Hypoplasia of the Posterior Leaflet as a Rare Cause of Congenital Mitral Insufficiency

Abstract

A rare case of congenital mitral insufficiency characterized by the hypoplasia of the posterior leaflet is reported. At operation, the mitral valve was successfully repaired by a ring annuloplasty, which created a satisfactory surface of coaptation between the anterior leaflet and the bulky posterior muscular structure. The presence of this posterior muscular structure represents a developmental arrest at the stage of conversion from muscular chordae and leaflets to thin connective structures.

Hypoplastic posterior mitral valve leaflet: A case report and review of the literature

“…They reported this congenital anomaly as a consequence of developmental arrest at the stage of chordae and leaflets conversion from muscular to thin connective structures. Muscular structure of the PML that has been reported in some pediatric cases will also accelerate the process of annular dilatation and development of mitral regurgitation …”

An Incomplete Heart with Incomplete Lungs

“…The final atrioventricular valves are derived entirely from endocardial cushion tissue 8 . This hypothesis has been previously supported by the presence of myocytes in biopsy specimens of the valvular remnants 2 …”

“…8 This hypothesis has been previously supported by the presence of myocytes in biopsy specimens of the valvular remnants. 2 Our patient has congenital hypoplasia of the right upper and middle lobes of the lungs in addition to valvular anomaly. In previous studies, connective tissue diseases and thoracic skeletal abnormalities have been found to be associated with congenital valvular anomalies.…”

“…Most commonly seen anomalies are congenital mitral stenosis, atresia of mitral valve, accessory valvular tissue, double‐orifice, and cleft mitral valves. Hypoplasia and agenesis of the valve is very rare, and to our knowledge, only a few cases of severe congenital hypoplasia and agenesis of the posterior mitral leaflet have been reported in literature 1–6 …”

“…tal hypoplasia and agenesis of the posterior mitral leaflet have been reported in literature. [1][2][3][4][5][6] Although the pathogenesis is not well known, a defect in the collagenization of the atrioventricular valves during embryogenesis has been blamed. During embryogenesis, the valvular primordia are replaced by the muscular tissue which, at a later stage, becomes collagenized into thin connective tissue structures.…”