Treatment of Failed Mitral Valve Bioprostheses or Repairs: Transcatheter Mitral Valve-in-Valve/Valve-in-Ring Versus Redo Surgical Mitral Valve Replacement

Background/Objectives: Transcatheter mitral valve-in-valve (ViV) and valve-in-ring (ViR) procedures have emerged as alternative treatment options for failed mitral valves following prior bioprosthetic replacement or ring annuloplasty. However, redo surgical mitral valve replacement (redo-MVR) remains the standard therapy despite its perceived higher procedural risk. This study aimed to descriptively compare short- and long-term outcomes of ViV/ViR and redo-MVR. Methods: We retrospectively included patients older than 60 years who underwent treatment of failed mitral valve bioprostheses or repairs between 2000 and 2022 (n = 30; ViV/ViR cohort: 2008–2022). Patients treated with ViV/ViR (n = 15) were compared with those undergoing redo-MVR (n = 15). Endpoints were reported according to Mitral Valve Academic Research Consortium (MVARC) criteria. Technical, device, and procedural success were defined according to the MVARC criteria and applied identically to both groups. Owing to the small sample size and substantial baseline differences, this study is descriptive and hypothesis-generating. Results: Patients in the ViV/ViR group were significantly older than redo-MVR patients (76.9 ± 5.8 vs. 68.0 ± 8.4 years, p < 0.001). EuroSCORE II did not differ significantly between groups. Thirty-day mortality was comparable, with one death in the ViV/ViR group and none after redo-MVR (6.7% vs. 0%, p = 1.00). Device success at 30 days was significantly higher after redo-MVR compared with ViV/ViR (86.7% vs. 40.0%, p = 0.02). Neurological events were rare and similar between groups. Degenerated bioprostheses were more frequent in the ViV/ViR group (86.6%), whereas prior annuloplasty ring implantation predominated in redo-MVR patients (80.0%, p < 0.01). Pre-procedural and discharge mitral valve gradients were higher in ViV/ViR patients. Implanted valve size was smaller in the ViV/ViR cohort (28.2 ± 1.4 vs. 29.5 ± 1.8 mm, p = 0.03). Conclusions: In this small, retrospective, single-center cohort with substantial baseline differences (e.g., age), 30-day mortality was low in both groups. Device success was higher after redo-MVR, mainly because of higher postoperative gradients after ViV/ViR. These findings are descriptive and hypothesis-generating and do not constitute evidence of comparative treatment effectiveness. Both approaches may be considered complementary options guided by a multidisciplinary heart team.