Evaluation of the Impact of Transmitral Mean Gradient Elevation after Transcatheter Mitral Valve Implantation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Transcatheter mitral valve implantation (TMVI) has emerged as an alternative to surgery in high risk patients with failing mitral bioprosthesis (valve-in-valve) or annuloplasties (valve-in-ring). The presence of an elevated mean gradient > 5mmHg after the procedure has been defined as an unsuccessful procedure but the impact and outcomes of an elevated mean gradient after TMVI have not been studied. Materials and methods 103 patients undergoing TMVI from 2010 to 2020 were included. Patients were classified in three groups according to mean gradient after the procedure: Group 1< 5mmHg, Group 2 between 5 and 10mmHg and Group 3 > 10mmHg. Results The median age was 71 (52.5–81.5) years. Indications for TMVI were bioprosthesis failure in 67 patients (65%) and ring annuloplasty failure in 36 patients (35%). 84 (81.6%) patients were in NYHA class III or IV. 42 patients were in group 1, 51 in group 2 and 10 in group 3, without any difference in baseline characteristics or procedural findings. At 30 days, the rates of all-cause mortality (respectively 2,6%, 0% and 0%, p = 0,66), rehospitalization for heart failure (respectively 8,4%, 7,7% and 8,4%, p = 0,89), paravalvular leak (10,3%, 27,7%, 22,2%, p = 0,33), LVOT obstruction (respectively 6,3%, 8,2% and 10%, p = 0,99) or valve thrombosis (respectively 7,7%, 4,3% and 0%) were similar in the three groups. At a median follow up of 2 years, 27 patients have died with a cumulative rate of all-cause mortality at 1 and 2 years of 21.5% and 38.1% respectively. The presence of an elevated mean gradient was not associated with increased risk of mortality (HR=1,11, (95% CI [0,93, 1,31]), p = 0,25) An improvement of NYHA class was observed in the three groups without any difference between the groups. Median systolic pulmonary arterial pressure significantly improved in group 1 (from 53mmHg (30–90) in baseline to 45mmHg (25–60), p = 0.005) and 2 (from 55mmHg (30–112) in baseline to 40mmHg (30–75), p = 0.004)) but not in group 3. Conclusion An elevated mean gradient post-TMVI had no impact on cardiovascular outcomes up to 2 years. Further studies with longer follow up are necessary.