Absent pulmonary valve is a rare defect in which the pulmonary valve is either missing or poorly formed. Oxygen-poor blood flows through this valve from the heart to the lungs, where it picks up fresh oxygen. This condition is present at birth (congenital).
Absent pulmonary valve occurs when the pulmonary valve does not form or develop properly while the baby is in the mother's womb. When present, it often occurs as part of a heart condition called tetralogy of Fallot. It is found in about 3% to 6% of people who have tetralogy of Fallot.
When the pulmonary valve is missing or does not work well, blood does not flow efficiently to the lungs to get enough oxygen.
In most cases, there is also a hole between the left and right ventricles of the heart (ventricular septal defect). This defect will also lead to low-oxygen blood being pumped out to the body.
The skin will have a blue appearance (cyanosis), because the body's blood contains a low amount of oxygen.
Absent pulmonary valve also results in very enlarged (dilated) branch pulmonary arteries (the arteries that carry blood to the lungs to pick up oxygen). They can become so enlarged that they press on the tubes that bring the oxygen into the lungs (bronchi). This causes breathing problems.
Other heart defects that can occur with absent pulmonary valve include:
Heart problems that occur with absent pulmonary valve may be due to defects in certain genes.
Symptoms can vary depending on which other defects the infant has, but may include:
Absent pulmonary valve may be diagnosed before the baby is born with a test that uses sound waves to create an image of the heart (echocardiogram).
During an exam, the health care provider may hear a murmur in the infant's chest.
Tests for absent pulmonary valve include:
Infants who have breathing symptoms typically need surgery right away. Infants without severe symptoms most often have surgery within the first 3 to 6 months of life.
Depending on the type of other heart defects the infant has, surgery may involve:
Types of surgery for absent pulmonary valve include:
Infants with severe breathing symptoms may need to get oxygen or be placed on a breathing machine (ventilator) before and after surgery.
Without surgery, most infants who have severe lung complications will die.
In many cases, surgery can treat the condition and relieve symptoms. Outcomes are most often very good.
Complications may include:
Call your provider if your infant has symptoms of absent pulmonary valve. If you have a family history of heart defects, talk to your provider before or during pregnancy.
Although there is no way to prevent this condition, families may be evaluated to determine their risk for congenital defects.
Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.