Incidence and standardised definitions of mitral valve leaflet adverse events after transcatheter mitral valve repair: the EXPAND study.

Background: An independent panel of experts reviewed all investigator-reported cases of mitral valve leaflet adverse events (LAE) after MitraClip NTR/XTR in the EXPAND study.

Aims: We aimed to report the findings of the expert panel and standardise definitions for LAE.

Methods: Standard definitions for different types of LAE were formulated and events adjudicated after detailed review by the expert panel.

Results: Enrolling centres reported LAE in 35 cases, 11 leaflet injuries (9 tears, 2 perforations) and 24 single leaflet device attachment (SLDA). The panel confirmed LAE in 20 cases (2.0% incidence), 18 patients had SLDA and 4 had leaflet injury (2 cases had both SLDA and injury). Leaflet injury occurred during device implant and resulted in surgical valve replacement or death. SLDA-alone events were identified during implant (n=2), pre-discharge (n=7) or at 30 days of follow-up (n=7) and were resolved (≤2+ residual MR) with additional clips in 75% of cases.

Conclusions: Mitral valve repair with MitraClip NTR/XTR is safe. The rate of LAE is lower than previously reported using older-generation devices. The proposed definitions and findings will help to differentiate leaflet injury from inadequate leaflet insertion and SLDA and provide guidance for consistent diagnosis of LAE post MitraClip implantation.