Anomalous origin of the left pulmonary artery from the ascending aorta in two children with pulmonary atresia, sub-aortic ventricular septal defect and right-sided major aorto-pulmonary collateral arteries L PEPETA, FF TAKAWIRA, PE ADAMS, NH NTSINJANA, BJ MITCHELL, AM CILLIERS
AbstractWe report two rare cases of an anomalous origin of the left pulmonary artery (AOLPA) from the ascending aorta, associated with pulmonary atresia, a ventricular septal defect and a left aortic arch. The cases are unusual because AOLPA is more commonly associated with a right aortic arch and it is more usual for the right pulmonary artery to originate anomalously from the ascending aorta. The pulmonary blood supply to the right lung in both patients was absent and provided instead by major aorto-pulmonary collateral arteries which were stenosed at multiple levels. The AOLPA in both patients originated from the postero-lateral aspect of the ascending aorta just distal to the sino-tubular junction. Only one patient showed the more common association of an unusual aortic arch branching pattern in the form of an anomalous right subclavian artery.Neither patient was in heart failure and the chest X-ray in both revealed differential pulmonary perfusion with prominent vascularity of the left lung. Cardiac catheterisation showed systemic pressures within the anomalous left pulmonary artery. Karyotyping revealed normal chromosomes, and fluorescent in-situ hybridisation done in one patient was negative for chromosome 22q11.2 microdeletion. Both patients have been managed conservatively.Keywords: pulmonary atresia with ventricular septal defect, anomalous origin of pulmonary artery, collateral arteries, pulmonary hypertension, branchial arches, CATCH22 syndrome An anomalous origin of the pulmonary artery from the aorta (AOPA) is very rare, with the first case of this nature reported by Fraentzel in 1868. 1 The incidence of anomalous left pulmonary artery from the aorta (AOLPA) was reported in one study to be around 17%, 1 with anomalous origin of the right pulmonary artery (AORPA) from the ascending aorta as the more common variant of AOPA, seen in about 83% of cases. Without surgery, the mortality in patients with AOPA is extremely high, reaching as high as 80%. [2][3][4][5] This is due to severe, rapidly progressive pulmonary vascular disease and congestive cardiac failure. Both isolated AOLPA and that associated with other defects have been well described. 1,6,7 The commonest associated congenital cardiac lesion is tetralogy of Fallot, which is seen in about 75% of cases. 1 AOLPA is also associated with a right arch of the aorta in 63% of cases, and in about 38% of cases, an anomalous origin of the right subclavian artery from the descending aorta has been reported as well. 1 Of note, both our cases had a left aortic arch and had no main and right pulmonary arteries, with the only source of blood supply to the right lung being partially stenosed major aorto-pulmonary collateral arteries (MAPCAs).To the best of our knowledge, this series repr...
