: TS
authors.lastname: Poulsen
authors.affiliation: Department of Nuclear Medicine, Odense University Hospital and Center of Health Economics Research, Odense, Denmark.
authors.forename: Oke
authors.initials: O
authors.lastname: Gerke
authors.affiliation: Department of Cardiology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Torben B
authors.initials: TB
authors.lastname: Larsen
authors.affiliation: Department of Cardiology, Odense University Hospital, Odense, Denmark.
authors.forename: Axel C P
authors.initials: AC
authors.lastname: Diederichsen
authors.affiliation: Department of Cardiology, Odense University Hospital, Odense, Denmark.
authors.forename: Nikolaj
authors.initials: N
authors.lastname: Jangaard
authors.affiliation: Department of Cardiology, Odense University Hospital, Odense, Denmark.
authors.forename: Søren Z
authors.initials: SZ
authors.lastname: Diederichsen
authors.affiliation: Department of Cardiology, Odense University Hospital, Odense, Denmark.
authors.forename: Susanne
authors.initials: S
authors.lastname: Hosbond
authors.affiliation: Department of Cardiology, Hvidovre Hospital, Copenhagen, Denmark.
authors.forename: Jens
authors.initials: J
authors.lastname: Hove
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Thygesen
authors.affiliation: Department of Cardiology, Odense University Hospital, Odense, Denmark. Electronic address: Hans.mickley@rsyd.dk.
authors.forename: Hans
authors.initials: H
authors.lastname: Mickley
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D003718:Denmark / Q000453:epidemiology; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality; D011446:Prospective Studies; D015996:Survival Rate; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I
keywords: Acute coronary syndrome; Mortality; Myocardial infarction; Troponin; Unstable angina pectoris