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.