Pulmonary atresia with VSD
It is an extremely form of tetralogy of Fallot; the pulmonary valve is atretic and the pulmonary trunk is hypoplastic or atretic (fig 6.3). This represents an neonatal emergency because the pulmonary blood flow depend on ductus arteriosus.
A medical and surgical treatment is immediately required. Once recognized a medical therapy is started with prostaglandin E1 given intravenously in order to maintain the ductus arteriosus open. Other laboratory investigations can be performed and the surgery programmed. The first operation is the Blalock - Taussig intervention (fig. 6.2) to create a safe communication between systemic and pulmonary circulation and obtain a good growth of the pulmonary artery size which is the crucial point for the radical surgery which consist in establishing a connection between right ventricle and pulmonary artery with a conduit.
Sometimes pulmonary atresia with VSD is not ductus dependent for pulmonary circulation which is sustained by arteries called collateral systemic-pulmonary arteries coming from aorta. This feature is less dramatic and not life threatening in neonatal period.