Comparison of High-Sensitive Cardiac Troponin-T Changes between Non-ST-Segment Elevation Myocardial Infarction and Non-Coronary Artery Patients

Background In the absence of acute coronary syndrome (ACS), various conditions may increase the level of cardiac troponins. Objectives We aimed to determine the absolute and relative changes of high-sensitive cardiac troponin T (hs-cTnT) in 2 groups of patients: non-ST-segment-elevation myocardial infarction (NSTEMI) and non-ACS patients. Methods In this longitudinal study, performed between December 2011 and July 2012, we calculated the absolute and relative changes of hs-cTnT and troponin velocity in consecutive patients, admitted to the emergency department of Tehran Heart Center. The patients had symptoms of acute MI with elevated baseline hs-cTnT levels. Blood sampling was performed 3 times following admission. The hs-cTnT changes were evaluated and compared between the 2 groups of NSTEMI and non-ACS patients. Results After exclusion, the second and third samples (taken 12 and 36 hours after admission on average, respectively) were available in 889 and 641 patients, respectively. Cardiovascular risk factors, including hyperlipidemia, diabetes mellitus, smoking, and history of coronary events or intervention, were significantly more frequent in the NSTEMI group, compared to the non-ACS group. The hs-cTnT level at baseline and in the subsequent samples was significantly higher in the NSTEMI group, compared to the non-ACS group. Also, the absolute and relative changes in hs-cTnT were more significant in the NSTEMI group. Moreover, hs-cTnT velocity within the first 12 hours was significantly higher in the NSTEMI group, compared to the non-ACS group (18.85 ± 84.89 ng/L/h vs. 4.96 ± 14.58 ng/L/h; P < 0.001). Conclusions The changes in hs-cTnT (ie, absolute, relative, and velocity changes) were more significant in the NSTEMI group in comparison with non-ACS patients.