Transapical mitral valve-in-ring implantation: Results of the real-world European Tendyne valve-in-ring registry

Abstract Objectives Mitral regurgitation (MR) is commonly treated with ring-based annuloplasty. In case of recurrent MR, re-do operations are often denied due to high risk. Transcatheter valve-in-ring (V-i-R) procedures offer an alternative. This study assessed the feasibility and outcomes of using the transapical, repositionable Tendyne valve for off-label mitral V-i-R procedures, as an alternative to balloon-expandable valves like SAPIEN, which face limitations such as paravalvular leakage and LVOT obstruction. Methods The TEND-RING registry is a retrospective, international study with prospective follow-up, including 16 high-risk patients from eight European centers who underwent Tendyne V-i-R procedures between 2017 and 2024. Procedural, 30-day, and long-term outcomes were analyzed. Results Patients were elderly (median age 79.5), predominantly male (81%), with significant comorbidities (STS Risk of Mortality 5.6%, 4.4–7.2%) and severe MR (3 + /4 +). Procedural success was 100%, with no LVOT obstruction or device embolization. MR was reduced to mild or none in all patients. 30-day mortality was 6.3%. Over a median 11-month follow-up, five deaths occurred (31.3%), three from cardiovascular causes (18.75%). Surviving patients showed sustained MR reduction and improved symptoms (89% in NYHA I/II). Ring size analysis suggested a minimum of 36 mm for rigid/semi-rigid rings, while flexible bands allowed successful implantation in sizes as small as 30 mm. Conclusions Tendyne V-i-R procedures are technically feasible, effective, and safe in selected high-risk patients with recurrent MR. Ring size thresholds identified may guide patient selection and procedural planning in future interventions.