Undetectable high-sensitivity cardiac troponin T level in the emergency department and risk of myocardial infarction.
OBJECTIVE
This study sought to evaluate if an undetectable (<5 ng/l) high-sensitivity cardiac troponin T (hs-cTnT) level and an electrocardiogram (ECG) without signs of ischemia can rule out myocardial infarction (MI) in the emergency department (ED).


BACKGROUND
Chest pain is a common symptom often associated with benign conditions, but may be a sign of MI. Because there is no rapid way to rule out MI, many patients are admitted to the hospital.


METHODS
All patients who sought medical attention for chest pain and had at least 1 hs-cTnT analyzed during 2 years at the Karolinska University Hospital, Stockholm, Sweden, were included. We calculated the negative predictive values of an undetectable hs-cTnT and ECG without ischemia for MI and death within 30 days.


RESULTS
We included 14,636 patients, of whom 8,907 (61%) had an initial hs-cTnT of <5 ng/l; 21% had 5 to 14 ng/l, and 18% had >14 ng/l. During 30-day follow-up, 39 (0.44%) patients with undetectable hs-cTnT had a MI, of whom 15 (0.17%) had no ischemic ECG changes. The negative predictive value for MI within 30 days in patients with undetectable hs-cTnT and no ischemic ECG changes was 99.8% (95% confidence interval [CI]: 99.7 to 99.9). The negative predictive value for death was 100% (95% CI: 99.9 to 100).


CONCLUSIONS
All patients with chest pain who have an initial hs-cTnT level of <5 ng/l and no signs of ischemia on an ECG have a minimal risk of MI or death within 30 days, and can be safely discharged directly from the ED.
Department of Emergency Medicine, Karolinska University Hospital, Huddinge, Sweden; Department of Internal Medicine, Karolinska Institutet, Stockholm, Sweden.
Nadia
N
Bandstein
Unit of Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
Rickard
R
Ljung
Department of Emergency Medicine, Karolinska University Hospital, Huddinge, Sweden.
Magnus
M
Johansson
Department of Emergency Medicine, Karolinska University Hospital, Huddinge, Sweden; Department of Internal Medicine, Karolinska Institutet, Stockholm, Sweden. Electronic address: martin.holzmann@karolinska.se.
Martin J
MJ
Holzmann
D000368:Aged; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D003937:Diagnosis, Differential; D004562:Electrocardiography; D004636:Emergency Service, Hospital; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D013548:Sweden / Q000453:epidemiology; D020107:Troponin T / Q000097:blood*
D015415:Biomarkers; D020107:Troponin T
chest pain; emergency department; high-sensitivity troponin; myocardial infarction