Small changes in troponin T levels are common in patients with non-ST-segment elevation myocardial infarction and are linked to higher mortality.
OBJECTIVE
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.
Department of Medicine, Sahlgrenska University Hospital at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Christian
C
Bjurman
Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Mårten
M
Larsson
Department of Cardiology, Sahlgrenska University Hospital at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Per
P
Johanson
Department of Medicine, Sahlgrenska University Hospital at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Max
M
Petzold
Department of Medical Sciences, Cardiology and Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.
Bertil
B
Lindahl
Department of Medicine, Sahlgrenska University Hospital at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Michael L X
MLX
Fu
Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. Electronic address: ola.hammarsten@clinchem.gu.se.
Ola
O
Hammarsten
D000368:Aged; D000369:Aged, 80 and over; D003325:Coronary Care Units; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis / Q000401:mortality; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013548:Sweden / Q000453:epidemiology; D020107:Troponin T / Q000097:blood*
D020107:Troponin T
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