Expanding TMVR Suitability with a Transseptal Left Atrial Fixation Device: A CT-based Eligibility Analysis

Background Transcatheter mitral valve replacement (TMVR) adoption is limited by high screening failure rates, mainly due to anatomical constraints such as neo-left ventricular outflow tract (neo-LVOT) obstruction risk. A novel transseptal TMVR system with left atrial (LA) fixation may expand anatomical eligibility while avoiding LVOT compromise. Purpose To assess anatomical eligibility for a transseptal TMVR system with LA fixation in patients with relevant mitral regurgitation (MR) previously screened for TMVR and to evaluate its potential impact on overall TMVR eligibility. Methods All consecutive patients with relevant MR referred for TMVR evaluation were prospectively enrolled in a single-center registry. Patients screened for dedicated TMVR devices with full cardiac cycle CT imaging were included. Retrospective eligibility for the LA fixation system was assessed using manufacturer-recommended CT thresholds. Patients were classified as Screen Pass or Screen Failure. Reasons for ineligibility were analyzed, and clinical, echocardiographic, and CT parameters compared. Overall impact was determined by comparing real-world acceptance rates (sub-valvular TMVR devices only) with the expected screen pass rate using the LA fixation system. A subgroup analysis included patients with prior screening failure due to high neo-LVOT obstruction risk. Results Among 211 screened patients, 24 were excluded due to incomplete CT imaging; 187 were analyzed (mean age 76.3 years [IQR 73–81], 55.6% male, ejection fraction 45.8% [IQR 34–57], 48.9% primary MR). CT-based evaluation showed that 112 patients (59.9%) fulfilled eligibility criteria (Screen Pass), whereas 75 (40.1%) did not (Screen Failure). Main reasons for screening failure were high LA volume change (N=36, 48.0%), mitral annular size (N=22, 29.3%), LA width (N=19, 25.3%; 17 too small, 2 too large), unfavorable LA tilt (N=16, 21.3%), excessive LA height (N=15, 20.0%), and small left ventricular volume (N=4, 5.3%). Screen Pass patients were more often male (57.1% vs. 53.3%) and had higher atrial fibrillation prevalence (82.14% vs. 57.33%). Secondary MR predominated in the Screen Pass group (N=72, 66.06%), whereas primary MR was more frequent in Screen Failure patients (N=43, 58.90%). Comparing real-world acceptance for sub-valvular TMVR devices (33.6%) with the expected screen pass rate for the LA fixation system (59.9%) suggested a potential overall eligibility increase of 26.3%. In patients with prior screening failure due to high neo-LVOT obstruction risk, screen pass and failure rates were 42.9% and 57.1%, respectively. Conclusion Integrating a transseptal TMVR system with LA fixation into the screening portfolio may substantially expand TMVR eligibility, particularly in patients at high risk of neo-LVOT obstruction, as the device spares the LVOT. Further studies should evaluate whether treatment improves prognosis in severe MR.