Association Between Clinical Trial Participation Status and Outcomes With Mitral Transcatheter Edge-to-Edge Repair

Clinical trials have demonstrated the efficacy and safety of mitral transcatheter edge-to-edge repair (M-TEER) for selected patients with severe mitral regurgitation. However, the generalizability of trial results to real-world patients remains uncertain. The authors aimed to compare baseline characteristics and in-hospital outcomes among trial participants with nonparticipants undergoing M-TEER. Using the National Inpatient Sample database years 2016-2020, M-TEER admissions were identified and categorized into trial participants vs none. We also identified a cohort of trial noneligible patients based on clinical exclusion criteria from pivotal trials. Multivariate regression analysis was performed to compare in-hospital outcomes. The primary outcome was in-hospital mortality, and secondary outcomes included in-hospital complications, length of stay, and hospitalization cost. Among 38,770 M-TEER admissions from 2016 to 2020, 11,450 (29.5%) were trial participants, 22,975 (59.3%) were eligible nonparticipants, and 2,960 (7.6%) were noneligible. Baseline characteristics and comorbidity profiles were mostly similar between trial participants vs eligible nonparticipants. In-hospital mortality (adjusted OR [aOR]: 0.98; 95% CI: 0.60-1.62), cardiogenic shock (aOR: 1.06; 95% CI: 0.80-1.42), mechanical circulatory support (aOR: 0.91; 95% CI: 0.58-1.41), mechanical ventilation (aOR: 1.03; 95% CI: 0.74-1.42), and conversion to mitral valve surgery (aOR: 1.08; 95% CI: 0.57-2.03) were not different between both groups. Conversely, M-TEER for noneligible patients was associated with higher rates of mortality (aOR: 6.27; 95% CI: 3.75-10.45) and complications. The majority of real-world M-TEER patients would have been eligible for clinical trial participation and had comparable clinical profiles and in-hospital outcomes to trial participants. However, noneligible patients had worse in-hospital outcomes compared with trial participants.