Aims: Secondary mitral regurgitation (MR) negatively affects prognosis in acutely decompensated heart failure (ADHF), but can be rapidly sensitive to changes in volume status and medical interventions. We sought to assess the evolution of secondary MR in patients hospitalized for ADHF and its prognostic implications. Methods: We retrospectively enrolled 782 patients admitted for ADHF with at least two in-hospital echocardiographic evaluations of MR. We classified MR severity as none-mild or moderate-severe. Based on MR evolution, patients were divided into 'persistent moderate-severe MR', 'improved MR' (from moderate-severe to none-mild) and 'persistent none-mild MR'. Results: Four hundred and forty patients (56%) had moderate-severe MR at first evaluation, of whom 144 (33% of patients with baseline moderate-severe MR) had 'improved MR', while 296 (67%) had 'persistent moderate-severe MR'. Patients with improved MR had better clinical, laboratory and echocardiographic parameters of decongestion at discharge compared with those with persistent moderate-severe MR and showed a higher up-titration of recommended therapies. Left ventricular volume, ejection fraction and serum urea were the predictors of improved MR at multivariable analysis. After adjustment, no differences in 5-years survival (primary outcome) were observed according to baseline MR severity. When patients were stratified according to the in-hospital changes in MR severity, improved MR was associated with lower risk of 5-years mortality, compared with both persistent none-mild MR [hazard ratio (HR) = 0.505, P = 0.032] and persistent moderate-severe MR (HR = 0.556, P = 0.040). Conclusions: The severity of MR frequently improved during hospitalization for ADHF; the extent and the changes in MR severity during the in-hospital stay identified distinct patient phenotypes, and seemed to portend different long-term outcomes, with higher 5-years survival associated with improvement in MR.
