Pediatr Cardiol 5:217-220, 1984 Pediatric Cardiology 9 Springer-Verlag 1984 Complex Transposition with Interrupted Right Aortic Arch and Partial Di George Syndrome: Successful Palliation with Combined Medical and Surgical Therapy Walter J. Duncan, j Michael J. Tyrrell, ~ Baikunth Bharadwaj, 2 Alan M. Rosenberg, I Maria- Louise Schroeder, I and William T. Bingham ~ ~Department of Pediatrics and -'Department of Surgery, University Hospital, University of Saskatchewan, Saskatoon, Canada SUMMARY. A five-day-old infant with transposition of the great arteries, ventricular septal defect, and an interrupted right aortic arch underwent successful balloon septostomy, pulmonary artery banding, and aortic arch repair. The infant also had abnormal facies with severe refractory hypocaicemia and depressed T-lymphocyte number and function believed to represent a partial Di George syndrome. The hypocalcemia resolved following treatment with a vitamin-D analogue, T-cell number increased, and T-cell function improved, but both remained subnormal. KEY WORDS: Interrupted aortic arch m Di George syndrome Case Report A full-term female infant was seen at three days of age because of tachypnea, tachycardia, and cyanosis. Femoral pulses were reduced. Auscultation demonstrated a grade-3/6 pansystolic murmur with a single loud second sound. The chest roentgeno- gram showed enlargement of all cardiac chambers and increased vascularity. The electrocardiogram was normal for age. Two- dimensional echocardiographic examination showed transposi- tion of the great arteries with a subpulmonary ventricular septal defect, an atrial septal defect, and a small anterior aorta with a poorly defined transverse aortic arch. Cardiac catheterization confirmed the echocardiographic features and revealed a right aortic arch with the left and right carotid arteries arising as the first and second branches with interruption beyond the right subclavian artery (Fig. 1). A left descending aorta was perfused through the ductus arteriosus connection to the main pulmonary artery. The left subclavian artery arose from the superior aspect of the descending aortic segment. A balloon atrial septostomy was performed and prostaglandin E~ infusion commenced. Surgical repair of the aortic arch interruption was performed with the benefit of right radial and umbilical arterial pressure monitoring. The aorta was side clamped and a 6-mm polytetra- fluoroethylene graft was sutured from the proximal ascending aorta to the upper descending aorta. The pulmonary artery was banded to 40% of the diameter of the pulmonary valve annulus. Address reprint requests to: Walter J. Duncan, MD, Department of Pediatrics, University Hospital, Saskatoon, Saskatchewan, Canada S7N 0W0. Postoperatively, there was acute renal failure of unknown etiology which did not require dialysis. Transient seizures, believed to be due to a hypoxic-ischemic encephalopathy or hypocalcemia, responded to a brief course of phenobarbital therapy. There was persistent hypocalcemia despite vigorous replacement with 15% solutions of calcium gluconate. Serum phosphorus was elevated at 3.4 mmol/liter. Therapy with 1-25 dihydroxytachysterol was commenced, with prompt resolution of both the hypocalcemia and hyperphosphatemia. A serum Parathormone level done at a calcium level of 1.8 retool/liter was 2350 ng/liter (normal = 430-1860 ng/liter), consistent with reac- tive hyperparathyroidism. Immunologic studies, undertaken when the serum calcium was normal, revealed that only 14% of lymphocytes were T cells (normal 55%--75%) and no appreciable in vitro responses to the predominantly T-cell mitogenic stimu- lants phytohemagglutinin and concanavalin A were demonstrat- ed. By ten days of age, based on refractory hypocalcemia, hyperphosphatemia, deficient lymphoid tissue, and prompt im- provement with 1-25 dihydroxytachysterol, the presumptive diagnosis of Di George syndrome was made. The baby improved steadily, and by 18 days after surgery she was on full feedings in room air, and neither 1-25 dihydroxyta- chysterol nor calcium supplements were required to maintain normal serum levels of calcium and phosphorus. The renal failure resolved and the cardiac status stabilized. Postoperative catheterization showed an intact repair with mild stenosis at the proximal end of the surgical graft, producing a gradient of 9 mmHg (Fig. 2). The pulmonary band was effective (gradient 80 mmHg) and the aortic saturation satisfactory at 76%. A small right ductus arteriosus was connected to the right pulmonary artery.