Mitral valve-in-valve and valve-in-ring procedures: Midterm outcomes in a French nationwide registry

Objectives Report contemporary outcomes in patients included in the Mitragister registry and treated with transcatheter mitral valve implantation for failed surgical annuloplasty rings or deteriorated bioprosthesis. Background Midterm survival rates have been reported, but little is known about contemporary morbimortality endpoints. Methods The primary safety outcome was the technical success rate. The primary efficacy composite endpoint was a composite of cardiovascular mortality and heart failure hospitalizations. Results From 2016 to 2021, 102 patients (median age: 81 [74;84] years, 61% female, Euroscore II 11.0% [7.8;16.0]) undergoing valve-in-valve (ViV; n = 89) or valve-in-ring (ViR; n = 13) procedures were consecutively included. At baseline, ViR group patients had worse left ventricular ejection fraction (50% vs. 60%; p = 0.004) and more frequently severe regurgitation (46% vs. 15%; p = 0.014). The primary safety outcome was 95%: 77% and 98% in the ViR and ViV populations, respectively, (p = 0.014). At intermediate follow-up (6-12 months) clinical improvement was notable, 88% of the patients were in NYHA class <= II (vs. 25% at baseline; p < 0.001). At a mean follow-up of 17.1 +/- 11.0 months, the primary efficacy composite reached 27%. By multivariate analysis, paravalvular leak (PVL) was the only independent predictor (hazard ratio: 2.39, 95% confidence interval: 1.08-5.29; p = 0.031) while ViR was not found statistically associated (p = 0.456). Conclusions This study confirms the safety and efficacy of the mitral ViV procedure. ViR patients appear at higher risk of procedural complications. The presence of PVL could be associated with markedly worse midterm prognosis. Whatever the intervention, procedural strategies to reduce PVL incidence remain to be assessed to prevent latter adverse outcomes.