Extent and progression of cardiac damage in patients with primary mitral regurgitation undergoing surgical repair

Objectives: The progression of extra-mitral valve (MV) cardiac damage in patients with primary mitral regurgitation (MR) following surgical repair has not been described. We aimed to investigate the evolution of extra-MV cardiac damage after MV repair and to assess its prognostic significance. Methods: Patients with severe primary MR undergoing surgical repair at 5 referral centers were included when echocardiographic follow-up assessment was available. Based on echocardiographic parameters at baseline and at a median follow-up of 7(IQR 4-11) months after MV repair, patients were hierarchically classified as follows: stage 0: no cardiac damage; stage 1: left ventricular dilatation and/or dysfunction; stage 2: left atrial dilatation and/or atrial fibrillation; stage 3: pulmonary hypertension and/or significant tricuspid regurgitation. The primary outcome was all-cause mortality. Results: A total of 764 patients (mean age 62 ± 13 years, 70% men) were included. Compared to baseline, 43% improved at least 1 stage, 49% remained unchanged, and 8% worsened at least 1 stage during follow-up after MV repair. At a median follow-up of 91 months after MV repair, 94 patients (12%) died. By multivariate Cox regression analysis, after adjusting for potential confounders, extra-MV cardiac damage staging at follow-up (HR per-1-stage-increase = 1.571; p = 0.009) and cardiac damage evolution (improved group, HR = 0.467; p = 0.034; worsened group, HR = 2.481, p = 0.037) were independently associated with all-cause mortality and had incremental prognostic value over preprocedural assessment. Conclusions: Extra-MV cardiac damage improves significantly after MV repair, and its evolution is independently associated with all-cause mortality, suggesting the importance of comparative echocardiographic assessment following MV repair to improve risk stratification.