title: New definition of myocardial infarction: impact on long-term mortality.
abstract: BACKGROUND
  The use of cardiac troponin allows the identification of additional patients developing myocardial necrosis during an acute coronary syndrome. Novel guidelines of European and American cardiac societies recommend labeling these events as myocardial infarction. Our study evaluated the long-term mortality in the group of patients with non-ST segment elevation myocardial infarction not meeting the older World Health Organization (WHO) criteria (creatine phosphokinase) but additionally identified by the novel definition of myocardial infarction.
  
  
  METHODS
  This cohort study included 1024 consecutive patients with non-ST segment elevation acute coronary syndrome classified into "unstable angina," myocardial infarction according to the WHO definition ("WHO criteria"), and myocardial infarction additionally identified by the novel definition ("additional criteria"). All patients were treated with an early invasive strategy. The primary end point was all-cause mortality during follow-up of up to 36 months.
  
  
  RESULTS
  During long-term follow-up (median 16 months, interquartile range 6-29 months), 67 deaths occurred. Kaplan-Meier analysis showed cumulative 3-year mortality rates of 5.6% in patients with "unstable angina," 9.1% in patients identified by "WHO criteria," and 17.5% in patients identified by "additional criteria" (P <.001). Cox regression analysis confirmed the "additional criteria" as a significant predictor of mortality (hazard ratio 3.1; 95% confidence interval, 1.9-5.0; P <.001).
  
  
  CONCLUSIONS
  The new definition of myocardial infarction based on cardiac troponin testing identifies a high-risk group of additional patients with acute coronary syndrome that is, therefore, appropriately classified as myocardial infarction. In fact, long-term mortality in "additional criteria" patients is higher than in "WHO criteria" patients.
authors.affiliation: Herz-Zentrum, Bad Krozingen, Germany.
authors.forename: Willibald
authors.initials: W
authors.lastname: Hochholzer
authors.forename: Heinz J
authors.initials: HJ
authors.lastname: Buettner
authors.forename: Dietmar
authors.initials: D
authors.lastname: Trenk
authors.forename: Kirsten
authors.initials: K
authors.lastname: Laule
authors.forename: Michael
authors.initials: M
authors.lastname: Christ
authors.forename: Franz-Josef
authors.initials: FJ
authors.lastname: Neumann
authors.forename: Christian
authors.initials: C
authors.lastname: Mueller
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000175:diagnosis; D015331:Cohort Studies; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000145:classification* / Q000401:mortality*; D019210:Troponin I / Q000097:blood
chemical_list: D019210:Troponin I; D003402:Creatine Kinase