[Pitfalls in echocardiographic diagnosis of mitral bileaflet prolapse]

Preoperative echocardiography provides good planning information for successful repair of mitral valve regurgitation, but identifying the prolapse of both the anterior and posterior leaflets is sometimes difficult. To clarify the cause of this problem, preoperative echocardiographic findings and intraoperative observations of the prolapse were analyzed in 124 patients with non-rheumatic pure mitral regurgitation. In 48 patients with final diagnoses of bileaflet prolapse, 16 (33%) were considered to have only single leaflet prolapse before the operation. Anterior leaflet prolapse was overlooked in 14, and prolapse of either of its commissural segments was the least detectable by echocardiography. Chordal rupture was seen more in the posterior leaflet than in the anterior leaflet. Movement of the anterior leaflet may be influenced by a prolapsed and hypermobile posterior leaflet and/or regurgitant jet flow caused by the posterior leaflet prolapse.