Mechanisms of mitral regurgitation after percutaneous mitral valve repair with the MitraClip

Aims: We sought to find the morphological mechanisms of recurrent mitral regurgitation (MR) after MitraClip procedure using 3D transoesophageal echocardiography (TOE).

Methods and results: Of 478 consecutive patients treated with the initial MitraClip procedure, 41 patients who underwent repeat mitral valve (MV) transcatheter or surgical intervention for recurrent MR were retrospectively reviewed. Using 3D-TOE, we investigated morphological changes of MV leading to repeat MV intervention. Aetiology of MR at the index intervention was primary in 24 (59%) and secondary in 17 (41%) patients. In the primary MR group, worsening leaflet prolapse at the clip site caused recurrent MR in 12 (50%) patients, while 7 (29%) patients had a leaflet tear at the clip site. Acute single leaflet device detachment was seen in four patients and one patient had recurrent MR between the plug and the clip. In secondary MR, left ventricular (LV)/left atrial dilation caused recurrent MR in 13 (76%) patients. Significant increase in the LV end-diastolic volume and tenting height were observed from post-index procedure to repeat intervention (LV end-diastolic volume; from 205 to 237 ml, P < 0.001, tenting height; from 0.8 to 1.3 cm, P < 0.001). New emergent leaflet prolapse/flail was seen in 3 (18%) patients, suggesting iatrogenic MR.

Conclusion: Mechanisms of recurrent MR after MitraClip procedure varied and depended on the underlying MV pathology: in primary MR, worsening mitral leaflet prolapse and in secondary MR, progressive LV dilation with worsening tenting were the main causes of recurrent MR.