Measurement of cardiac troponin T is an effective method for predicting complications among emergency department patients with chest pain.
OBJECTIVE
To determine the test performance characteristics of serum cardiac troponin T (cTnT) measurement for diagnosis of acute myocardial infarction (AMI), and to determine the ability of cTnT to stratify emergency department patients with chest pain into high- and low-risk groups for cardiac complications.


METHODS
We conducted a prospective observational cohort study with convenience sampling in a tertiary care, urban ED. The study sample comprised 667 patients presenting to the ED with a complaint of chest pain or other symptoms suggesting acute ischemic coronary syndrome (AICS). Patients were assigned to different blood sampling protocols for cTnT therapy on the basis of their ECG at presentation: nondiagnostic for AMI at 0, 3, 6, 9, 12, and 24 hours after ED presentation; or ECG diagnostic for AMI at 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 18, and 24 hours after ED presentation.


RESULTS
Of 667 patients, 34 had AMI diagnosed within 24 hours of ED arrival. Using a .2 microgram/L discrimination level for cTnT, sensitivity for AMI within 24 hours of ED arrival was 97% (95% confidence interval, 91.4% to 99.9%), and specificity was 92% (89.8%-94.1%). When the effects of age, race, sex, and creatine kinase-MB isoenzyme subunit test results were controlled, a patient with cTnT of .2 microgram/L or greater was 3.5 (1.4 to 9.1) times more likely to have a cardiac complication within 60 days of ED arrival than a patient with a cTnT value below .2 microgram/L.


CONCLUSIONS
Measurement of cTnT will accurately identify myocardial necrosis in patients presenting to the ED with possible AICS. Elevated cTnT values identify patients at increased risk of cardiac complications.
Sayre
M R
MR
Department of Emergency Medicine, University of Cincinnati College of Medicine, OH, USA. michael.sayre@uc.edu
Kaufmann
K H
KH
Chen
I W
IW
Sperling
M
M
Sidman
R D
RD
Diercks
D B
DB
Liu
T
T
Gibler
W B
WB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000209:etiology*; D003402:Creatine Kinase / Q000097:blood; D004562:Electrocardiography; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000175:diagnosis* / Q000378:metabolism; D011446:Prospective Studies; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors; D014218:Triage; D014336:Troponin / Q000097:blood*; D020107:Troponin T
D015415:Biomarkers; D007527:Isoenzymes; D014336:Troponin; D020107:Troponin T; D003402:Creatine Kinase