Pulmonary atresia is a

congenital A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...

malformation of the

pulmonary valve The pulmonary valve (sometimes referred to as the pulmonic valve) is a valve of the heart that lies between the right ventricle and the pulmonary artery and has three cusps. It is one of the four valves of the heart and one of the two semilunar va ...

in which the valve orifice fails to develop. The valve is completely closed thereby obstructing the outflow of blood from the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...

to the

lungs The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of th ...

. The pulmonary valve is located on the right side of the heart between the

right ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper ...

and

pulmonary artery A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and t ...

. In a normal functioning heart, the opening to the pulmonary valve has three flaps that open and close In

congenital heart defects A congenital heart defect (CHD), also known as a congenital heart anomaly and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular ...

such as pulmonary atresia, structural abnormalities can include the valves of the heart, and the walls and

arteries An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pul ...

veins Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

near the heart muscle. Consequently, blood flow due to the aforementioned structural abnormalities is affected, either by blocking or altering the flow of blood through the human cardiac muscle.

Signs and symptoms

The symptoms/signs of pulmonary atresia that will occur in babies are consistent with

cyanosis Cyanosis is the change of body tissue color to a bluish-purple hue as a result of having decreased amounts of oxygen bound to the hemoglobin in the red blood cells of the capillary bed. Body tissues that show cyanosis are usually in locations ...

, some

fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

and some shortness of breath (eating may be a problem as well). In the case of

pulmonary atresia with ventricular septal defect Pulmonary atresia with ventricular septal defect is a rare birth defect characterized by pulmonary valve atresia occurring alongside a defect on the right ventricular outflow tract. It is a type of congenital heart disease/defect, and one of t ...

, decreased pulmonary blood flow may cause associated defects such as: *

Tricuspid atresia Tricuspid atresia is a form of congenital heart disease whereby there is a complete absence of the tricuspid valve. Therefore, there is an absence of right atrioventricular connection. This leads to a hypoplastic (undersized) or absent right ventri ...

Tetralogy of Fallot Tetralogy of Fallot (TOF), formerly known as Steno-Fallot tetralogy, is a congenital heart defect characterized by four specific cardiac defects. Classically, the four defects are: *pulmonary stenosis, which is narrowing of the exit from the ri ...

* RV w/ double-outlet

Cause

In terms of the cause of pulmonary atresia, there is uncertainty as to what instigates this congenital heart defect. Potential risk factors that can cause this congenital heart defect are those the pregnant mother may come in contact with, such as: * Certain

medications A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and rel ...

Diet Diet may refer to: Food * Diet (nutrition), the sum of the food consumed by an organism or group * Dieting, the deliberate selection of food to control body weight or nutrient intake ** Diet food, foods that aid in creating a diet for weight loss ...

Smoking Smoking is a practice in which a substance is burned and the resulting smoke is typically breathed in to be tasted and absorbed into the bloodstream. Most commonly, the substance used is the dried leaves of the tobacco plant, which have bee ...

Diagnosis

In regards to the diagnosis of pulmonary atresia 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

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. The diagnosis of pulmonary atresia can be done via the following exams/methods: an

echocardiogram An echocardiography, echocardiogram, cardiac echo or simply an echo, is an ultrasound of the heart. It is a type of medical imaging of the heart, using standard ultrasound or Doppler ultrasound. Echocardiography has become routinely used in th ...

, chest

x-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

EKG Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the hear ...

and an exam to measure the amount of in the body.

Classification

There are two types of pulmonary atresia. * Pulmonary atresia with intact ventricular septum (PA-IVS) is a rare

malformation. PA-IVS involves complete blockage of the

located on the right side of the heart. This blockage 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

and the

tricuspid valve The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, at the superior portion of the right ventricle. The function of the valve is to allow blood to flow from the right atrium to the right vent ...

, are abnormally small. *

Pulmonary atresia with ventricular septal defect Pulmonary atresia with ventricular septal defect is a rare birth defect characterized by pulmonary valve atresia occurring alongside a defect on the right ventricular outflow tract. It is a type of congenital heart disease/defect, and one of t ...

(PA-VSD) is identified by underdevelopment of the right ventricle. The Ventricular Septal Defect (VSD) is a second opening in the ventricular wall, which provides a way out for blood in the

. When this second opening does not exist, very little blood goes to the right ventricle, which is what causes it to be underdeveloped in PA-IVS, this defect can be determined before birth.

Treatment

The treatment of pulmonary atresia consists of: an IV medication called

prostaglandin The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are derive ...

E1, which is used for treatment of pulmonary atresia, as it stops the

ductus arteriosus The ''ductus arteriosus'', also called the ''ductus Botalli'', named after the Italian physiologist Leonardo Botallo, is a blood vessel in the developing fetus connecting the trunk of the pulmonary artery to the proximal descending aorta. It allo ...

from closing, allowing mixing of the pulmonary and systemic circulations, but prostaglandin E1 can be dangerous as it can cause

apnea Apnea, BrE: apnoea, is the temporal cessation of breathing. During apnea, there is no movement of the muscles of inhalation, and the volume of the lungs initially remains unchanged. Depending on how blocked the airways are ( patency), there ...

. Another example of preliminary treatment is

heart catheterization Cardiac catheterization (heart cath) is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes. A common example of cardiac catheterization is coronary catheterization tha ...

to evaluate the defect or defects of the heart; this procedure is much more invasive. Ultimately, however, the individual will need to have a series of surgeries to improve the blood flow permanently. The first surgery will likely be performed shortly after birth. A shunt can be created between the aorta and the pulmonary artery to help increase blood flow to the lungs. As the child grows, so does the heart and the shunt may need to be revised in order to meet the body's requirements. Fontan procedure

The type of surgery recommended depends on the size of the

and the

, if the right ventricle is small and unable to act as a pump, the surgery performed would be the

Fontan procedure The Fontan procedure or Fontan–Kreutzer procedure is a palliative surgical procedure used in children with univentricular hearts. It involves diverting the venous blood from the inferior vena cava (IVC) and superior vena cava (SVC) to the pulmon ...

. In this three-stage procedure, the

right atrium The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves. There are two atr ...

is disconnected from the pulmonary circulation. The systemic venous return goes directly to the lungs, by-passing the heart. Very young children with elevated pulmonary vascular resistance may not able to undergo the Fontan procedure. Cardiac catheterization may be done to determine the resistance before going ahead with the surgery.

Prognosis

The prognosis for pulmonary atresia varies for every child, if the condition is left uncorrected it may be fatal, but the prognosis has greatly improved over the years for those with pulmonary atresia. Some factors that affect how well the child does include how well the heart is beating, and the condition of the blood vessels that supply the heart. Most cases of pulmonary atresia can be helped with surgery, if the patient's

is exceptionally small, many surgeries will be needed in order to help stimulate normal circulation of blood to the heart. If uncorrected, babies with this type of

congenital heart disease A congenital heart defect (CHD), also known as a congenital heart anomaly and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular ...

may only survive for the first few days of life. Many children with pulmonary atresia will go on to lead normal lives, though complications such as

endocarditis Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or the ...

stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...

and

seizures An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or neural oscillation, synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much o ...

are possible.

References

External links

{{Medicine Congenital vascular defects