Prognostic Value of Circulating Micrornas Compared to High-Sensitivity Troponin T in Patients Presenting with Suspected Acute Coronary Syndrome to the Emergency Department.

Background: To evaluate the prognostic value of eleven microRNAs (miRNAs) compared to high-sensitivity Troponin T (hs-cTnT) in patients presenting with suspected acute coronary syndrome (ACS) to the emergency department (ED). Methods: 1,042 patients presenting between August 2014 and April 2017 were included. Expression levels of eleven microRNAs (miR-21-5p, miR-22-3p, miR-29a-3p, miR-92a-3p, miR-122-5p, miR-126-3p, miR-132-3p, miR-133a-3p, miR-134-5p, miR-191-3p, and miR-423-5p) were determined using RT-qPCR. All-cause mortality (ACM) and a composite of ACM, acute myocardial infarction (AMI) and stroke were defined as endpoints. Results: During a median follow-up of 399 (P25-P75: 381-525) days 58 patients (5.6%) died. The composite endpoint occurred in 86 patients (8.3%). Different expression levels of miR-21-5p (median, P25-P75: 5.28 [5.14-5.51] vs. 5.16 [4.97-5.35], p = 0.0033) and miR-122-5p (median, P25-P75: 5.17 [4.81-5.49] vs. 5.35 [5.01-5.69], p = 0.0184) were observed in patients who died compared to survivors. ROC-optimized cutoff of miR-21-5p (HR, P25-P75: 3.3 [1.2-9.4], p = 0.0239), but not miR-122-5p (HR, P25-P75: 0.4 [0.2-0.8], p = 0.0116), was predictive for all-cause mortality, even after adjustment in a multivariate model. Nevertheless, addition of miR-21-5p and miR-122-5p decreased prognostic accuracy of hs-cTnT for all-cause mortality (oAUC: 0.112, p = 0.0159). Hs-cTnT admission values had a high prognostic value for ACM (AUC [95%CI] = 0.794 [0.751-0.837]) and the composite of ACM, AMI and stroke (AUC [95%CI] = 0.745 [0.695-0.794]). Conclusions: Despite a different expression depending on outcomes miR-21-5p and miR-122-5p do not add prognostic information to hs-cTnT in patients presenting with suspected ACS to the ED.