Surgical redo versus transseptal or transapical transcatheter mitral valve-in-valve implantation for failed mitral valve bioprosthesis

Background: Redo surgical mitral valve replacement (SMVR) is the current standard of care for patients with failed bioprosthetic mitral valve (MV). Transcatheter mitral valve-in-valve replacement (TMViV) is arising as an alternative to SMVR in high risk patients. We sought to evaluate procedural safety, early and mid-term outcomes of patients who underwent transseptal TMViV (TS-TMViV), transapical TMViV (TA-TMViV), or redo-SMVR. Methods: We identified patients with failed bioprosthetic MV who underwent TS-TMViV, TA-TMViV, or SMVR at four Italian Centers. Clinical and echocardiographic data were codified according to Mitral Valve Academic Research Consortium definition (MVARC), except for significant valve stenosis. Results: Between December 2012 and September 27, 2019 patients underwent TS-TMViV, 22 TA-TMViV, and 29 redo-SMVR. TS-TMViV and TA-TMViV patients presented higher mean age and surgical risk scores compared with SMVR group (77.8 ± 12 years, 77.3 ± 7.3 years, 67.8 ± 9.4 years, p <.001; STS PROM 8.5 ± 7.2; 8.9 ± 4.7; 3.6 ± 2.6, p <.001). TS-TMViV procedure was associated with shorter intensive care unit time and total length of stay (LOS) compared with TA-TMViV and SMVR group. There were no differences in MVARC procedural success at 30-days (74.1, 72.7, and 51.7%, p =.15) and one-year all-cause mortality between groups (14.8, 18.2, and 17.2%, p = 1.0). MV mean gradient was similar between TS-TMViV, TA-TMViV, and SMVR groups at 30 days and 12 months. Conclusions: For the selected patients, TS-TMViV and TA-TMViV are to be considered a valid alternative to redo-SMVR with comparable 1-year survival. TS-TMViV is the less invasive strategy and has the advantage of shortening the LOS compared with TA-TMViV.