Clinical implications of the change of cardiac troponin I levels in patients with acute chest pain - An evaluation with respect to the Universal Definition of Myocardial Infarction

Background: The Universal Definition of Myocardial Infarction incorporates elevated cardiac troponin levels (>. 99th percentile) together with a significant rise/fall of troponins as biochemical criterion. We sought to evaluate the clinical implications of the relative change of cardiac troponin I (cTnI) levels with respect to the Universal Definition in patients with acute chest pain. Methods: cTnI (Stratus CS) was measured serially in 454 patients within 24 h from admission. Acute myocardial infarction (AMI) was defined using the criteria adapted to the ESC/ACC consensus document, or corresponding to the Universal Definition together with prespecified cTnI changes of ≥. 20%, ≥. 50% and ≥. 100%. Follow-up was completed after 5.8. years. Results: A peak cTnI level above the 99th percentile together with a cTnI change of ≥. 20% was found in 160 patients of whom 25 did not have AMI according to the ESC/ACC criteria. These 160 patients had a significantly raised mortality (HR 2.5 [95% CI 1.7-3.8]). Higher cTnI deltas were not associated with higher mortalities but identified smaller patient cohorts at risk. Conclusions: The Universal Definition of AMI together with a ≥. 20% cTnI change appears to improve the discrimination of acute from chronic causes of cTnI release, and allows a reliable identification of patients at risk.