A rapid troponin I assay is not optimal for determination of troponin status and prediction of subsequent cardiac events at suspicion of unstable coronary syndromes.
BACKGROUND: Troponin is a specific marker of myocardial damage. For early prediction of coronary events in patients with suspicion of acute coronary syndromes the assay also needs to be highly sensitive. METHODS AND RESULTS: A rapid troponin I assay was performed prior to inclusion in 4447 acute coronary syndrome patients in the GUSTO-IV trial. A quantitative troponin T analysis was later performed on blood samples obtained at randomization by a central laboratory. There was an agreement between the rapid troponin I assay and troponin T (< or =/>0.1 microg/l) in 3596 (80.9%) patients. A positive rapid troponin I was identifying any elevation of troponin T (>0.01 microg/l) in 1990 patients (90.4%) whereas a negative rapid troponin I was corresponding to negative troponin T (< or =0.01 microg/l) in only 1217 patients (54.2%). Patients with a positive versus negative rapid troponin I had an increased risk of death or myocardial infarction at 30 days (9.3 vs. 5.9%; odds ratio, O.R. 1.64; 95% confidence interval, 1.31-2.06). Troponin T elevation (>0.1 microg/l) provided a better (10.5 v. 4.9%, O.R. 2.26; C.I. 1.79-2.85) risk stratification. Regardless of a positive or a negative rapid troponin I, the troponin T result (>0.1 vs. < or =0.1 microg/l) stratified the patients into high and low risk of events at 30 days, (10.3 vs. 5.7%, P=0.002) and (11.5 vs. 4.8%, P<0.001), respectively. CONCLUSION: In a population with non-ST elevation acute coronary syndrome a positive rapid troponin I assay is a specific indicator of troponin elevation and a predictor of early outcome. However, a negative rapid troponin I is not a reliable indicator of the absence of myocardial damage and does not indicate a low risk of subsequent cardiac events. A rapid troponin I assay was performed prior to inclusion in 4447 acute coronary syndrome patients in the GUSTO-IV trial and related to a centrally analyzed quantitative troponin T test. A positive rapid troponin I was well corresponding to any elevation of troponin T (>0.01 microg/l) and predicted an unfavorable outcome at 30 days. However, a negative rapid troponin I was corresponding to troponin T < or =0.01 microg/l in only half of the patients. Troponin T >0.1 microg/l vs. < or =0.1 microg/l provided a better risk stratification than the rapid troponin I result. For patients with troponin T elevation (>0.1 microg/l) the 30 day event rate was high regardless of the rapid troponin I result.
|Keywords||0 (Antibodies, Monoclonal), 0 (Anticoagulants), 0 (Immunoglobulins, Fab), 0 (Platelet Glycoprotein GPIIb-IIIa Complex), 0 (Troponin I), 0 (Troponin T), 143653-53-6 (abciximab), Acute Disease, Aged, Antibodies, Monoclonal/therapeutic use, Anticoagulants/therapeutic use, Comparative Study, Coronary Disease/blood/*diagnosis, Double-Blind Method, Female, Follow-Up Studies, Human, Immunoglobulins, Fab/therapeutic use, Male, Middle Aged, Platelet Glycoprotein GPIIb-IIIa Complex/antagonists & inhibitors, Predictive Value of Tests, Risk Assessment, Sensitivity and Specificity, Support, Non-U.S. Gov't, Troponin I/*blood, Troponin T/blood|
|Persistent URL||dx.doi.org/10.1016/S0167-5273(03)00157-8, hdl.handle.net/1765/5719|
James, S.K., Lindahl, B., Califf, R.M., Simoons, M.L., Venge, P., Wallentin, L.C., & Armstrong, P.W.. (2004). A rapid troponin I assay is not optimal for determination of troponin status and prediction of subsequent cardiac events at suspicion of unstable coronary syndromes.. International Journal of Cardiology, 93(2-3), 113–120. doi:10.1016/S0167-5273(03)00157-8