CARDIAC TROPONIN-I AS A PREDICTOR OF MAJOR CARDIAC EVENTS IN EMERGENCY DEPARTMENT PATIENTS WITH ACUTE CHEST PAIN

Objectives. We sought to evaluate the diagnostic and prognostic value of cardiac troponin I (cTnI) in emergency department (ED) patients wit h chest pain. Background. Although cTnI has been shown to correlate wi th an increased risk for complications in patients with unstable angin a, the prognostic significance of this assay in the heterogeneous popu lation of patients who present to the ED with chest pain is unclear. M ethods. cTnI and creatine kinase MB fraction (CK-MB) mass concentratio n were collected serially during the first 48 h from onset of symptoms in 1,047 patients greater than or equal to 30 years old admitted for acute chest pain. Sensitivity, specificity and receiver operating char acteristic curves were calculated for cTnI and CK-MB collected in the first 24 h. Results. The sensitivity, specificity and positive predict ive value of cTnI for major cardiac events were 47%, 80% and 19%, resp ectively. Among patients were who ruled out for myocardial infarction, cTnI was elevated in 26% who had major cardiac complications compared with 5% for CK MB; the positive predictive value for an abnormal cTnI result was 8%. Elevated cTnI in the presence of ischemia on the elect rocardiogram was associated with an adjusted odds ratio of 1.8 (95% co nfidence interval 1.1 to 2.9) for major cardiac events within 72 h. Am ong patients without a myocardial infarction or unstable angina, cTnI was not an independent correlate of complications. Conclusions. In pat ients presenting to the ED with acute chest pain, cTnI was an independ ent predictor of major cardiac events. However, the positive predictiv e value of an abnormal assay result was not high in this heterogeneous cohort.