A-024 Prognosis for Adverse Events in Suspected ACS Without MI, and Subgroups with or Without History of Incident and Previous MACE Using the Atellica IM High-Sensitivity Troponin I Assay

Abstract Background Cardiac troponin (cTn) is the preferred biomarker to aid in the diagnosis of myocardial infarction (MI). This study evaluated if cTnI predicts all-cause mortality (ACM) or major adverse cardiac events (MACE) (MI, cardiac death, heart failure hospitalization, or urgent revascularization) in the following year among ED patients presenting with chest pain suspected of acute coronary syndrome, but not diagnosed with MI. Methods Adult patients suspected of acute coronary syndrome (n=2374) at 29 U.S. sites between 2014–2016 were prospectively followed for up to one year to evaluate the association between cTnI, all-cause mortality (ACM) (inclusive of initial presentation visit events), and MACE (defined as post-discharge MI, cardiac death, heart failure hospitalization, and urgent [emergency] coronary revascularization). Patients with AMI at presentation (n=310; 13%) were excluded. Survival and proportional hazard regression analyses were performed on the primary analysis population (n=2064) made up of two subcohorts—one with (n=874) and the other without (n=1190) history of incident/prior MACE. cTnI concentrations were measured in lithium heparin plasma samples using the Atellica IM High-Sensitivity (hs) Troponin I (TnIH) assay. Pre- and post-test risk and unadjusted and adjusted hazard ratios (aHR) with 95% confidence intervals (CI) were calculated for baseline cTnI concentrations above, and at or below, the overall 99th percentile upper reference limit (URL). The adjusted models included the covariates of eGFR, hypertension, prior history of revascularization, prior heart failure, and sex. Results The median age of the primary analysis population was 56 (IQR, 47–64) years; 54.8% were males. Patients in the primary analysis population and both subcohorts with presentation baseline cTnI above the 99th percentile URL had greater rates of ACM/MACE at one year—primary analysis population: >99th percentile, 39.5% [75 events/190 patients] vs. <=99th percentile, 12.9% [242/1874], aHR was 1.85 [95%CI 1.39–2.47] at 365 days; subcohort without history of incident/prior MACE: 15.1% [8/53] vs. 4.4% [50/1137], aHR was 2.79 [1.28–6.08]; subcohort with history of incident/prior MACE, 48.9% [67/137] vs. 26.1% [192/737], aHR was 1.56 [1.15–2.12]. Conclusion The results of this study show that patients without MI but with cTnI above versus at or below the overall 99th percentile URL cutoff were at increased risk of ACM and MACE at one year.