Transposition of the great vessels (TGV) is a rare, but serious, congenital heart defect, meaning the child developed the condition prior to birth. The condition involves the two main vessels and the heart that carry blood away. The defect occurs during the development of the heart when the pulmonary artery and aorta are switched (transposed). The condition is often referred to as congenital heart defect-transposition, birth defect-transposition, cyanotic heart disease-transposition, TGA, and d-TGA.
The transposed vessels can cause a variety of complications that include arteriovenous discordance, ventriculoarterial, and arteriovenous and produce significant effects on the body including blood flow circulation interruption, changes in blood pressure, and the degree of misplacement on vessels in the heart muscle.
- Who Is at Risk for Transposition of the Great Vessels?
- Common Symptoms
- Diagnosing Transposition of the Great Vessels
- Treating the Condition
Who Is at Risk for Transposition of the Great Vessels?
Because the condition is caused by a congenital heart defect, the baby is born with the problem that developed during pregnancy. However, there are specific known risk factors that are likely associated with transposition of the great vessels. These include:
- Diabetes – Pregnant mothers with pre-existing diabetic conditions have an increased potential risk of the child developing transposition of the great vessels.
- Age – Pregnant mothers older than 40 years of age have an increased potential risk of the child being born with this condition.
- Excessive Alcohol Consumption
- Poor Prenatal Nutrition – Maintaining four nutrition while pregnant can increase the chance of the child being born with TGV.
- The mother having some viral illness, like rubella, while pregnant.
What Causes Transposition of the Great Vessels?
Transposition of the great vessels is the second leading type of cyanotic heart defect. This defect is different than normal development, where oxygen-rich blood delivered to tissues and organs through the arteries before returning to the heart through the great vessels. At this point, the blood enters the right side of the heart and pulmonary artery before returning to the lungs for more oxygen. During this process, the flow of blood enters the left side of the heart before moving through the aorta out to the body.
However, if the child is born with transposition of the great vessels, the blood instead enters the lungs to gather oxygen and then returns to the heart before flowing back to the lungs and never reaching the rest of the body. The lack of oxygen out to the body causes significant problems almost immediately after birth. The child will experience major symptoms if the size and type of heart defect are serious. The condition can cause patent ductus arteriosus, ventricular septal defect, or atrial septal defect.
The most common symptoms associated with transposition of the great vessels include:
- Cyanosis, where the skin takes on a bluish tint color due to the lack of oxygen reaching tissue and organs
- Poor feeding
- Shortness of breath
- Clubbed toes or fingers
Diagnosing Transposition of the Great Vessels
The signs and symptoms associated with transposition of the great vessels are usually obvious once the child was born. During the initial physical examination after birth, the health care provider will likely detect the child's heart murmur after using a stethoscope to listen to the chest. In addition, there may be a noticeable blue color appearing on the skin and mouth that is a sign of a lack of oxygen.
The doctor might suspect that the child was affected by some type of heart condition. If so, the doctor will likely recommend a variety of tests to gather enough information to verify the presence of the transposition of great vessels defect. These procedures and tests would likely include:
- Echocardiogram (or possibly Fetal Echocardiogram) – Sometimes, the doctor may suspect of the child has developed transposition of the great vessels and order a fetal echocardiogram, or sonic waves can create a visual image of the heart functioning while the child was still in utero. If not, an echocardiogram can be performed after the child is born to help produce visual imagery on the functioning of the heart and the size of the problem.
- Cardiac Catheterization – The doctor may order a cardiac catheterization, where a thin, flexible catheter (tube) is inserted into the child's leg and threaded up through a vein into the heart muscle to provide a visual image of any problem occurring on the inside of the heart.
- ECG (electrocardiogram) – This test provides valuable insight on the electrical activity of the heart muscle and how it is functioning normally and under stress. The results of the test help verify the condition and provide information on the best form of treatment, which will likely involve a surgical repair.
- Pulse Oximetry – The medical team will attach a device to the baby's finger to help record the level of blood reaching the ends of the hands after it leaves the heart and enters the lungs to receive oxygen.
- Chest X-Ray – Although this image does not provide a verification avoid heart defect including transposition of the great vessels, it can provide visual images of the defect, its location, size, and any damage it might have caused to the interior of the heart.
Not all diagnoses of transposition of the great vessels are made while the child was in the hospital. It may be that the child developed one or more symptoms listed above after being sent home from the hospital. If a noticeable blue tint appears on the child skin, or they developed shortness of breath, or are feeding poorly, it is necessary to seek out immediate medical attention. This will ensure that the condition does not get worse or claim the life of the child.
Treating the Condition
If the doctor suspects the child was suffering from a transposition of the great vessels immediately after their birth, they will likely prescribe prostaglandin, through an intervenous (IV) line. This drug can assist the body and maintaining an open blood vessel (ductus arteriosus) to allow mixing of blood circulation until the defect can be repaired.
The doctor may recommend a balloon atrial septectomy, where a flexible, thin, long tube is inserted to create a hole in the atrial septum. This will allow the flow of blood to mix in the heart to provide more oxygen to the body.
Next, the doctor will likely perform an arterial switch surgical procedure that permanently corrects the defect. The surgery is usually performed at some point in the first week after the baby's birth and switches the great vessels and reposition them to ensure they function normally.
The symptoms associated with transposition of the great vessels will improve or disappear after the surgical procedure corrects the defect. Many times, the young child who has undergone the switch procedure will never have another symptom and can live out their lives normally. However, if the defect is not corrected through surgery, the life expectancy of the newborn is reduced to months.
If the child is displaying any signs or symptoms associated with transposition of the great vessels, it is important to seek out immediate medical attention. Without help, the child can easily die due to a lack of oxygenated-rich blood reaching every cell of the body.