Characteristics and Outcomes of Patients Ineligible for Transcatheter Mitral Valve Replacement (TMVR): Implications for Future Device Innovation

OBJECTIVES: Due to high rates of transcatheter mitral valve replacement (TMVR) screening failure, a substantial proportion of patients with severe mitral regurgitation (MR) remains on optimal medical treatment (OMT) only. Data on outcomes of these patients ineligible for mitral interventions are scarce. This study aimed to assess characteristics and outcomes of severe MR patients treated medically following TMVR screening failure.

METHODS: From 2016-2020, a total of 111 patients with severe MR underwent screening for TMVR. Screening failure occurred in 66 cases. Among these, 30 patients were treated with OMT only. Characteristics of these patients were analyzed, Kaplan-Meier estimates calculated, and univariate regression analysis performed. Median follow-up time was 2.26 years (95% confidence interval, 1.24-3.25).

RESULTS: Anatomical reasons for screening failure in the study cohort (n = 30) were left ventricular (LV) restraints, risk of LV outflow tract obstruction, mitral annulus calcification, and sizing issues. Median ejection fraction was 56.0% (interquartile range, 38.8%-60.0%). Concomitant tricuspid regurgitation and severe pulmonary hypertension were present in 36.7% and 46.2%, respectively. Intercommissural diameters ranged from 22.5-52.0 mm. Mortality was 23.6% after 6 months and 35.7% after 1 year. Factors associated with mortality were female sex, MR severity, ischemic MR, high N-terminal pro-brain natriuretic peptide levels, and small annulus diameters.

CONCLUSIONS: Despite growing experience with TMVR, the subset of MR patients anatomically eligible for TMVR is small and many patients are treated medically. Mortality in these patients remains high, underlining an unmet need for adequate therapeutic alternatives. TMVR devices adapting to broader annular size ranges with smaller ventricular profiles might fill this gap.