Congenitally corrected transposition of the great arteries: the systemic right ventricle

Apico-pulmonary artery conduit repair of congenitally corrected transposition of the great arteries with ventricular septal defect and pulmonary outflow tract obstruction: A 10-year follow-up

BACKGROUND

In conventional repair of the congenitally corrected transpositions of the great arteries associated with ventricular septal defect and pulmonary outflow tract obstruction, the placement of the left ventricle-pulmonary artery conduit is at risk owing to probable compression by the sternum, heart block, or injury to the mitral anterior papillary muscle. Apical placement of the left ventriculotomy for the inflow conduit rather than in the midportion or base placement may avoid these complications, although this results in a long and winding extracardiac conduit that may be short-lived because of the proliferation of pseudointima.

METHODS

Between 1985 and 1990, a nonvalved Dacron woven-fabric graft conduit was placed between the left ventricular apex and pulmonary artery in 5 patients (mean age, 6.2 +/- 1.7 years) who were then followed for at least 10 years.

RESULTS

No iatrogenic heart blocks or mitral regurgitation developed. All patients were complaint-free during the follow-up period, although 1 patient who was clinically well died suddenly in the 10th follow-up year. Cardiac catheterization in the 10th follow-up year indicated a pressure gradient of 21 +/- 6 mm Hg across the conduit, and angiography revealed that the conduit diameter was 91% +/- 6% of the original conduit diameter.

CONCLUSIONS

The reportedly poor early and late outcomes that occur after a conventional repair of congenitally corrected transpositions of the great arteries associated with ventricular septal defect and pulmonary outflow tract obstruction, which places an extracardiac conduit between the left ventricle and the pulmonary artery, may be partially neutralized by relocating the inflow position to the apex.

Congenitally Corrected Transposition of the Great Arteries: Current Treatment Options

Congenitally corrected transposition of the great arteries is a relatively rare cardiac malformation characterized by atrioventricular and ventriculoarterial discordance. This double discordance results in a physiologically corrected circulation with the morphologic right ventricle (RV) serving as the systemic pump. Associated anomalies are present in approximately 98% of cases and include most commonly ventricular septal defect, pulmonary stenosis, and anomalies of the systemic atrioventricular valve (SAVV). Conduction abnormalities are common as well, predisposing these patients to the development of complete heart block. The management of these patients is primarily determined by the presence and severity of the associated anomalies. Conventional repair, which leaves the morphologic RV as the systemic ventricle, has resulted in high incidence of tricuspid regurgitation (TR) and progressive dysfunction of the RV. In the majority of patients, congestive heart failure secondary to RV dysfunction occurs by the fifth or sixth decade. The cause and effect relationship between TR and RV dysfunction remains to be determined. The advent of the Double Switch operation, which restores the morphologic left ventricle (LV) as the systemic ventricle, has yielded favorable outcomes at early follow-up. This procedure should be applied in young patients to achieve optimal results. Retraining the LV by pulmonary artery banding is associated with high morbidity and mortality when attempted after infancy or early childhood. Long-term follow-up is needed to evaluate the potential superiority of this procedure and the incidence of rhythm, baffle, and conduit complications for this management option.