Tricuspid Atresia
Explanation | Signs and Symptoms | Diagnosis | Treatments | Treatment Results
What is Tricuspid Atresia?
Tricuspid atresia is a type of congenital heart disease in which the valve between the right atrium and right ventricle fails to develop.
Blood that returns from the body to the right atrium cannot directly enter the right ventricle, and must pass through a hole in the atrial septum (atrial septal defect) into the left atrium and then the left ventricle.
There are several anatomic variations that influence the symptoms and course of treatment in any given patient. There may be a hole in the ventricular septum, called a ventricular septal defect (VSD).
The aorta and pulmonary artery may be normally positioned and aligned with the appropriate ventricle (as shown in illustration), or they may be reversed, a condition called transposition of the great arteries.
If there is no ventricular septal defect or only a small one, and the great arteries are normally positioned, blood flows from the left ventricle out the aorta to the body. In this situation very little, if any, blood can get to the lungs resulting in very low oxygen levels in the infant.
In a newborn baby, blood can reach the lungs to pick up oxygen as long as a connection between the aorta and pulmonary artery called the ductus arteriosus remains open.
The "ductus" is an important vessel while the baby is still in the womb because it allows the blood from the baby's heart to return to the placenta, which does the job of the lungs before birth. This vessel is exquisitely sensitive to oxygen; when the baby is born, it typically narrows down (or closes completely) after 24 to 48 hours in response to the oxygen levels in the air breathed by the child. A medication called prostaglandin (because it was originally derived from the prostate gland) can keep this important vessel open after birth.
If there is a ventricular septal defect and normally related great arteries, blood from the left ventricle can reach the lungs through the ventricular septal defect. This channel is often very narrow, and the right ventricle very underdeveloped, so a less than normal amount of blood goes to the lungs.
Finally, if there is transposition of the great arteries, blood reaches the lungs easily because the pulmonary artery is directly connected to the left ventricle. Blood can only reach the body through the ductus arteriosus or the ventricular septal defect if there is one.
Return to Top
Tricuspid Atresia signs and symptoms
The signs and symptoms of tricuspid atresia depend on the presence and size of the ventricular septal defect, and the relationship of the great arteries.
Most commonly, the great arteries are normally related and there is either no ventricular septal defect, or only a small ventricular septal defect.
In this case, the newborn baby with tricuspid atresia will have a low oxygen level and a dusky color, or cyanosis. The cyanosis may be noted at birth, or may only become evident after several days when the ductus arteriosus closes. The less blood that goes to the lungs, the worse the cyanosis will be.
If the cyanosis is severe enough, the baby can develop symptoms of poor oxygenation such as fast breathing or poor feeding.
Occasionally, there is an increased amount of blood flow to the lungs and the child will only be mildly cyanotic, but will likely develop congestive heart failure because of the extra work the heart needs to do to pump the extra blood to the lungs.
The symptoms of congestive heart failure are fast breathing, fast heart rate, sweating with feeds and poor weight gain. If there is transposition of the great arteries, the presenting symptoms are related to low blood flow through the aorta and out to the body. This results in low blood pressure, fast breathing, poor feeding, cold, clammy hands and feet, and a pale, gray color. Infants presenting with these symptoms are critically ill and require emergency medical attention.
Return to Top
Tricuspid Atresia Diangosis
Babies with tricuspid atresia may or may not have a heart murmur. The amount of oxygen in the blood can be easily and painlessly measured using a machine called a "pulse oximeter."
Based on the symptoms reported by the parents and the physician's examination of the child, the physician will be prompted to order further tests to evaluate the heart.
The diagnosis of tricuspid atresia, and the associated specific problems such as a ventricular septal defect or transposition of the great arteries, can be very accurately diagnosed by echocardiography. This involves using an ultrasound machine to make pictures of the heart and to show the direction and, in some cases, the amount of blood flow through various parts of the heart and blood vessels.
A chest X-ray and electrocardiogram will often be performed as well.
Return to Top
Tricuspid Atresia treatment
The diagnosis of tricuspid atresia with too little blood flow to the lungs or to the body requires immediate medical treatment.
In a newborn baby (less than 1-2 weeks old), a medication called prostaglandin E1 can be given intravenously to reopen the connection (ductus arteriosus) between the pulmonary artery and aorta and improve blood flow to the lungs or body.
Children with tricuspid atresia and too little pulmonary blood flow will require surgery to establish a connection between the arteries to the body and the arteries to the lungs. This type of operation is call a modified Blalock-Taussig (BT) shunt, and involves the placement of a small Gore-tex tube between the artery to the arm (subclavian artery) and the arteries to the lungs.
If the problem is too much pulmonary blood flow (tricuspid atresia with a large ventricular septal defect), blood flow to the lungs will usually need to be limited to protect the lungs from becoming damaged from too much blood flow.
This can be accomplished by placing a band around the pulmonary artery so that it is more difficult for blood to go to the lungs.
Finally, if the problem is inadequate blood flow out the aorta (tricuspid atresia with ventricular septal defect and transposition of the great arteries), blood from the normal size left ventricle will need to be routed to the aorta, and the aorta will usually need to be reconstructed.
Pulmonary blood flow can then be established by placement of a modified BT shunt. This is essentially the Norwood procedure used for hypoplastic left heart syndrome.
Whatever operation is necessary in the newborn period, children can expect to undergo further heart surgery by the age of 3-6 months. This is true even in children who have neither too much nor too little pulmonary or systemic blood flow in the newborn period and therefore did not require any surgery at that time.
The operation at 3-6 months is called a Bi-directional Glenn. The superior vena cava is detached from the heart and connected directly to the pulmonary artery and the BT shunt is removed.
This allows blood from the body to flow directly to the lungs to pick up oxygen without having to be pumped by the heart. It also prevents blood that already has oxygen from returning to the lungs, and thereby keeps the heart from doing unnecessary work.
After this operation, however, there is still blood returning from the body through the inferior vena cava going directly back to the body without first passing through the lungs. Because of this, the cyanosis will persist.
Between the ages of 2 and 5 years, children with tricuspid atresia will be ready for the third operation required to optimize their circulation.
This operation is called the Fontan procedure, and involves connection of the inferior vena cava directly to the pulmonary artery, thereby forcing all blood returning from the body to pass through the lungs and pick up oxygen before being pumped to the body. This results in establishment of a normal color in the skin and lips.
Return to Top
Tricuspid Atresia treatment results
The results of this staged approach to the child with tricuspid atresia are generally good, with an expected survival of all three stages of 75 percent to 95 percent depending on the exact malformations and surgery for any given individual.
The long-term quality of life following the Fontan operation is also generally good, but several complications may occur. These include heart rhythm problems requiring medication or placement of a pacemaker.
Patients may also experience lung problems resulting in a decrease in oxygen in the blood, or digestive problems caused by loss of protein in the stool resulting in swelling and water retention. For a minority of patients, heart and possibly lung transplantation later in life may be necessary.
You must have Macromedia Flash Player installed on your computer to view many of the files in the Heart Center Encyclopedia. You can Macromedia Flash Player at Macromedia's web.
Rev. 9/06
