The prognostic significance of troponin I and troponin T.
OBJECTIVE
To determine and compare the prognostic abilities of early, single-sample measurements of cardiac troponin I (cTn-I), cardiac troponin T (cTn-T), and creatine kinase-MB (CK-MB) among ED patients with possible myocardial ischemia.


METHODS
Prospective collection of clinical and serologic data using an identity-unlinked technique from patients with possible myocardial ischemia at 2 urban EDs. Outcome data concerning the occurrence of adverse events (AEs) during the 14 days after enrollment were used to calculate and compare the relative risks (RRs) and predictive values (with 95% confidence intervals) of the 3 markers for predicting AEs.


RESULTS
Among the 401 study patients, 105 AEs occurred in 67 patients. cTn-I, cTn-T, and CK-MB were all significantly predictive of AEs, with RRs of 3.87 (2.39, 6.26), 3.03 (1.92, 4.79), and 6.45 (4.74, 8.77), respectively. For prediction of AEs, sensitivity for each of the 3 markers was low (cTn-I = 15.38, cTn-T = 24.62, CK-MB = 15.38), while specificity was high (cTn-I = 97.62, cTn-T = 93.15, CK-MB = 99.70). No significant difference in predictive ability was found between cTn-I and cTn-T. However, a positive CK-MB result was a stronger predictor of AEs than either cTn-I (p = 0.01) or cTn-T (p = 0.001).


CONCLUSIONS
No significant difference in predictive abilities was found between cTn-I and cTn-T. However, routine testing for both CK-MB and either of the troponins may optimize early identification of high-risk patients so they may be targeted for a higher level of care and consideration of more aggressive therapies.
Department of Emergency Medicine, Johns Hopkins Hospital, Baltimore, Maryland, USA. ggreen@gwgate1.jhmi.jhu.edu
G B
GB
Green
D J
DJ
Li
E S
ES
Bessman
J L
JL
Cox
G D
GD
Kelen
D W
DW
Chan
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D004632:Emergency Medical Services; D005260:Female; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014336:Troponin / Q000097:blood*; D019210:Troponin I / Q000097:blood*; D020107:Troponin T
D015415:Biomarkers; D007527:Isoenzymes; D014336:Troponin; D019210:Troponin I; D020107:Troponin T; D003402:Creatine Kinase