Rapid diagnosis of myocardial injury with troponin T and CK-MB relative index.

BACKGROUND

Current hospital practice involves protracted observation of chest-pain patients to rule out myocardial infarction. Concurrent measurement of multiple biomarkers may increase sensitivity and make rapid diagnosis feasible.

OBJECTIVE

We sought to determine the optimal biomarker strategy for highly sensitive, early diagnosis of myocardial injury.

STUDY DESIGN

A prospective evaluation of 171 acute coronary syndrome patients admitted to a single university medical center was performed. Blood tests for creatine kinase (CK), CK myocardial band isoenzyme (CK-MB), and troponin T were obtained at 0, 3, 6, 8, and 16 hours after presentation to the emergency department. Myocardial injury was defined as a troponin T level of >or=0.03 ng/mL.

RESULTS

Troponin T had sensitivities of 79.7%, 95.7%, and 98.4% at the time of initial presentation, 3 and 6 hours after presentation, respectively. Using a combination of troponin T and CK-MB relative index, sensitivity on presentation was increased to 90.6%. The sensitivity was improved to 97.9% and 100% at 3 and 6 hours, respectively.

CONCLUSION

This study demonstrates that the diagnosis of myocardial injury can be accurately excluded within 6 hours of admission with high sensitivity using troponin T. The combination of troponin T and CK-MB relative index provided the largest improvement in diagnostic sensitivity at patient arrival. These results support the feasibility of rapid, efficient triage for the emergent presentation of patients with chest pain.