Elevation of serum cardiac troponin I in noncardiac and cardiac diseases other than acute coronary syndromes

This study evaluated the role of serum cardiac troponin I as a biochemical marker for the diagnosis of acute coronary syndromes in the presence of non cardiac diseases. Diagnostic characteristics were examined in 102 consecuti ve patients who were found to have serum cardiac troponin I levels higher t han the upper reference limit of 0.6 ng/mL. Of 102 patients with cardiac tr oponin I levels of >0.6 ng/mL, 35 did not have the final diagnoses of acute coronary syndromes (myocardial infarction or unstable angina) but had vari ous other final diagnoses, including nonischemic dilated cardiomyopathy, mu scular disorders, central nervous system disorders, HIV disease, chronic re nal failure, sepsis, lung diseases, and endocrine disorders. The mean value of serum cardiac troponin I in the patients with diseases other than acute coronary syndromes was significantly lesser than in those with acute coron ary syndromes (2.0 +/- 1.9 [SD] v 24.7 +/- 28.2 ng/mL; P < .0001), There we re significantly fewer histories of chest pain and prior myocardial infarct ion in patients with diseases other than acute coronary syndromes than in t hose with acute coronary syndromes (history of chest pain, 3 v 48 patients [P < .001]; history of prior myocardial infarction, 0 v 30 patients [P < .0 01]). In conclusion, elevated serum levels of cardiac troponin I, especiall y in the lower ranges, should be interpreted with caution, particularly in patients suffering from acute illnesses who lack other diagnostic features suggestive of acute coronary ischemic events. Copyright (C) 1999 by W.B. Sa unders Company.