Use of the Centaur TnI-Ultra Assay for Detection of Myocardial Infarction and Adverse Events in Patients Presenting With Symptoms Suggestive of Acute Coronary Syndrome

Abstract

Background: We determined the diagnostic accuracy of the Advia Centaur TnI-Ultra assay for detecting myocardial infarction (MI) and assessing risk of adverse events in patients presenting with ischemic symptoms suggestive of acute coronary syndrome. Methods: We measured cardiac troponin I (cTnI) on admission and 6–24 h after admission (follow-up) in plasma specimens from 371 consecutive patients. The end point was the first of cardiac event or death within 60 days. We estimated survival curves using the Kaplan-Meier method and compared groups with the log rank statistic. Results: MI was established in 49 patients (13%). Clinical sensitivities and specificities for MI based on the 99th percentile (0.04 μg/L) were 74% and 84%, respectively, on admission and 94% and 81% at follow-up. ROC curves showed significantly higher accuracy for MI in the follow-up specimen compared with admission (P = 0.001). Overall there were 2 cardiac deaths, 1 noncardiac death, 49 MIs, 7 coronary artery bypass grafts, and 36 percutaneous coronary interventions in 59 patients during follow-up. The event rate in those with cTnI 0.04–0.10 μg/L, or >0.10 μg/L (2.8% vs 11.1%, 24.1%, 55.1%, respectively; P <0.0001). Relative risks for the increasing cTnI cutoff groups were 3.9 (95% CI 1.2–13), 8.9 (2.4–34), and 25 (7.3–82) after adjustment for age, diabetes, history of hypertension, previous MI, and estimated glomerular filtration rate. Conclusions: The TnI-Ultra assay is a sensitive, early diagnostic biomarker for MI and an independent predictor of adverse events at any measurable cTnI in patients with symptoms of acute coronary syndrome.