Transcatheter valve-in-valve implantation versus redo surgical mitral valve replacement in patients with failed mitral bioprostheses

Background: Data on the safety of valve-in-valve transcatheter mitral valve replacement (ViV-TMVR) compared with redo surgical mitral valve replacement (SMVR) in patients with a history of bioprosthetic mitral valve (MV) remain limited. Aims: We aimed to evaluate the in-hospital, 30-day and 6-month readmission outcomes of ViV-TMVR compared with redo-SMVR in a real-world cohort. Methods: The Nationwide Readmission Database was utilised, analysing data from 2015 to 2019. To determine the adjusted odds ratio (aOR), we used the propensity-matched analysis for major outcomes at index hospitalisation, 30 days, and 6 months during the episode of readmission. Results: A total of 3,691 patients were included, of these, 24.2% underwent ViV-TMVR and 75.8% under-went redo-SMVR. Patients undergoing ViV-TMVR were older with higher rates of comorbidities. The mean length of stay (15 days vs 4 days) and cost of hospitalisation ($76,558 vs $46,743) were signifi-cantly higher for redo-SMVR. The rate of in-hospital all-cause mortality was also significantly lower in ViV-TMVR (2.6% vs 7.3%). By contrast, 30-day all-cause mortality during the episode of readmission (aOR 1.01, 95% confidence interval [CI]: 0.40-2.55) and all-cause readmission rates (aOR 0.82, 95% CI: 0.66-1.02) were similar between both groups. The incidence of all-cause readmissions at 6 months (aOR 0.83, 95% CI: 0.65-1.05) and all-cause mortality during the episode of readmission at 6 months (aOR 1.84, 95% CI: 0.54-6.36) were also comparable. The utilisation of the ViV-TMVR procedure increased significantly during our study duration, from 5.2% to 36.8%, (ptrend<0.01). Conclusions: ViV-TMVR is associated with lower odds of in-hospital mortality, complications, and resource utilisation. The all-cause readmissions and 30-day and 6-month mortality during the episode of readmissions were comparable between both groups.