Comment
Anomalous origin of branch pulmonary artery from aorta (AOPA) is an extremely rare condition accounting for only 0.1% of all congenital heart defects. (1) Aortopulmonary septum develops by fusion of right and left conotruncal ridges. Severe mal-alignment of these conotruncal ridges results in anomalous origin of the RPA from the ascending aorta. AOPA can be isolated or it may be associated with other cardiac defects. The most common associated lesion is patent ductus arteriosus, seen in 50% of cases. Rarely, it is associated with TOF, ventricular septal defect (VSD), Aortopulmonary window ( APW), Interrupted aortic arch and atrial septal defect. Anomalous origin of right pulmonary artery (AORPA) is far more common than anomalous origin of left pulmonary artery (AOLPA). (2) However, in tetralogy of Fallot AOLPA is far more common than AORPA. Clinical features are those of increased pulmonary blood flow and congestive heart failure. The cyanosis associated with tetralogy of Fallot may not be apparent due to increased blood flow to the ipsilateral lung. Differential lung vascularity on chest radiogram may be suggestive of the diagnosis. The repair should be performed immediately after diagnosis to prevent congestive heart failure and ipsilateral pulmonary hypertension. Our patient had an added complexity in the form of anomalous coronary crossing the pulmonary annulus. The incidence of anomalous coronary artery or a large conal artery crossing the RVOT is 10.2% based on a meta analysis of 28 studies. (3) The combination of AOPA and ACA with TOF has not been previously reported in the literature. ACA was circumvented by interposing a hand-sewn bovine pericardial tube with a tri-leaflet valve constructed from PTFE membrane. The integrity of the native pulmonary valve was maintained allowing future growth as has been proposed in literature. (4) This was demonstrated in our patient on echocardiogram examination. The native pulmonary annulus has increased in diameter from 6 mm to 8 mm over a period of 30 months. A promise of this growth potential combined with a larger than required RV to PA conduit will delay or perhaps prevent re-operations for the RVOT.