Does septal-lateral annular cinching work for chronic ischemic mitral regurgitation?

Objectives: Ring annuloplasty, the current treatment of choice for chronic ischemic mitral regurgitation, abolishes dynamic annular motion and immobilizes the posterior leaflet. In a model of chronic ischemic mitral regurgitation, we tested septal-lateral annular cinching aimed at maintaining normal annular and leaflet dynamics. Methods: Twenty-five sheep had radiopaque markers placed on the mitral annulus and anterior and posterior mitral leaflets. A transannular suture was anchored to the midseptal mitral annulus and externalized through the midlateral mitral annulus. After 7 days, biplane cinefluoroscopy provided 3-dimensional marker data (baseline) prior to creating inferior myocardial infarction by snare occlusion of obtuse marginal branches. After 7 weeks, the 9 animals that developed chronic ischemic mitral regurgitation were restudied before and after septal-lateral annular cinching. Anterior and posterior mitral leaflet angular excursion and annular septal-lateral and commissure-commissure dimensions and percent shortening were computed. Results: Septal-lateral annular cinching reduced septal-lateral dimension (baseline: 3.0 ± 0.2; chronic ischemic mitral regurgitation: 3.5 ± 0.4 [P < .05 vs baseline by repeated measures analysis of variance and Dunnett's test]; septal-lateral annular cinching: 2.4 ± 0.3 cm; maximum dimension) and eliminated chronic ischemic mitral regurgitation (baseline: 0.6 ± 0.5; chronic ischemic mitral regurgitation: 2.3 ± 1.0 [P < .05 vs baseline by repeated measures analysis of variance and Dunnett's test]; septal-lateral annular cinching: 0.6 ± 0.6; mitral regurgitation grade [0 to 4+]) but did not alter dynamic annular shortening (baseline: 7 ± 3; chronic ischemic mitral regurgitation: 10 ± 5; septal-lateral annular cinching: 6 ± 2, percent septal-lateral shortening) or posterior mitral leaflet excursion (baseline: 46° ± 8°; chronic ischemic mitral regurgitation: 41° ± 13°; septal-lateral annular cinching: 46° ± 8°). Conclusions: In this model, septal-lateral annular cinching decreased chronic ischemic mitral regurgitation, reduced annular septal-lateral diameter (but not commissure-commissure diameter), and maintained normal annular and leaflet dynamics. These findings provide additional insight into the treatment of chronic ischemic mitral regurgitation.