Pulmonary atresia with intact ventricular septum (i.e. without a ventricular septal defect), occurs when the pulmonary valve fails to form normally while the baby is in the mother's womb. It is quite rare comprising about 3% of all congenital heart defects.
The pulmonary valve is one of four valves in the normal heart. It sits between the right ventricle (1) and the pulmonary artery (2). In babies with pulmonary atresia, the pulmonary valve (3) is so small that blood flow leaving the right heart is completely blocked. Almost all babies with this defect also have an atrial septal defect (4) that allows blue blood to bypass the obstruction, flowing from the right atrium to the left atrium, the left ventricle and out to the body. The only way that blood can reach the lungs is to flow backwards from the aorta through a patent ductus arteriosus (5). This a small blood vessel that, prior to birth, permits the blood to by-pass the baby's fluid-filled lungs. In most babies, one or two days after birth, this vessel closes. In a baby with pulmonary atresia, if the duct closes, blood can no longer reach the lungs. Therefore, after the diagnosis is made, a medicine called prostaglandin is used to keep the ductus arteriosus from closing before surgery.
In most babies with pulmonary atresia, the right ventricle and the tricuspid valve (6) are also too small, although the degree that these structures are affected varies. In about 50% of the babies, there are direct connections between the right ventricle and the coronary arteries called fistulae. The coronary arteries are the blood vessels that supply the heart itself with red or oxygenated blood. If present, coronary artery fistulae can make surgical repair more difficult.
Like most heart defects, pulmonary atresia does not have an adverse effect until after the baby is born. Most children develop heart-related symptoms within the first 3 or 4 days of life. Since blood flow to the lungs is decreased, the major problem is low blood oxygen. This causes a bluish color of the lips and fingernails. The medical term for this blue color is cyanosis.
Pulmonary atresia/intact ventricular septum is a serious problem requiring heart surgery soon after birth. The surgical plan is based on the size of the tricuspid valve and the right ventricle. If these structures are good-sized or if the sizes are at least borderline, the surgical goal will be a two-ventricle repair. If these structures are clearly too small to ever provide adequate blood flow to the lungs, then single ventricle repair will be needed.
Prenatal diagnosis: Pulmonary atresia can be diagnosed before birth by a fetal echocardiogram or heart ultrasound as early as 18 weeks into the pregnancy. This test is done when there is a family history of congenital heart disease or when a question is raised during a routine prenatal ultrasound.
Symptoms: In a newborn baby, usually, cyanosis is what alerts parents or health care providers that the child may have a heart problem. This is most often noted during the first 3 or four days of life.
Physical findings: Most babies with pulmonary atresia are born at term and are a normal weight and length (since before birth the baby's oxygen comes from the mother). After birth, the baby's lips and fingernails may look blue. A heart murmur is almost always heard.
Medical tests: The suspected diagnosis is confirmed by an echocardiogram. Sometimes, a heart catheterization may is needed to help the doctors plan the surgery. An oxygen saturation test is used to measure the blood oxygen levels. Other tests include an electrocardiogram and chest x-ray. back to top
Prostaglandin is started as soon as possible after the diagnosis is made to ensure a safe blood supply to the lower body. Surgery is needed soon after birth but the specific operation needed depends on the size of the right ventricle and the tricuspid valve. In some babies, if these are large enough, the area of the pulmonary valve can be cut and widened with a patch (1). At some point in the future, another surgery to replace the pulmonary valve may be needed. If there is concern that the sizes of the right ventricle and/or the tricuspid valve are borderline, an aorto-pulmonary shunt (2) will be placed. This operation involves sewing a Gortex tube between the subclavian artery (3) and the right pulmonary artery (4). Through this tube, a fixed amount of blood reaches the lungs with each heartbeat.
If the tricuspid valve and or right ventricle are clearly too small to pump blood to the lungs, the child will undergo a three-staged surgical repair. Please click here to learn more about these operations.
After the operations, most children live quite normal lives and most have normal intelligence. They are able to go to daycare, school, play with friends, and participate in the usual recreational activities. Children who undergo the three-staged surgical repair tend to have lower endurance levels than others their age and may require more rests during physical activities. These children are usually restricted from participation in vigorous and competitive sports so it is important for parents to help them find other areas of interest.
SBE prophylaxis: Children with pulmonary atresia are at increased risk for subacute bacterial endocarditis (SBE). This is an infection of the heart caused by bacteria in the blood stream. Children with heart defects are more prone to this problem because of the altered flow of blood through the heart and or abnormalities of the valves. It can occur after dental work or medical procedures on the GI or respiratory tract because these procedures almost always result in some bacteria entering the blood. SBE can usually be prevented by taking an antibiotic before these procedures.
Exercise guidelines: An individual exercise program is best planned with the doctor so that all factors can be included. Children with pulmonary atresia are usually restricted from vigorous or competitive sports but can participate in recreational sports. It is important for them to always be able to self-limit their activity, that is, to rest whenever they feel the need to do so. The children can usually participate in gym class but should be allowed to self-limit their level of exertion and they should not be graded (which could increase the pressure to exceed their natural limits).
Freedom RM & Nykanen D. Pulmonary atresia and intact ventricular septum. In Allen H, Gutgesell HP, Clark EB & Driscoll D, eds. Moss and Adams' heart disease in infants, children and adolescents, Vol 2, 2001:845-860.
Yuh D & Reitz B. Obstructive lesions. In Reitz B & Yuh D, ed. Congenital Cardiac Surgery, 2002. New York: McGraw Hill, 97-100.
Written by: S. LeRoy RN, MSN, CPNP
Reviewed January, 2010