Risk stratification of patients with minor troponin-I elevation unassociated with acute myocardial infarction

Background and Objectives: Although cardiac troponin I is widely used as a marker for myocardial infarction (MI), minor elevations of cardiac troponin I are also observed in other clinical situations. The prognostic factors for patients with these clinical features are not well established. The aim of this study was to discover the predictors of mortality for the patients who had minor troponin elevations without acute MI. Subjects and Methods: We enrolled consecutive 154 patients from the emergency department or inpatient units who had a peak troponin I level greater than the lower limit of detectability (0.04 ng/mL), and the level was also less than the suggestive value of MI (0.6 ng/mL). They were with chest pain or nonspecific symptoms of circulatory abnormality, but they lacked the traditional features of acute MI. The endpoint was defined as death from all causes. The Cox proportional hazard model was used to test the relationship between the clinical and biochemical variables and the outcomes. Results: During the follow-up period of 7.9±7.3 months, mortality occurred in 15 patients. Age, the creatine kinase myocardial isoform (CK-MB) level and the C-reactive protein (CRP) level as continuous variables had significant correlations with the occurrence of death. After adjusting for any possible confounders in the multivariate model, these variables remained as independent predictors of mortality: age (HR 1.07, CI 1.02-1.14, p=0.012), CK-MB level (HR 1.61, CI 1.16-2.24, p=0.005), and CRP level (HR 1.01, CI 1.00-1.01, p=0.025). Conclusion: Integration of the CK-MB and CRP levels, as well as age, can be used for risk-stratification in the patients showing minor troponin I elevation for reasons other than acute MI.