Failure of reduction annuloplasty for functional ischemic mitral regurgitation

The standard treatment for functional ischemic mitral regurgitation (FIMR) is revascularization and reduction annuloplasty. Although the immediate results are excellent, some patients develop recurrent mitral regurgitation (MR) at mid-term follow up. The study aim was to identify possible preoperative echocardiographic parameters that might predict the risk of recurrent FIMR.

From 124 consecutive patients who underwent revascularization and ring annuloplasty, 48 were selected if they: (i) had a complete preoperative and follow up transthoracic echocardiogram; and (ii) left the operating room with grade 1+ MR. Those patients with moderate or greater late MR were classified as having significant recurrent FIMR (MR group), and those with mild or no MR were classified as no significant FIMR (No-MR group). Left ventricular ejection fraction (LVEF), left ventricular (LV) sphericity, percentage MR jet area, mitral valve tenting area, mitral valve coaptation height, papillary muscle (PM) tethering distance, PM depth, and PM angle were measured by echocardiography preoperatively and at mid-term follow up.

No preoperative differences were found between groups except in posterior PM depth and PM angle. The posterior PM depth and angle in the MR group were significantly smaller than in the No-MR group. In the No-MR group, the posterior PM tethering distance decreased and the PM angle increased significantly with decreasing LV sphericity. In contrast, in the MR group, posterior PM tethering distance, PM depth, and PM angle were unchanged, and the anterior PM depth and PM angle decreased significantly with decreasing LVEF.

FIMR is primarily due to PM displacement, and posterior PM relocation is especially important. Ring annuloplasty does not protect against recurrent FIMR in patients with severe outward displacement of the posterior PM. The severity of posterior PM displacement might be a predictor of ring annuloplasty failure.