In this condition, there's no tricuspid valve. That means no blood can flow from the right atrium to the right ventricle. As a result, the right ventricle is small and not fully developed. The child's survival depends on there being an opening in the wall between the atria called an atrial septal defect (ASD) or patent foramen ovale (PFO). Otherwise, the blood returning from the body to the right atrium gets “stuck” in the right atrium and cannot return to the body. Since blood cannot get to the body, death occurs unless something is done to create an ASD or PFO.
The other problem with this defect is that no blood can get to the pulmonary arteries because the right ventricle is usually undeveloped or nonexistent. There are special cases of tricuspid atresia with a hole between the ventricles (ventricular septal defect, VSD, and/or transposition of the great arteries, TGA). These are complex heart defects with a combination of defects which can change the types of treatment needed although they are overall similar.
Typical Heart - Cross Section
Heart with Tricuspid Atresia
Tricuspid atresia is usually diagnosed in the nursery because of cyanosis (“blue baby”), difficulty breathing, or perhaps not feeding well. In some cases, the infant may not be blue but may have difficulty breathing because of too much blood flow to the lungs. There may not necessarily be an abnormal murmur on the exam, but there may be other subtle clues to the diagnosis on the examination and simple tests. The diagnosis is definitively made with echocardiography.
In the case of a very blue baby immediately after birth, prostaglandin is used to keep the ductus arteriosus open. Later, a shunt between the aorta and the pulmonary artery is placed during a surgical operation known as a Blalock Taussig Shunt or BT shunt. The shunt (or tube) takes the place of the ductus arteriosus, but cannot grow since it is usually made of synthetic material. Therefore, as the child grows, the shunt cannot supply enough blood to the lungs, and the child becomes more cyanotic. Therefore, other surgeries such as a Glenn procedure are needed to get more blood to the lungs to pick up oxygen and decrease the cyanosis.
Some children with tricuspid atresia have too much blood flowing to the lungs because of a large hole between the ventricles and a large pulmonary artery. They may need a procedure known as pulmonary artery banding or PA banding, which is like a noose around the pulmonary artery to constrict or reduce blood flow to the lungs. Eventually, children with tricuspid atresia may have a more functional repair (the Fontan procedure).
The risks of open-heart surgery always include bleeding, infection and the need for cardiopulmonary bypass. Depending on the type of surgery, special risks of injury to surrounding structures may occur.
Untreated, tricuspid atresia will usually result in death in infancy. With surgical treatment, lifestyle is fair to good, but probably not normal due to some limitation in exercise capability. This varies from patient to patient. There is the risk of the development of rhythm abnormalities, which may alter lifestyle and lifespan and may require medical or other types of treatment. If there is a residual hole allowing blue blood to go to the body (right to left shunt), there is a risk of stroke. The function of the heart may worsen over time requiring treatment with medicine or even cardiac transplantation. Similar to other heart defects, preventive measures against bacterial endocarditis are required for life. Children with tricuspid atresia should have lifelong follow up.