Predictive factors for persisting excess symptoms following transcatheter edge-to-edge repair for degenerative mitral regurgitation: Results of the worldwide, multicenter PRIME-MR registry

Background Residual mitral regurgitation (MR) has emerged as a robust predictor of adverse outcomes following mitral valve transcatheter edge-to-edge repair (M-TEER) for primary MR (PMR). While M-TEER effectively reduces MR severity, a subset of patients continues to experience a substantial symptomatic burden, as indicated by New York Heart Association (NYHA) Class III or IV status at discharge. Identifying factors associated with persistent symptoms is essential to refine patient selection and optimize post-procedural management strategies. Leveraging data from the multicenter PRIME-MR registry, this study aims to identify key predictors of ongoing symptomatic excess following M-TEER. Methods PRIME-MR is a retrospective, investigator-initiated, multicenter registry encompassing patients who underwent M-TEER for clinically relevant PMR at 24 high-volume centers from 2008 to 2022. After excluding cases with incomplete data, 888 patients were eligible for analysis. Symptomatic status at discharge classified patients into NYHA Class I/II or Class III/IV, with the latter indicating persistent symptoms. The primary composite endpoint included all-cause mortality and rehospitalization. Results Of the 888 patients analyzed, 742 (83.6%) achieved NYHA Class I/II status at discharge, while 146 (16.4%) remained symptomatic in NYHA Class III/IV. Age and sex distributions were comparable between these groups. However, patients with persistent symptoms had higher baseline NYHA classes (NYHA Class ≥III: 93.8% vs. 81.6%; p<0.001) and a lower median 6-minute walk distance (158 m [IQR 40, 270] vs. 252 m [137, 329]; p=0.0062). Baseline MR severity, measured by effective regurgitant orifice area, was similar across groups (median EROA 0.4 mm² [0.3, 0.6]; p=0.81). Nonetheless, those with persistent symptoms had a significantly higher prevalence of mitral annular calcification (7.1% vs. 2.7%, p=0.023) and a smaller mitral valve orifice area (4.0 cm² [3.1, 5.2] vs. 4.9 cm² [4.0, 5.8]; p=0.001). At discharge, patients with persistent symptoms more frequently exhibited moderate or greater residual MR (56.6% vs. 28.9%; p<0.001), correlating with increased rates of the primary composite endpoint of all-cause mortality and rehospitalization (log-rank p<0.0001, Figure 1). Conclusion A distinct subset of patients undergoing M-TEER for primary MR remains symptomatic, particularly those with mitral annular calcification and smaller mitral valve orifice areas. This group was at significantly higher risk for mortality and rehospitalization. These findings highlight the need for tailored risk assessment and targeted management strategies to optimize outcomes in high-risk patients.