Functional acquired pulmonary atresia secondary to subpulmonary aneurysmal tissue: a rare form of pulmonary outflow tract obstruction

Abstract

artery (PA) arising from rudimentary pouch (*). Fetal echocardiography was performed at 19 and 29 weeks gestation after an abnormal screening ultrasound suggested left heart hypoplasia. The echocardiogram revealed left-sided hypoplasia with d-transposition of the great arteries and a small, posteriorly positioned pulmonary artery (PA) with both prograde and retrograde flow demonstrated. There appeared to be a moderate ventricular septal defect and, of note, there was unusual aneurysmal tissue of indeterminate origin below the pulmonary annulus. Postnatal echocardiography confirmed d-transposition of the great arteries with the aorta anterior and rightward of the smaller PA. The PA arose directly from a rudimentary, aneurysmal blind pouch (Figure 1) with bidirectional flow between the blind pouch and the main PA (Figure 2). However, no communication between the pouch and the remainder of the heart could be demonstrated by Doppler interrogation. The aneurysmal pouch was centrally located in the heart and appeared to possibly consist of redundant atrioventricular (AV) valve tissue contiguous with a leaflet of the left-sided AV valve. The PA was supplied by a large, tortuous patent ductus arteriosus typical for pulmonary atresia. There were 2 distinct AV valves entering a common single ventricle, with hypoplasia of the left-sided AV valve noted. The patient was initially treated with prostaglandin infusion to maintain ductal patency, followed by placement of a right-sided Blalock-Taussig shunt in the neonatal period. She subsequently underwent successful bidirectional Glenn anastomosis and left pulmonary arterioplasty at 7 months of age. This case represents an extremely unusual form of functional pulmonary atresia in which abnormal intracardiac aneurysmal tissue of indeterminate ori-