Transposition Of The Great-Arteries With Displaced Atrioventricular Valves Or Chordae - Echocardiographic Appearances And Surgical Correlations

The authors report the echocardiographic appearances of 27 cases of transposition of the great arteries (TGA) with ventricular septal defect (VSD) (including the Taussig-Bing malformation) complicated by displacement of one or both atrioventricular valves and/or chordae tendinae diagnosed between September 1985 and September 1994. An anatomical repair was performed in 21 cases and allowed accurate correlation of the echocardiographic and peroperative findings; a cavo-bipulmonary conduit or a palliative procedure was performed in 6 cases. The cases were classified in 3 groups: group I: 16 children with isolated tricuspid valve abnormalities; group II: 7 cases of mitral valve straddling; group III: 4 cases of displacement of both atrioventricuspid valves and/or their chordae. The cases of group I were divided into 3 subgroups: subgroup Ia with insertion of the tricuspid chordae on the infundibular septum (7 cases); subgroup Ib with isolated overriding of the tricuspid valve (2 cases); subgroup Ic straddling with or without overriding of the tricuspid valve (7 cases). In all three groups, there were 10 cases of straddling of the tricuspid and 11 cases of straddling of the mitral valve: 9 type A, 3 type B and 9 type C of Tabry's classification. Echocardiography misdiagnosed one case of type A straddling of the tricuspid valve for a type A overriding and straddling of the mitral valve. The ventricular septal defect was situated in the admission septum in the 10 cases of straddling of the tricuspid; in the 11 cases of straddling of the mitral valve the chordae passed through the superior anterior part of the interventricular septum. Two cases of straddling with overriding of the mitral valve were associated with left ventricular hypoplasia. The anatomical repair could not be performed in three cases because of straddling of an atrioventricular valve; two type C straddling of the tricuspid valve and one case of straddling of both atrioventricular valves. The recognition of straddling of an atrioventricular valve by echocardiography modified the surgical strategy in 5 cases and led to palliative procedures. The results of this series show that the presence of a type C straddling or the presence of a double straddling and ventricular hypoplasia are poor prognostic factors for anatomical repair of TGA with VSD.