Secondary mitral regurgitation—Insights from microRNA assessment

Background While secondary mitral regurgitation (sMR) is associated with adverse outcome in heart failure with reduced ejection fraction (HFrEF), key pathophysiologic mechanisms remain poorly understood and might be elucidated by microRNAs (miRNA/miR), that were recently related to cardiac remodelling. This study sought to assess (i) the differences of miRNA profiles in patients with severe sMR compared to matched disease controls, (ii) the correlation between circulating miRNAs and surrogates of sMR severity as well as (iii) the prognostic implications of miRNA levels in severe sMR. Materials and methods Sixty‐six HFrEF patients were included, of these 44 patients with severe sMR 2:1 matched to HFrEF controls with no/mild sMR. A comprehensive set of miRNAs (miR‐21, miR‐29a, miR‐122, miR‐132, miR‐133a, miR‐let7i) were measured and correlated to echocardiographic sMR severity. Results miRNA patterns differed distinctly between patients with severe sMR and HFrEF controls (P