Left Atrial Size Is a Potent Predictor of Mortality in Mitral Regurgitation Due to Flail Leaflets

Abstract
Background—Left atrium (LA) enlargement is common in organic mitral regurgitation (MR) and is an emerging prognostic indicator. However, outcome implications of LA enlargement have not been analyzed in the context of routine clinical practice and in a multicenter study. Methods and Results—The Mitral Regurgitation International DAtabase (MIDA) registry enrolls patients with organic MR due to flail leaflets, diagnosed in routine clinical practice, in 5 US and European centers. We investigated the relation between LA diameter and mortality under medical treatment and after mitral surgery in 788 patients in sinus rhythm (64±12 years; median LA, 48 [43 to 52] mm). LA diameter was independently associated with survival after diagnosis (hazard ratio, 1.08 [1.04 to 1.12] per 1 mm increment). Compared with patients with LA <55 mm, those with LA ≥55 mm had lower 8-year overall survival (P<0.001). LA ≥55 mm independently predicted overall mortality (hazard ratio, 3.67 [1.95 to 6.88]) and cardiac mortality (hazard r...