Transposition complexes with systemic obstruction

The arterial switch operation is currently the procedure of choice for transposition of the great arteries and double-outlet right ventricle with subpulmonary ventricular septal defect. While the results of surgical repair have improved tremendously in recent years, the presence of associated lesions continues to make this a surgically challenging malformation. The association of these so-called transposition complexes with systemic obstruction has recently received increased attention. Systemic obstruction may occur at the subaortic level, in the aortic arch, or at both levels. Valvar aortic stenosis or atresia is extremely rare. Resection of hypertrophied muscle bundles with or without pericardial patch augmentation is frequently enough to deal with obstruction at the subaortic level, which becomes the subpulmonary area following arterial switch operation. Aortic arch obstruction associated with intracardiac defects has traditionally been addressed with a staged approach, dealing first with the arch obstruction followed later by intracardiac repair. The results with this approach have been disappointing. At the Montréal Children's Hospital, we have obtained superior results using a single-stage approach. Therefore, we have advocated the use of pulmonary homograft patch aortoplasty for aortic arch reconstruction at the time of intracardiac repair to completely remove any anatomic afterload. Since 1989, in 22 consecutive patients undergoing single-stage anatomic repair of transposition complexes associated with aortic arch obstruction, we have had no early deaths, one late death of a noncardiac cause, and one recoarctation requiring balloon dilatation. In the last 2 years, we have been able to perform all our aortic arch reconstructions avoiding the use of circulatory arrest.