Factors associated with favorable outcomes in patients undergoing transcatheter edge-to-edge mitral valve repair (TEER) with the mitraclip device

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Transcatheter edge-to-edge mitral valve repair (TEER) has over the years become a viable alternative to surgery in high-risk patients with severe symptomatic mitral regurgitation (MR). Selection of optimal candidates who will benefit from the procedure remains challenging. Our study aims to determine clinical, echocardiographic and procedural factors associated with favorable outcomes after mitraclip implantation. Methods We retrospectively analyzed the data concerning patients who underwent MitraClip implantation for symptomatic severe MR in our institution. All patients underwent a clinical evaluation and a transthoracic echocardiography before the procedure, and at follow up (between one and up to three months after the index procedure). A clinical endpoint combining absence of cardiovascular death, absence of rehospitalization for heart failure and improvement of at least 1 class New York Heart Association NYHA at three months, was used to define a good response. Results Among 109 patients referred to our institution for TEER since January 2018, 106 had a successful clip implantation and were included in our study. 76 of them had a primary MR and 30 others a secondary mitral regurgitation (SMR). The primary endpoint was achieved in 65% of those patients. Reduction of MR severity to less than grade 2+ was achieved in 87% of the patients. A high body mass index (p = 0.03), a high level of NT-proBNP at admission (p = 0.02), the association with at least a moderate tricuspid regurgitation prior to mitraclip implantation (p = 0.02) and a severe residual mitral regurgitation (p = 0.01) were predictive of a worse outcome in all patients. In the group of secondary MR, patients who reached the primary endpoint had significantly a lower telediastolic diameter (p = 0.02). A post procedural transvalvular mitral gradient superior to 4.4 mmHg was associated with a worse prognosis in patients with primary mitral regurgitation (p = 0.004) but not in the group of secondary mitral regurgitation (p = 0.7). Furthermore, the ratios EROA/LVEDV and VR/LVEDV defining proportionate mitral regurgitation were not correlated to any benefit in the secondary MR group. Conclusion Our study in real life patients found some elements supporting the results of former studies about predictors of outcomes after mitraclip treatment. Tricuspid regurgitation prior to the procedure and an elevated mitral valve pressure gradient after clip implantation are correlated with a worse prognosis. In accordance with recent literature, an elevate mean gradient seems to have less impact on prognosis in SMR, fostering to get optimal MR reduction in those patients. Identifying criteria that would predict insufficient benefit of Mitraclip implantation is necessary to avoid futility.