title: Troponin I as a specific marker of myocardial injury: from theory to clinical practice in the diagnosis of acute coronary syndrome.
abstract: OBJECTIVE
  To assess the diagnostic accuracy of troponin I (TnI) elevation in patients with acute coronary syndrome (ACS) in the emergency department (ED).
  
  
  METHODS
  We retrospectively studied 166 patients with elevated TnI and electrocardiographic (ECG) change consistent with non-ST-segment elevation myocardial infarction. They were transferred from the ED to our coronary care unit (CCU) to undergo coronary angiography.
  
  
  RESULTS
  Significant coronary stenosis were identified in 101 (61%) of patients. The other 65 patients were found to have different cardiac diseases (n=52) and in 13 patients diagnoses were not even related to the cardiovascular system. Wall motion abnormalities were assessed by echocardiographic wall motion score index (WMSI). Positive predictive value (PPV) of TnI varied from 53 to 65% for higher progressive values of the biomarker. The following PPVs were then calculated: PPV(TnI+CK-MB)=64%; PPV(TnI+WMSI)=72%, PPV(TnI+CK-MB+WMSI)=74%.
  
  
  CONCLUSIONS
  Abnormal values of TnI were detected in a variety of diseases not related to ACS. Even if troponin release indicates myocardial injury, it is not always synonymous with infarction or ischemia. A misinterpretation of TnI elevation may give rise to a diagnostic dilemma and cause unnecessary morbidity. An integration of biomarkers (TnI and CK-MB), ECG and WMSI will help identify false-positive ACS patients and avoid inappropriate admissions to CCU.
authors.affiliation: Department of Cardiovascular and Respiratory Sciences, University of Rome La Sapienza, Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Bucciarelli-Ducci
authors.forename: Cristina
authors.initials: C
authors.lastname: Rasile
authors.forename: Paola
authors.initials: P
authors.lastname: Proietti
authors.forename: Massimo
authors.initials: M
authors.lastname: Mancone
authors.forename: Cristina
authors.initials: C
authors.lastname: Volponi
authors.forename: Annarita
authors.initials: A
authors.lastname: Vestri
authors.forename: Francesco
authors.initials: F
authors.lastname: Fedele
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D011379:Prognosis; D012372:ROC Curve; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I