The Impact of Intraoperative Residual Mild Regurgitation Following Repair of Degenerative Mitral Regurgitation

Structured Abstract Objective(s) During degenerative mitral repair surgeons must decide if further repair is warranted for residual mild mitral regurgitation. We examined the incidence of mild mitral regurgitation, late echocardiographic and clinical outcomes, and influence of surgical experience in decision making. Methods From 04/2004 through 06/2018, 1155 patients had repair out of 1195 pure degenerative patients (97% repair rate). Propensity-score matching was performed between patients with trace/no (No) vs. Mild residual mitral regurgitation. Late echocardiographic outcome and freedom-from-reoperation were compared using competing risks models. A comparison of outcomes of the referent surgeon (89.8% of repairs) vs. all other surgeons was performed. Results Mild mitral regurgitation was present in 73 (6%) of patients. PS-matched analyses compared 69 Mild mitral regurgitation patients to 198 with No mitral regurgitation. Late ≥ moderate mitral regurgitation was higher for those with Mild mitral regurgitation vs. No mitral regurgitation (17% vs. 7% p=0.033) as was late ≥ moderate-severe mitral regurgitation (6% vs. 1%, p=0.016). Ten-year freedom from reoperation was low in both groups (99.5% No vs. 96.9% Mild; p=0.10). The referent surgeon had fewer patients with mild residual mitral regurgitation (6% vs. 11%, p=0.027) and less progression of mitral regurgitation compared to other surgeons (late ≥ moderate MR 6% vs. 15%, p=0.002). Conclusions Residual mild mitral regurgitation was uncommon, and late progression to ≥ moderate 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.