What is Pulmonary Atresia?
Pulmonary atresia (PA) is a complicated congenital (present at birth) defect that occurs when the pulmonary valve, located between the right ventricle and pulmonary artery, is not formed properly. The pulmonary valve has three leaflets that function like a one-way door, allowing blood to flow forward into the pulmonary artery, but not backward into the right ventricle. With pulmonary atresia, problems with valve development prevent the leaflets from opening; therefore, blood cannot flow forward from the right ventricle to the lungs. Before birth, while the fetus is developing, this is not a threat to life, because the placenta provides oxygen for the baby, and the lungs are not functional. Blood entering the right side of the fetal heart passes through an opening called the foramen ovale, which allows oxygen-rich (red) blood to pass through to the left side of the heart and proceed to the body.
Pulmonary atresia (PA) is a complicated congenital (present at birth) defect that occurs due to abnormal development of the fetal heart during the first 8 weeks of pregnancy. The pulmonary valve is found between the right ventricle and the pulmonary artery. It has three leaflets that function like a one-way door, allowing blood to flow forward into the pulmonary artery, but not backward into the right ventricle.
Pulmonary atresia is a congenital heart defect in which the pulmonary valve fails to form properly and completely blocks the passage of blood to the lungs. The pulmonary valve’s primary function is to deliver blood back to the lungs to pick up oxygen. When the valve is so malformed as to not provide any pathway to the smaller pulmonary arteries, heart failure is imminent if not surgically addressed. Often, pulmonary atresia is accompanied by other defects. A variant of Tetralogy of Fallot often occurs with pulmonary atresia. In other cases, the formation of the pulmonary valve and the right ventricle are both affected. This serious, though rare set of defects, called hypoplastic right heart syndrome, cannot be corrected, but is addressed either through the staged surgeries of the Fontan or through transplantation. Whether alone or accompanied by other defects, pulmonary atresia must be treated during the first few days of a child’s life. Diagnosis, if not made prenatally, is usually ma
When the heart squeezes, the right ventricle (the lower right chamber) contracts, pushing the blood out to the lungs. The pulmonary valve sits on the way out of the heart to the lungs, to prevent blood from leaking back into the heart between beats. In pulmonary atresia, the pulmonary valve has not formed correctly and cannot open. Many children with pulmonary atresia also have a ventricular septal defect, a hole in the tissue between the lower chambers of the heart. This combination is often called tetralogy of Fallot with pulmonary atresia.
