Mechanism of and Risk Factors for Reoperation After Mitral Valve Repair for Degenerative Mitral Regurgitation

BACKGROUND: We reviewed our 20-year experience of mitral valve (MV) repair for degenerative mitral regurgitation (MR) and analyzed the mechanisms and risk factors of reoperation. METHODS AND RESULTS: Six hundred and fifty-four patients who underwent MV repair for degenerative MR between 1991 and 2010 were retrospectively reviewed. The mean follow-up duration was 7.5 ± 4.9 years. Late echocardiography was obtained at a fixed schedule. Standard procedures for MV repair were resection and suture for posterior prolapse, artificial chordal reconstruction for anterior prolapse and a combination of them for prolapse of both. Ring annuloplasty was performed in most cases. We encountered 2 early and 23 late reoperations. Fifteen (60%) were valve-related failure, 9 (36%) were procedure-related failure and 1 was unknown. Valve-related failure was characterized with recurrence of MR due to new prolapse region and progression of mitral stenosis due to leaflet thickening. For them, reoperation was performed at 7.6 years and 14.3 years after the initial operation, respectively. Multivariate analysis identified preoperative left ventricular diastolic diameter and residual regurgitation at discharge as risk factors for reoperation. CONCLUSIONS: Valve-related failure occurred late due to slow progression of degenerative disease. Long-term follow-up after surgery is mandatory. Given that progression and severity of MR were identified as risk factors for reoperation, early surgical intervention is desirable for degenerative MR.