Impact of extra-mitral valve cardiac involvement in patients with primary mitral regurgitation undergoing transcatheter edge-to-edge repair

Background: In the context of primary mitral regurgitation (PMR), the selection of patients for transcatheter edge-to-edge repair (TEER) does not include a systematic assessment of PMR-associated cardiac remodelling. Aims: We aimed to investigate the epidemiology and prognostic significance of different phenotypes of extra-mitral valve (MV) cardiac involvement in a large series of patients with PMR referred for TEER. Methods: The study included 654 patients from the multicentre Italian GIOTTO registry, stratified into groups according to extra-mitral valve (MV) cardiac involvement. The primary endpoint was all-cause death at 2-year follow-up. Results: Patients with no cardiac involvement (NI; n=58), left heart involvement (LHI; n=343) and right heart involvement (RHI; n=253) were analysed. Acute technical success was achieved in 98% of patients. Kaplan-Meier curve analysis revealed significantly worse survival in patients with LHI and RHI (p=0.041). On multivariate Cox regression analysis, extra-MV cardiac involvement, haemoglobin level and technical success were independent predictors of the primary endpoint occurrence. Conclusions: Grading cardiac involvement may help refine risk stratification, since at least 1 group of extra-MV cardiac involvement represents in itself a negative predictor of midterm outcome.