Transcatheter mitral replacement: what are the outcomes of un-eligible patients compared to treated?

Abstract Background/Introduction Transcatheter mitral valve replacement (TMVR) is emerging in recent years as a promising tool to treat mitral regurgitation, however its applicability in the real world remains limited. Purpose The aim of the study is to assess the real-world screening success rate of TMVR in native anatomy and the 1-year outcomes of both accepted and refused patients as well as clinical results. Methods Retrospective analysis was performed on all patients screened for TMVR at our Valve Center, eligible for 1-year follow-up. In-hospital data of all patients admitted to our Department are prospectively collected. Follow-up was done through outpatient visits and/or telephone calls. Results Out of 3400 patients referred to mitral treatment at our department between January 2016-January 2022, 92 were submitted to screening for TMVR. Among these, 48 patients (49%) were accepted and treated with TMVR while 44 (44.8%) were refused (RG). The main reasons for rejection were anatomy unfeasibility in 25 patients (59%) and frailty in 5(11%). Main reasons for anatomy unfeasibility were risk LVOT obstruction (n=15; 60%), annular dimension (n=8; 33%) and ventricular dimension (n=2; 8,3%).Major baseline characteristics between groups were similar including age (85 vs 84), STS (12 vs 13), ejection fraction and LVEDD. However, refused patients had higher filtration rate than TMVR (80 vs 45 ml/min respectively (p=0.001)).All patients accepted were treated with TMVR: 7 patients received Tiara and 24 Tendyne. Procedure success in the TMVR group was 96% (46/48). Patients refused from TMVR were treated with Mitraclip in 5(11%) cases, 37(84%) were left in medical therapy and 2 (4,5%) underwent surgery. 1-year overall survival 65.2±51.3 vs 54.8±36.5 in TMVR and refused group respectively (p=0.002)(Figure 1). 6 deaths (2 cardiac, 33%) occurred in the TMVR compared to 37 (32 cardiac, 86%) in the refused group. Freedom from Cardiac death was 98±19% TMVR vs 75±65% (p<0.001)(Figure 2). NYHA class improved in 98% of cases in TMVR group but worsened in 80% in refused group, (p<0.001). TMVR screening failure is associated with increased cardiac death (HR 12 [1,51;95], p<0,019) and death for any causes (HR 17,5 [6,02;51], p<0,001). Conclusion(s) In the present experience, approximately 50% of patients screened for TMVR were accepted. The most frequent reasons for screening failure were anatomical issues. With a baseline similar clinical profile, treatment with TMVR provided significant 1-year survival and symptoms improvement compared to those of patients refused, whose prognosis is indeed remarkably poor. These data underline the importance of proper patient selection for TMVR to achieve good outcomes but also the need for technological improvement of devices to expand the proportion of patients who can be treated. Given the small numbers currently available, more data are needed to confirm the present findings, which must be considered hypothesis-generating.Figure 1Figure 2