An Imaging-Based Marker to Refine Risk Stratification for Transcatheter Mitral Valve Replacement.

: The Tendyne™ transcatheter heart valve (THV) system is a promising option for high-risk patients with severe mitral regurgitation (MR) who are ineligible for surgery or transcatheter edge-to-edge repair (TEER). As most fatal complications occur within the first 90 days, this study aimed to identify anatomical predictors of in-hospital mortality after transcatheter mitral valve replacement (TMVR). In this subanalysis of the TENDER registry, data from 110 patients who underwent TMVR across 26 centers between January 2020 and June 2022 were evaluated. Preprocedural imaging parameters were analyzed, including transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and cardiac 4D computed tomography (CT). We identified LVEDDi as a significant predictor of in-hospital mortality ( = 0.022), with lower values in non-survivors (26.42 ± 3.76 mm/m) than in survivors (30.37 ± 5.58 mm/m). Both indexed and absolute LVEDDi predicted in-hospital complications ( < 0.001 and = 0.008). In multivariate analysis, LVEDDi ( = 0.048; OR = 0.856) and STS score ( = 0.038; OR = 1.114) remained independent predictors of in-hospital mortality. In an extended model, only LVEDDi persisted as a significant predictor ( = 0.007), highlighting its robustness. : This analysis identified a small LVEDDi as a novel, clinically relevant risk factor in TMVR and showed its added value alongside conventional markers. Its easy calculation supports incorporating LVEDDi thresholds into screening to improve patient selection and outcomes.