Etiologies and Impact of Exclusion Rates for Transcatheter Mitral and Tricuspid Valve Structural Heart Clinical Trials at a High-Volume Quaternary Care Hospital

Abstract

There are various devices under clinical investigation for transcatheter mitral valve intervention (TMVI) and tricuspid valve intervention (TTVI), but exclusion rates remain high. We aim to investigate exclusion rates for transcatheter mitral valve repair (TMVr), transcatheter mitral valve replacement (TMVR), transcatheter tricuspid valve repair (TTVr) and transcatheter tricuspid valve replacement (TTVR). There were a total of 129 patients who were referred to St. Francis Hospital & Heart Center valve clinic and completed screening between January 2021 and July 2022. Causes for exclusion were classified into 4 categories: patient withdrawal, anatomic unsuitability, clinical criteria and medical futility. Among 129 patients, the exclusion rates for TMVr, TMVR, TTVr and TTVR were 81%, 85%, 91% and 87%, respectively. Patient withdrawal and medical futility were leading etiologies for exclusion, followed by anatomical unsuitability. TMVr had the highest rate of patient withdrawal (64%), the lowest anatomic unsuitability (5%) due to short posterior leaflet length. Replacement interventions have higher anatomic unsuitability (33%) compared to repair interventions (17%) (p=0.04). Most exclusions of anatomic unsuitability was due to mitral stenosis or small annulus size for TMVR and large annulus size for TTVR. Fifty percent of exclusions from TTVr were due to presence of pacemaker/defibrillator leads. Among patients excluded from their respective trials, patients being referred for TMVr had the highest recurrent hospitalization and repair group had a higher mortality (p<0.01 and p=0.01, respectively). In conclusion, exclusion rates for TMVI and TTVI trials remain high due to various reasons, limiting patients’ enrollment and treatment. This supports the need for further device improvement or exploring alternative means of therapy.