Abstract 15144: Classic Acute Myocardial Infarction Rule-Out Using Non-Ischemic 12-Lead Electrocardiography and Serial High-Sensitivity Cardiac Troponin Below the 99th Percentile: Safe and Efficient, and Simpler Than Other Approaches

Introduction:Using high-sensitivity cardiac troponin (hs-cTn) I and T assays, various strategies have been developed to expedite the evaluation of patients with suspected acute myocardial infarction (AMI). Whether such approaches are superior to the standard of care involving the use of 12-lead electrocardiography (ECG) and serial cTn below the 99thpercentile upper-reference limit (URL) is uncertain.Objective:Compare the diagnostic and prognostic performance of strategies involving 0- and 3-hour (h) hs-cTnI testing to rule-out AMI.Methods:Post-hoc analysis of the Use of Troponin in ACS (UTROPIA) study (NCT02060760); a prospective US-based study of consecutive, unselected ED patients in whom serial (0/3h) cTnI was obtained on clinical indication and hs-cTnI (Abbott, investigational) measured; 99thURLs: F 16 ng/L, M 34 ng/L. We compared the diagnostic (index AMI) and prognostic (AMI or death at 30-days) performance of three distinct rule-out pathways involving 0- and/or 3-h hs-cTnI testing: a) European Society of Cardiology (ESC), b) High-STEACS, and c) serial testing <99thpercentile (classic) in a UTROPIA patient subset with established symptom onset.Results:Among 582 patients, 70 (12%) had AMI. Prognostic sensitivities (95% CI) and percent eligible for rule-out using hs-cTnI alone without ECG: a) classic: 93% (87.0-98.9) and 77%, b) ESC: 70.4% (59.8-81.0) and 86%, and c) High-STEACS: 93% (87.0-98.9) and 68%. Prognostic sensitivities and percent eligible for rule-out using hs-cTnI alone with ECG: a) classic: 100% (94.9-100) and 33%, b) ESC: 94.4% (89.0-99.7) and 35%, and c) High-STEACS: 100% (94.9-100) and 30%.Conclusions:Our study demonstrates that 0/3h pathways, in particular the ESC model, result in unacceptably low diagnostic and prognostic sensitivities when used in isolation without ECG findings. For ruling-out, both the classic and High-STEACS, but not the ESC, pathways have excellent diagnostic and prognostic performance. Our findings showing similar rule-out performance for the classic approach indicate that the standard-of-care approach involving a non-ischemic ECG and serial hs-cTnI <99thsex-specific URL is safe, efficient, and potentially more attractive to clinicians because of its simplicity.