title: Impact of changing definitions for myocardial infarction: a report from the AMIS registry.
abstract: BACKGROUND
  To assess the impact of the new definitions of myocardial infarction, we retrospectively analyzed 9190 patients from 63 hospitals with reported peak troponin values included between 2001 and 2007 in the Swiss AMIS (Acute Myocardial Infarction in Switzerland) Plus registry.
  
  
  METHODS
  Patients were classified as belonging to the "classic" myocardial infarction group (peak total CK or CK-MB above the upper limit of normal, or troponin T [TnT] >0.1 microg/L or troponin I [TnI] >0.1-0.8 microg/L [depending on the assay]) or "new" myocardial infarction group (TnT >0.01 microg/L or TnI >0.01-0.07 microg/L).
  
  
  RESULTS
  There were 489 patients in the "new" group who were similar to the 8701 "classic" patients in terms of age, sex, and prevalence of both diabetes and renal failure, but more frequently had a history of prior coronary artery disease, hypertension, and hyperlipidemia. At admission, they less frequently had ST elevation on their electrocardiogram, were more frequently in Killip class I, and received less primary percutaneous coronary intervention. Hospital mortality was 3.5% in the "new" and 6.7% in the "classic" myocardial infarction group (P=.004). In a subset of patients with a longer follow-up, mortality at 3 and 12 months was 1% and 5.6%, respectively, for "new" and 1.6% and 4%, respectively, for "classic" myocardial infarction (NS).
  
  
  CONCLUSIONS
  Patients with minimal elevation of serum troponin have smaller infarctions, less aggressive treatment, fewer early complications, and a better early prognosis than patients with higher serum biomarker levels. After discharge, however, their prognosis currently appears no different from that of patients with a "classic" myocardial infarction event.
authors.affiliation: Cardiovascular Department, La Tour Hospital, Geneva, Switzerland. philip.urban@latour.ch
authors.forename: Philip
authors.initials: P
authors.lastname: Urban
authors.forename: Dragana
authors.initials: D
authors.lastname: Radovanovic
authors.forename: Paul
authors.initials: P
authors.lastname: Erne
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Stauffer
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pedrazzini
authors.forename: Stephan
authors.initials: S
authors.lastname: Windecker
authors.forename: Osmund
authors.initials: O
authors.lastname: Bertel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000145:classification* / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D013557:Switzerland / Q000453:epidemiology