Successful repair of an atrial septal defect associated with right to left shunting.

An atrial septal defect was successfully repaired in a young woman despite the presence of pulmonary hypertension and right to left shunting. Before repair both isoprenaline infusion and 100% inspired oxygen produced significant falls in pulmonary artery pressure and pulmonary vascular resistance. A lung biopsy specimen at operation indicated a considerable decrease in the concentration of parenchymal pulmonary arteries and an absence of intimal fibrosis or medial hypertrophy. Pulmonary artery banding performed in infancy, as part of the management of a ventricular septal defect, may have contributed to the underdevelopment of the pulmonary vascular tree. The reduced number of pulmonary arteries is a possible explanation for the pulmonary hypertension.