Tetralogy of Fallot with pulmonary atresia is one of the most challenging congenital cardiac malformations, for the morphologist, cardiologist and surgeon alike. Much of the difficulty in this lesion concerns the nature and development of pulmonary arterial supply, and the manner in which complete segmental supply to the lungs can be successfully restored or maintained. In this review, we discuss the anatomy and nomenclature of the lesion, emphasising the variability that can occur in pulmonary arterial anatomy, particularly in the presence of systemic-to-pulmonary collateral arteries. We speculate on the likely embryologic origins of these connections. Then by means of anatomic-clinical correlations, we emphasise the diagnostic approach to delineating the origin and extent of the pulmonary vasculature.

The arterial supply to the lungs in cases with tetralogy of Fallot with pulmonary atresia or critical pulmonary stenosis is mostly via the arterial duct or else by collateral arteries arising directly or indirectly from the aorta. Nine anatomical specimens with collateral arteries were studied by blunt dissection to determine the arterial supply to each pulmonary segment. The precise supply varied from case to case but, overall, nearly two-thirds of the pulmonary segments were connected to the central pulmonary arteries. A quarter were supplied exclusively by systemic-to-pulmonary collateral arteries, with the remainder having a dual supply. Coexistence of ductal connections and systemic-to-pulmonary collateral arteries was seen in one case. Anastomoses between vessels of different origins were observed up to the segmental level in eight of the nine cases. In four cases, the anastomoses formed arterial rings. The extent of pulmonary parenchyma supplied by arteries from different sources and the presence of arterial anastomoses in these malformations have implications on the planning of surgical repair.