Optimal results immediately after MitraClip therapy or surgical edge-to-edge repair for functional mitral regurgitation: are they really stable at 4 years?

OBJECTIVES: Recurrent mitral regurgitation (MR) is common after surgical and percutaneous (MitraClip) treatment of functional MR (FMR). However, the Everest II trial suggested that, in patients with secondary MR and initially successful MitraClip therapy, the results were sustained at 4 years and were comparable with surgery in terms of late efficacy. The aim of this study was to assess whether both those findings were confirmed by our own experience. METHODS: We reviewed 143 patients who had an initial optimal result (residual MR <= 1+ at discharge) after MitraClip therapy (85 patients) or surgical edge-to-edge (EE) repair (58 patients) for severe secondary MR (mean ejection fraction 28 +/- 8.5%). Patients with MR >= 2+ at hospital discharge were excluded. The two groups were comparable. Only age and logistic EuroSCORE were higher in the MitraClip group. RESULTS: Follow-up was 100% complete (median 3.2 years; interquartile range 1.8; 6.1). Freedom from cardiac death at 4 years (81 +/- 5.2 vs 84 +/- 4.6%, P = 0.5) was similar in the surgical and MitraClip group. The initial optimal MitraClip results did not remain stable. At 1 year, 32.5% of the patients had developed MR >= 2+ (P = 0.0001 compared with discharge). Afterwards, patients with an echocardiographic follow-up at 2 years (60 patients), 3 years (40 patients) and 4 years (21 patients) showed a significant increase in the severity of MR compared with the corresponding 1 year grade (all P < 0.01). Freedom from MR >= 3+ at 4 years was 75 +/- 7.6% in the MitraClip group and 94 +/- 3.3% in the surgical one (P = 0.04). Freedom from MR >= 2+ at 4 years was 37 +/- 7.2 vs 82 +/- 5.2%, respectively (P = 0.0001). Cox regression analysis identified the use of MitraClip as a predictor of recurrence of MR >= 2+ [ hazard ratio (HR) 5.2, 95% confidence interval (CI) 2.5-10.8, P = 0.0001] as well as of MR >= 3 (HR 3.5, 95% CI 0.9-13.1, P = 0.05). CONCLUSIONS: In patients with FMR and optimal mitral competence after MitraClip implantation, the recurrence of significant MR at 4 years is not uncommon. This study does not confirm previous observations reported in the Everest II randomized controlled trial indicating that, if the MitraClip therapy was initially successful, the results were sustained at 4 years. When compared with the surgical EE combined with annuloplasty, MitraClip therapy provides lower efficacy at 4 years.