There were 223 patients who underwent ASO at a median age of 6 days and median weight of 3.5 kg. Patient characteristics are summarized in (Table le1). Of the 97 patients with VSDs (44% of the study population), 12 (12%) had multiple VSDs and six (6%) had conoventricular malalignment-type defects. Twenty-six patients (12%) had aortic arch obstruction requiring surgery; 13 underwent aortic arch repair before ASO, 11 patients had arch repair at the time of ASO and 2 had coarctation repair within the first year after ASO. Eight patients (4%) had right ventricular hypoplasia, according to the defined criteria. The position of the great arteries (aorta in relation to the PA) was anterior and rightward in 57% of patients, anterior/posterior in 15%, side-by-side in 8% and anterior and leftward in 5%, and in 1% of the patients, the aortic valve was posterior and rightward relative to the pulmonary valve. Other associated lesions included abnormal pulmonary valve morphology (n = 11), juxtaposed atrial appendages (n = 5), abnormal tricuspid valve attachments (n = 4), cleft mitral valve (n = 2), aberrant origin of the right subclavian artery (n = 2), straddling mitral valve (n = 1), right aortic arch (n = 1), primum-type atrial septal defect (n = 1), bicuspid aortic valve (n = 1), dextrocardia (n = 1) and situs inversus (n = 1). There were 12 patients (5%) in this series with Taussig-Bing anomaly, defined as a double outlet right ventricle with a subpulmonary ventricular septal defect, mitral-to-pulmonary valve fibrous discontinuity and side-by-side great vessels (24). Patients with Taussig-Bing anomaly differed from the d-TGA group in that they were significantly older at the time of surgery (median age at surgery for d-TGA 6 days, and for Taussig-Bing 70 days, p < 0.002). Repair beyond three months of age was performed in 17 patients (8%), 6 (35%) of whom underwent two-stage repair (25- 26) with a PA band placement before ASO. Most patients (n = 194, 87%) underwent preoperative balloon atrial septostomy, either in the ICU under echocardiographic guidance or in the cardiac catheterization laboratory. The distribution of coronary anatomy pattern and the associated mortality in each type are shown in (Figure 1). This distribution is comparable to the coronary distribution of the previous cohort (12). Of the 4 patients with intramural coronary anatomy, 2 had intramural left coronary arteries, 1 had an intramural right coronary and 1 had an intramural left anterior descending artery. The prior operations performed are summarized in (Table le2).