Standardized subannular repair for type IIIb functional mitral regurgitation in a minimally invasive mitral valve surgery setting†

OBJECTIVES: Subannular repair techniques in addition to undersized ring annuloplasty have been developed to address high mitral regurgitation (MR) recurrence rates after mitral valve repair in type IIIb MR. We compared the results of annuloplasty with simultaneous standardized subannular repair versus isolated annuloplasty, focusing on the periprocedural outcomes of minimally invasive procedures. METHODS: A consecutive series of 108 patients with type IIIb functional MR with severe signs of bileaflet tethering underwent an annuloplasty + subannular repair (group A; n = 60) versus isolated annuloplasty (group B; n = 48). The primary end point of this prospective, parallel cohort study was death or recurrent MR >2, 1 year postoperatively. The secondary end points were survival and clinical outcomes, with special regard for the minimally invasively treated subgroups. RESULTS: Duration of surgery, cardiopulmonary bypass time and aortic cross-clamp time were comparable between both study groups. Procedural outcomes as well as echocardiographic outcome parameters were similar and independent of access (fully endoscopic versus full sternotomy). At the 12-month follow-up, death or MR >2 occurred in 3.3% (2/60) of patients in group A vs in 20.8% (10/48) of patients in group B (P = 0.037). The overall mortality rate during the follow-up period was 1.7% (1/60) in group A vs 12.5% (6/48) in group B (P = 0.041). CONCLUSIONS: Standardized realignment of papillary muscles is feasible and reproducible via a minimally invasive approach, resulting in excellent periprocedural outcomes, and has a clear potential to significantly decrease MR recurrence and improve 1-year outcomes compared to isolated annuloplasty.