Background: The majority of patients with degenerated surgical mitral bioprostheses or failed mitral valve repair are at high risk for re-surgery and therefore candidates for a percutaneous approach. Multi-center registries provide valuable information on the acute outcome of transcatheter mitral valve in valve (TMVIV) or valve-in-ring (TMVIR), but the average number of cases per center was limited (1 case per year) and the route of access was mainly transapical. Long-term data are rare. We report acute and long-term results of transseptal and transapical TMVIV or TMVIR from a single center.

Methods: Data from patients who received TMVIV or TMVIR between April 2014 to June 2021 were analysed according to MVARC (Mitral Valve Academic Research Consortium) definitions. Transvalvular gradients ³ 10mmHg were defined as a cut-off for mitral stenosis. 

Results: From 28 patients (mean age 73.7 ± 10.5 years, male 36%, NYHA III/IV 96%, Euroscore 28.56 ± 15%), who underwent TMVIV or TMVIR, 13 had a transapical (April 2014 to April 2016) and 15 a transseptal approach (April 2016 to June 2021). Mechanism of failure was stenosis (39% vs 0), regurgitation (33% vs 90%) and mixed (28% vs 10%) in TMVIV vs TMVIR, respectively. All patients except for one were followed clinically and echocardiographically for 1215 days (range 153 to 2765 days). In TMVIV device success was achieved in 89% and in 70% in TMVIR group. In TMVIV vs TMVIR groups 30-day all-cause mortality was 5.6% vs 30%, 30-day cardiovascular mortality was 0 vs 20%, 4-year all-cause mortality 17.6% vs 40% and 4-year cardiovascular mortality 5.6% vs 20%, respectively. All patients who died within 30 days had a transapical approach (1/5 in TMVIV, 3/8 in TMVIR). The mean transvalvular gradient in TMVIV decreased from 11.8 ± 4.6mmHg to 7 ± 2.9mmHg acutely and to 8.4 ± 3.1mmHg at follow up, moderate/severe mitral regurgitation (MR) was present at 12 patients at baseline, decreased to non/trace in all patients and remained so at follow up. In TMVIR moderate/severe baseline MR was reduced to mild in 70%, 1 patient underwent surgery due to severe residual insufficiency, 1 patient had moderate MR and in 1 patient the valve was not implanted due to severe left ventricular outflow tract obstruction. At follow up all TMVIR patients had none or mild MR.

Conclusions: Compared to transapical access the transseptal approach in TMVIV or TMVIR is associated with a lower 30-day mortality. The acute outcome of TMVIR patients is less favourable compared to TMVIV patients. Beyond 30 days the hemodynamic performance seems to be stable up to 4 years.