The Relationship between the Magnitude of Reduction in Mitral Regurgitation Severity and Left Ventricular and Left Atrial Reverse Remodeling after MitraClip® Therapy
Background—MitraClip has been shown to reduce mitral regurgitation (MR) severity safely but to a lesser degree than surgery. No data exist on the magnitude of MR reduction necessary to reverse left ventricular (LV) and left atrial (LA) dilation in patients with severe MR. Therefore, an analysis was performed to evaluate the relationship between MR reduction and LV and LA volumes after MitraClip therapy.
Methods and Results—A total of 801 patients treated with MitraClip and 80 patients treated surgically were included. All patients had severe (3-4+) MR. MR severity, LV volumes at end-diastole (LVEDV) and end-systole (LVESV) and LA volumes were measured at baseline, discharge, 30 days, 6 months and 1 year by an independent echocardiographic core laboratory. A linear repeated measures model was developed to determine the relationship between MR severity and time of measurement post-index procedure on longitudinal LV and LA volumes. Separate models were fit for functional (FMR) and degenerative MR (DMR). In both DMR and FMR, reduction in LVEDV was associated with degree of residual MR at 12 months (p<0.0001). LVESV was significantly reduced in FMR but not DMR. LA volumes were significantly related to reduction of MR severity in both groups.
Conclusions—Reduction of LVEDV and LA volumes, but not LVESV in DMR is consistent with correction of volume overload from primary MR. Reduction of all three measurements in FMR demonstrates reverse remodeling when MR severity is reduced to either 1+ or 2+ by MitraClip therapy.
Clinical Trial Registration Information—www.clinicaltrials.gov. Identifier: NCT00209274.
- Received January 2, 2013.
- Revision received July 30, 2013.
- Accepted August 5, 2013.