Abstract 9911: Circulating miR-499-5p and -21 are Sensitive and Specific Biomarkers of NSTEMI in Geriatric Patients with Borderline cTnT Elevation

Abstract

Background: Geriatric patients with NSTEMI often present atypical symptoms, uninterpretable electrocardiogram and borderline cTnT elevation; therefore, these patients can be misdiagnosed and inappropriately treated. Some circulating miRNAs have emerged as novel biomarkers of MI. Our objective was to establish whether selected circulating microRNAs (miRNAs) are biomarkers of non-ST elevation myocardial infarction (NSTEMI) in geriatric patients and, eventually, whether miRNAs exhibit higher sensitivity and specificity than cardiac troponin T (cTnT) in patients with borderline cTnT elevation. Methods and Results: Elderly individuals (81.4 ± 7.1 years old) were enrolled; 61 patients presented with acute NSTEMI complicated by congestive heart failure (CHF) in 85 % of cases; 47 patients presented with acute CHF without MI. Blood samples were collected 4-9 hours after the onset of symptoms. A third group comprised 46 age-matched healthy control subjects (CTR). Plasma levels of miR-1, -21, -133a, -146a, -208, -423-5p and -499-5p were analysed. NSTEMI was associated with a ∼80-fold and ∼6-fold increase in miR-499-5p and -21, respectively, whereas CHF caused a ∼20-fold increase in miR-423-5p vs CTR. Moreover, miR-499-5p and -21 exhibited the highest sensitivity and specificity in differentiating between NSTEMI and CHF. Interestingly, among subjects with borderline cTnT elevation (0.03-0.10 ng/ml), NSTEMI (n=27) and CHF (n=21) patients were differentiated by miR-499-5p (AUC=0.90), miR-21 (AUC=0.89) and their combination (AUC=0.92), more effectively than by cTnT (AUC =0.61). Conclusions: Circulating miR-499-5p and -21 are sensitive and specific biomarkers of NSTEMI in the geriatric population; in patients with borderline increase in cTnT, these miRNAs are more accurate that cTnT in discriminating NSTEMI vs. CHF patients.