Recurrent incompetence of repaired floppy mitral valves and the severity of myxomatous degeneration

The purpose of this study was to clarify whether or not severe myxomatous d egeneration impairs the stability of a repaired mitral valve after valve-co nservative surgery. A total of 21 patients who underwent successful valve-c onservative surgery for pure isolated mitral incompetence were classified i nto two groups, one comprising those with stable mitral valve function and the other comprising those who developed recurrent incompetence within 1 ye ar after surgery. The histological severity of myxomatous degeneration of t he mitral leaflet was compared between the two groups, based upon microscop ic observation and quantification of the myxomatous area in the fragment th at had been surgically excised From the floppy mitral leaflet during valve- conservative surgery. The degree of myxomatous degeneration of the surgical ly excised fragment was significantly higher in the "recurrent" group than in the "stable" group (P = 0.02). As a microscopically confirmed severely d egenerative myxomatous mitral valve may develop recurrent incompetence afte r valve-conservative surgery within a relatively short period, careful and regular follow-up is required.