Mitral valve annuloplasty and anterior leaflet augmentation for functional ischemic mitral regurgitation: quantitative comparison of coaptation and subvalvular tethering.

OBJECTIVE: Although restrictive mitral annuloplasty (RMA) has been the preferred surgical treatment of functional ischemic mitral regurgitation (FIMR), some patients with severely dilated left ventricles will experience recurrent mitral regurgitation (MR). Consequently, new surgical strategies have been entertained to compensate for severely dilated ventricles by maximizing coaptation and reducing subvalvular tethering. Anterior leaflet augmentation (ALA) with mitral annuloplasty has been theorized to meet these goals. We compared the mechanistic effects of RMA and adjunct ALA in the setting of FIMR.
METHODS: Mitral valves were mounted in a clinically relevant left heart simulator. The tested conditions included control, FIMR, RMA, and true-size annuloplasty with either a small or large ALA. The A2-P2 leaflet coaptation length, MR, and strut and intermediary chordal forces were quantified. All repairs alleviated the MR. The coaptation length was significantly increased from FIMR to RMA, small ALA, and large ALA (P<.001). Between repairs, a large ALA created the greatest length of coaptation (P<.05). Tethering forces from the posteromedial strut chordae were reduced from the FIMR condition by all repairs (P<.001). Only a large ALA reduced the intermediate chordal tethering from the FIMR condition (P<.05).
CONCLUSIONS: A large ALA procedure created the greatest coaptation and reduced chordal tethering. Although all repairs abolished MR acutely, the repairs that create the greatest coaptation might conceivably produce a more robust and lasting repair in the chronic stage. A clinical need still exists to best identify which patients with altered mitral valve geometries would most benefit from an adjunct procedure or RMA alone.