Impact of mitral regurgitation aetiology on MitraClip outcomes: The MitraSwiss registry

Aims: The Swiss national registry on percutaneous mitral valve interventions (MitraSwiss) was established in 2011 to monitor safety/efficacy of percutaneous mitral valve repair (PMVR) with the MitraClip device. The aim of this analysis was to report the outcome after PMVR in a real-world, all-comers population and its predictors after inclusion of more than 1,200 patients, stratifying the results according to mitral regurgitation (MR) aetiology. Here we report the in-hospital, short and midterm outcomes of all patients prospectively enrolled. Methods and results: Since 2011, MitraSwiss has enrolled 1,212 patients with moderate and severe MR of functional (FMR) or degenerative (DMR) aetiology treated with PMVR in 10 centres. Pre-specified endpoints included clinical, echocardiographic and functional parameters with follow-up planned up to five years. Outcomes are compared according to MR aetiology. Acute procedural success was achieved in 91.5% of cases, with no differences between FMR and DMR and sustained good midterm results. NYHA class and pulmonary pressure improved significantly in both cohorts. Cumulative probability of death at five years was 54% (95% CI: 45-63) in FMR and 45% (95% CI: 37-54) in DMR (HR 1.15, p=0.009). Age, anaemia, impaired renal function and reduced left ventricular ejection fraction resulted in being independent predictors of death at five years. Conclusions: In a large contemporary cohort of non-surgical patients with severe MR, the safety and effectiveness of PMVR have been confirmed. At midterm follow-up, mortality and MACE were lower in DMR patients, though MR aetiology was not directly and independently associated with outcome.