Ischemic mitral valve prolapse: mechanisms and implications for valve repair

OBJECTIVE: The aim of this study was to assess the mechanisms of prolapse in ischemic mitral valve regurgitation (MR) and the techniques of valve repair. METHODS: Out of 121 patients operated upon for ischemic MR, a prolapse was present in 44 patients (36.4%). The operation was performed emergently in four cases (9.1%) and electively in 40 patients (90.9%). Fifteen patients (34.1%) were operated upon within 60 days following acute myocardial infarction. RESULTS: The diagnosis of prolapse had been overlooked by echography in five cases (11.4%). A commissural area was involved as the site of prolapse in 31 cases (70.4%). The mechanism of prolapse was a papillary muscle (PM) lesion in 38 cases (86.4%) (anterior PM: n=8, posterior PM n=36) or a chordal lesion in six cases (13.6%). PM injury was elongation (n=16), or rupture (total n=1, partial n=21, incomplete n=4). The operative technique was mitral valve repair with Carpentier's techniques in 42 cases (95.5%) or replacement in two cases (4.5%). Hospital mortality was 11.4% (n=4). The mean follow-up was to 44.7+/-29.6 months. Overall survival and freedom from reoperation were 68.3+/-9.0 and 89.9+/-5.7% at 5 years, respectively. Freedom from MR equal or > grade 2 was 69.7+/-9.5% at 5 years. CONCLUSIONS: The mechanisms of ischemic mitral valve prolapse were variable and tightly linked to the PM anatomy. A reliable mitral valve repair could be achieved in most cases with acceptable mid-term results.