Pulmonary Atresia With Intact Ventricular Septum

Excerpt

Pulmonary atresia with intact ventricular septum (PA-IVS) is one of the rare forms of congenital heart disease, accounting for <1% of total heart defects. PA-IVS is characterized by membranous or muscular atresia of the right ventricular outflow tract without any ventricular communication, often involving underdevelopment of the right ventricle and tricuspid valve (see Image. Pulmonary Atresia With Intact Ventricular Septum).

The anomaly was first described by Hunter in 1783 and later by Peacock in 1869. PA-IVS presents significant variability, influencing postoperative outcomes based on various factors, eg, the size of the right ventricle and tricuspid valve, as well as the presence of right ventricle-dependent coronary circulation (RVDCC). Genetic research highlights that heterotaxy and right ventricular outflow tract obstruction are highly heritable congenital heart disease forms, but the precise cause of PA-IVS remains unknown. Theories suggest that potential causes may include issues with pulmonary valve development, tricuspid valve flow restriction, or coronary artery anomalies.

Newborns with PA-IVS often exhibit cyanosis and desaturation, especially after the closure of the ductus arteriosus, which is crucial for their pulmonary circulation. Physical examination may reveal single first and second heart sounds, a pansystolic murmur if the tricuspid valve regurgitates, and possibly a murmur from a patent ductus arteriosus. The diagnosis of this anomaly is predominantly made through echocardiography, which can detect PA-IVS prenatally in about 86% of cases. This imaging assesses the interatrial septum, tricuspid valve, right ventricle, and branch pulmonary arteries.

However, echocardiography alone cannot determine coronary circulation details, necessitating cardiac catheterization with angiography to assess coronary connections and RVDCC fully. Managing PA-IVS begins with prostaglandin infusion to maintain ductal patency, which is crucial for survival preoperatively. Intervention, either catheter-based or surgical, is necessary for neonates. Treatment is highly individualized, encompassing biventricular repair, systemic-to-pulmonary shunts, single-ventricular repair, or heart transplantation, depending on the characteristics of the right ventricle and tricuspid valve, as well as the anatomy of the coronary arteries.