Pulmonary atresia pathophysiology


 * 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
In a normal heart, the opening in the pulmonary valve has three flaps to open and close. In a patient with pulmonary atresia, the flap-like openings are covered by a layer of tissue. This significantly impacts the ability for the heart to shunt blood to the lungs for oxygenation.

Pathophysiology
The pulmonary valve is located on the right side of the heart between the right ventricle and pulmonary artery. In a normal functioning heart, the opening to the pulmonary valve has three flaps that open and close like one way doors. As these flaps open and close they force blood to flow forward into the pulmonary artery and backward into the right ventricle then forward again to the lungs where the blood becomes oxygenated. With the disease pulmonary atresia, the flap-like openings are completely covered by a layer of tissue, thus preventing the ability of blood flow to the lungs to become oxygenated. The body requires oxygenated blood for survival. Pulmonary atresia is not threatening to a developing fetus however, because the mother's placenta provides the needed oxygen since the baby's lungs are not yet functional. Once the baby is born its lungs must now provide the oxygen needed for survival, but with Pulmonary atresia there is no opening on the pulmonary valve for blood to get to the lungs and become oxygenated. Due to this, the newborn baby is blue in color and pulmonary atresia can usually be diagnosed within hours or minutes after birth.