# Clip opening while locked after transcatheter edge-to-edge mitral valve repair with different onset times: a case series

## TL;DR

This case series reports two instances of clip opening while locked after a heart valve repair procedure using the MitraClip G4 system.

## Contribution

The paper presents the first reported cases of COWL during the acute phase with the MitraClip G4 system.

## Key findings

- COWL occurred in two cases at different times after the procedure.
- An additional XT system was successfully used to address mitral regurgitation caused by COWL.
- Operator experience and device generation are linked to reduced complication rates.

## Abstract

Transcatheter edge-to-edge mitral valve repair is now available in many countries and has achieved favourable therapeutic outcomes. However, there have been no reported cases of clip opening while locked (COWL) during the acute phase using the MitraClip G4 system (Abbott, Abbott Park, IL, USA).

We present two cases of COWL occurring at different phases: one immediately after clip release and the other 2 days post-procedure. In both cases, the initial treatment involved the use of the XTW system. Subsequently, an additional XT system was deployed for the deterioration of mitral regurgitation caused by COWL, without any complications.

The MitraClip G4 system offers four size variations, providing a larger grasping area and increased flexibility for accessing complex lesions. Furthermore, the complication rate decreased with increasing operator experience and device generation. However, it has been reported that COWL can occur after the clip is deployed during TEER. Although the mechanism of COWL is unclear, the nature and mobility of the valve leaflets and the product specificity of the MitraClip may be involved.