This study is a single institution, multi-surgeon review of consecutive patients undergoing surgical mitral valve (MV) repair for type II degenerative disease; They included 1155 of 1195 patients with pure degenerative disease underwent repair (97% repair rate). A comparison of outcomes of the referent surgeon (89.8% of repairs) with all other surgeons was performed.

Of 1155 patients who underwent MV repair, 1082 (94%) had none/trivial residual mitral regurgitation (MR) on intraoperative transesophageal echocardiogram [TEE], 73 (6%) had mild residual MR, and 0 had moderate or greater residual MR.

The referent surgeon performed 1037 (90%) of the repairs, and those results were compared with those for all other surgeons (n= 118). On predischarge and late echocardiograms, intermediate reports were upgraded so that trivial to mild MR was in the mild (1+) MR group, and mild to moderate MR was in the moderate 2+) MR group. Moderate to severe MR was graded 3+, and severe MR was graded 4+.

Late moderate or greater mitral regurgitation was higher in those with mild mitral regurgitation than in those with no mitral regurgitation (17% vs 7%, P= 0.033), as was late moderate- severe or greater mitral regurgitation (6% vs 1%, P= 0.016)

The referent surgeon had fewer patients with mild residual mitral regurgitation (6% vs 11%, P= 0.027) and less progression of mitral regurgitation compared with other surgeons (late moderate or greater mitral regurgitation 6% vs 15%, P= 0.002).

There were no significant differences in the size of annuloplasty ring, the type of repair technique, and primary versus repeat sternotomy, and the need for re-cross clamp was no longer different. Overall, patients in the mild MR group were still more likely to develop moderate or more MR during follow-up compared with the no MR group (P<.001) Freedom from MV reoperation at 5 years was 99.5% with no MR and 96.9% in patients with mild MR, whereas at 10 years the corresponding values were 99.5% and 96.9%, respectively. There was no significant difference in all-cause late mortality.

An infrequent topic that is reported is 66 patients with mild residual MR after repair, 24% got better with time and turned to no MR at all, they justify this finding by mentioning that some patients with post-pump reduced left ventricular function had MR resolution over time as the ejection fraction improved, perhaps indicating better coaptation with improved contractility.

The authors' conclusion is that the residual mild mitral regurgitation was uncommon, and late progression to moderate or greater mitral regurgitation was rare and never led to late mitral reoperation. Experienced surgeons may be better able to determine repairs likely to remain stable, and most mild residual mitral regurgitation does not require re-repair.