Objectives: The purpose of this study was to examine the extent of change in troponin T levels in patients with non-ST-segment elevation myocardial infarction (NSTEMI).
Background: Changes in cardiac troponin T (cTnT) levels are required for the diagnosis of NSTEMI, according to the new universal definition of acute myocardial infarction. A relative change of 20% to 230% and an absolute change of 7 to 9 ng/l have been suggested as cutoff points.
Methods: In a clinical setting, where a change in cTnT was not mandatory for the diagnosis of NSTEMI, serial samples of cTnT were measured with a high-sensitivity cTnT (hs-cTnT) assay, and 37 clinical parameters were evaluated in 1,178 patients with a final diagnosis of NSTEMI presenting <24 h after symptom onset.
Results: After 6 h of observation, the relative change in the hs-cTnT level remained <20% in 26% and the absolute change <9 ng/l in 12% of the NSTEMI patients. A relative hs-cTnT change <20% was linked to higher long-term mortality across quartiles (p = 0.002) and in multivariate analyses (hazard ratio: 1.61 [95% confidence interval: 1.17 to 2.21], p = 0.004), whereas 30-day mortality was similar across quartiles of relative hs-cTnT change.
Conclusions: Because stable hs-TnT levels are common in patients with a clinical diagnosis of NSTEMI in our hospital, a small hs-cTnT change may not be useful to exclude NSTEMI, particularly as these patients show both short-term and long-term mortality at least as high as patients with large changes in hs-cTnT.
Keywords: CCU; CPU; ECG; HR; IQR; MI; NCCP; NSTEMI; cTnT; cardiac troponin T; chest pain unit; coronary care unit; electrocardiogram; hazard ratio; high-sensitivity cardiac troponin T; hs-cTnT; interquartile range; mortality; myocardial infarction; noncardiac chest pain; non–ST-segment elevation myocardial infarction; troponin T change.
Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.