Chris Wilkenson, MD
Overview and Natural History
Pulmonary atresia with intact ventricular septum (PA/IVS) is characterized by atresia of the pulmonary valve. The pulmonary valve is imperforate by way of a membranous or thicker muscular atresia. The ventricular septum is intact and pulmonary blood flow is dependent on a patent ductus arteriosus. PA/IVS is a disease with significant heterogeneity based on multiple anatomic factors including the degree and form of pulmonary atresia, the size of the right ventricle and tricuspid valve (both of which often demonstrate significant degrees of hypoplasia). In addition, the coronary circulation is often abnormal with an association between the RV and subepicardial coronary arteries or more typically called “RV dependent coronaries.” This lesion will typically present in the neonatal period and depending on multiple factors, can be managed with a biventricular repair, single ventricle palliation or, one and a half ventricle pathway or cardiac transplantation (usually reserved for the most severe variants with severe coronary disease and ventricular dysfunction).
Epidemiology
PA/IVS is found in about 6 to 8.3 in 100,000 live births. This number is thought to be an underestimation due to the frequency of fetal or in utero termination.
Genetics
There is no sex predilection or identifiable genetic cause known at this time.
Types
PA/IVS is a complex lesion with heterogeneity in procedural pathways, prognosis, as well as anatomic variance. The important characteristics in PA/IVS:
Additional important features and characteristics:
Hemodynamics
The hemodynamics can differ greatly depending on the specific constellation of anatomic variance. There will be progressive cyanosis in the early neonatal period. They will typically be a murmur related to the degree of tricuspid valve regurgitation as well as a ductal murmur. These patients will need prostaglandin infusion in the neonatal period to ensure patency of the patent ductus arteriosus in order to maintain adequate pulmonary blood flow.
Goals of Echocardiography Exam
It is recommended to use high-frequency probes and small sector width to optimize high spatial and temporal resolution. Generally, 3-5 beat clips are preferred and still frames should be avoided.