Pulmonary atresia classification with intact ventricular septum


 * Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [mailto:psingh@perfuse.org], ; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [mailto:kfeeney@perfuse.org]

Overview
Pulmonary atresia with intact ventricular septum is a rare congenital lesion associated with a complete blockage of the pulmonary vale. Pulmonary atresia with intact ventricular septum can be further classified into type I or type II depending largely on the complexity of the cardiac lesion as characterized by one of two patterns of pathophysiology.

Pulmonary atresia with intact ventricular septum (PA-IVS)
PA-IVS is a rare congenital lesion. This lesion can be diagnosed during the fetal stage of life by using fetal echocardiography, which is a test that uses sound waves to look at the structure of an unborn baby's heart. PA-IVS involves complete blockage of the pulmonary valve located on the right side of the heart. This blockage thus prevents the flow of blood to the lungs. Because of this lack of blood flowing through the right side of the heart, the structures on that side, such as the pulmonary valve and the tricuspid valve, are abnormally small. The genetic cause of PA-IVS is unknown. It is rare, occurring in around 7.1-8.1 per every 100,000 live births.

With intact ventricular septum: complex cardiac lesion characterized by one of two patterns of pathophysiology.

Type I disease
In this particular type, there is a combination of pulmonary valvular atresia, competent tricuspid valve, and an intact ventricular septum. As a consequence a right ven­tri­cular hypertrophy and chamber obliteration with supra­systemic pressures is developed, which force blood through the myocardial sinusoids that feed the right ventricle into the coronary circulation.

Type II disease
This type consist of proximal pulmonary arterial atresia, an intact ventricular septum, but the tricuspid valve is incompetence allowing retrograde flow of blood into the right atrium and across an atrial septal defect. TTherefore, the right ventricle is either normal or dilated.

Survival has improved due to a combination of the early treatment with Prostaglandin PGE1 (to prevent the PDA from closing) and advances in cardiac surgery (creating shunts between the aorta and the pulmonary artery that may help increase blood flow to the lungs). A more complete repair will depends on the size of the pulmonary artery and right ventricle.