Pulmonary atresia with intact ventricular septum (PA/IVS) is characterized by complete obstruction to right ventricular outflow with varying degrees of right ventricular and tricuspid valve hypoplasia. Blood is thus unable to flow from the right ventricle to the pulmonary artery and lungs, and an alternative source of pulmonary blood flow is required for survival. If untreated, PA/IVS is a uniformly fatal form of structural cardiac disease. Outcomes of surgical interventions are improving with a five-year survival rate of approximately 80 percent.
The definition, anatomy, physiology, clinical presentation, management, including follow-up care, and outcome of PA/IVS will be reviewed here.
PA/IVS is a rare congenital cardiac defect that consists of atresia of the pulmonary valve resulting in an absent connection between the right ventricular outflow tract (RVOT) and pulmonary arteries, and an intact ventricular septum that allows no connection between the right and left ventricles.
PA/IVS is distinctive from pulmonary atresia with a ventricular septal defect (PA/VSD), and from severe forms of Ebstein’s anomaly of the tricuspid valve. Although all of these defects can result in complete obstruction of RVOT blood flow, they have different morphologic anatomic features (eg, right ventricular size and function, presence of pulmonary and/or tricuspid valve abnormalities, and status of the ventricular septum), which have an impact on management decisions.
●PA/IVS features developmental abnormalities of the right ventricle and tricuspid valve that are “upstream” of the pulmonary outflow. The pulmonary arteries are small, but their architecture and branching are otherwise normal.