Comprehensive Annular and Subvalvular Repair of Chronic Ischemic MR Improves Long-Term Results with Least Ventricular Remodeling
Background—Undersized-ring annuloplasty for ischemic mitral regurgitation (IMR) is associated with variable results and >30% MR recurrence. We tested whether subvalvular repair by severing second-order mitral chordae can improve annuloplasty by reducing papillary muscle tethering.
Methods and Results—Posterolateral MI known to produce chronic remodeling and MR was created in 28 sheep. At 3 months, sheep were randomized to sham surgery vs. isolated undersized annuloplasty vs. isolated bileaflet chordal cutting vs. the combined therapy (n=7 each). At baseline, chronic MI (3 months) and sacrifice (6.6 months), we measured LV volumes and ejection fraction (EF), wall motion score index (WMSi), MR Regurgitation fraction (MRRF) and vena contracta (VC), Mitral annulus area (MAA) and posterior leaflet (PL) restriction angle (PL to MAA) by 2D and 3D echo. All groups were comparable at baseline and chronic MI, with mild-moderate MR (MRVC 4.6±0.1mm, MRRF 24.2±2.9%) and MA dilatation (p<0.01). At sacrifice, MR progressed to moderate-severe in controls but decreased to trace with ring + chordal cutting vs. trace-mild with chordal cutting alone vs. mild-moderate with ring alone (MRVC 5.9±1.1mm in controls, 0.5±0.08 with both, 1.0±0.9 with chordal cutting alone, 2.0±0.7 with ring alone, p<0.01). Also, LVESV increased by 108% in controls vs. 28% with ring + chordal cutting, less than with each intervention alone (p<0.01). In multivariate analysis, LVESV and MAA most strongly predicted MR (r2=0.82, p<0.01).
Conclusions—Comprehensive annular and subvalvular repair improves long-term reduction of both chronic ischemic MR and LV remodeling without decreasing global or segmental LV function at follow up.
- Received May 16, 2011.
- Accepted October 5, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited