Impact of residual mitral regurgitation after MitraClip implantation

MitraClip (MC) is an alternative treatment for mitral regurgitation (MR). Although residual MR is common after MC, little was known about the impact of residual MR after MC.

We examined 255 consecutive patients who underwent MC. The primary endpoint was the composite endpoint including all-cause death, left ventricular (LV) assist device, and mitral valve surgery.

Procedure failure defined as unsuccessful MC implantation (n=6) and residual MR ≥3+ (n=19) was associated with worse outcomes including the primary endpoint and all-cause death than those with acute procedure success (APS) defined as residual MR 2+ (n=125) or 1+ (n=105). Among patient with APS, background characteristics including age, MR etiology, heart failure severity, and LV function were not different. Although MR grade and NT-pro BNP level at 6months after MC were higher in patients with residual MR 2+, there was no significant difference in the incidence of the primary endpoint and all-cause death. Subanalysis showed that the primary endpoint occurred more frequently in patients with MR 2+ in patients with LV ejection fraction ≤40%, chronic kidney disease, and baseline NYHA-class IV.

Procedure failure was associated with adverse outcomes after MC. Among patients with APS, residual MR 2+ was not significantly associated with overall worse outcomes than residual MR 1+. However, residual MR 2+ was associated with poorer prognosis in patients with impaired LV function, renal dysfunction, and severe heart failure, suggesting that the optimal endpoint of MC procedure should be individualized according to each patient's baseline characteristic.