BACKGROUND: Optimal treatment of chronic ischemic mitral regurgitation (CIMR) remains elusive. We compared septal-lateral annular cinching (SLAC) versus posterior papillary muscle adjustment (PAP), in reducing the degree of CIMR.
METHODS: Sheep underwent placement of radiopaque markers on the mitral annulus (MA) and posterior papillary muscle (PPM). A trans-annular suture was anchored to the mid-septal MA and externalized to a tourniquet through the mid-lateral MA. Another suture was anchored to the PPM, passed through the MA near the posterior commissure, and externalized on a tourniquet. After 7 days, Baseline 3-D marker data were obtained videofluoroscopically before snare occlusion of obtuse marginal coronary arteries. After 7 weeks, animals developing CIMR assessed by TEE (N=9) were re-studied before and after pulling SLAC or PAP sutures. End-systolic septal-lateral (S-L) annular diameter and apical and lateral displacement of PPM from the mid-septal annulus were computed (PPM_apical and PPM_lateral).
RESULTS: Table. Mean±SD.
CONCLUSIONS: CIMR caused MA S-L dilation and PPM displacement laterally and towards the annular plane. SLAC undersized the S-L dimension and corrected lateral PPM displacement, perhaps indirectly by dragging the PPM closer to the septum, and corrected MR. PAP reduced S-L diameter but, surprisingly, did not change lateral PPM displacement or reduce MR. Repair techniques, whether annular or subvalvular, which address both MA S-L dilation and lateral (but not apical) PPM displacement may be more successful at reducing CIMR.

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