Diagnostic MethodsTroponin I as a specific marker of myocardial injury: from theory to clinical practice in the diagnosis of acute coronary syndromeBucciarelli-Ducci, Chiaraa; Rasile, Cristinaa; Proietti, Paolaa; Mancone, Massimoa; Volponi, Cristinaa; Vestri, Annaritab; Fedele, FrancescoaAuthor Information aDepartment of Cardiovascular and Respiratory Sciences bDepartment of Experimental Medicine and Pathology, University of Rome ‘La Sapienza’, Rome, Italy Correspondence and requests for reprints to Francesco Fedele, MD, Department of Cardiovascular and Respiratory Sciences, Policlinico Umberto I- University of Rome ‘La Sapienza’, Via del Policlinico 155, I-00161 Roma, Italy Tel: +39 06 49 97 90 21; fax: +39 06 49 97 90 60; e-mail: [email protected] Received 12 February 2004 Revised 21 July 2004 Accepted 1 October 2004 Coronary Artery Disease: December 2004 - Volume 15 - Issue 8 - p 499-504 Buy AbstractIn Brief 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. Troponins are the most specific markers of myocardial injury, but are not always synonymous of an ischemic mechanism of injury. Troponin increases may be observed in various clinical settings different than acute coronary syndrome and a misinterpretation of its rise may cause inappropriate diagnosis. © 2004 Lippincott Williams & Wilkins, Inc.