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Truncus Arteriosus

Last updated Dec. 24, 2018

Approved by: Krish Tangella MD, MBA, FCAP

Centers for Disease Control and Prevention (CDC)

In Truncus Arteriosus, there may also be a large hole present between the two ventricles, called as a ventricular septal defect (VSD).


What are the other Names for this Condition? (Also known as/Synonyms)

  • Common Arterial Trunk
  • Persistent Truncus Arteriosus

What is Truncus Arteriosus? (Definition/Background Information)

  • Truncus Arteriosus is a rare, congenital heart disorder (present at birth), characterized by the presence of a single blood vessel to carry blood to the lungs (pulmonary artery) and to the rest of the body (aorta), instead of two separate vessels for the lungs and the body
  • In this abnormality, the Truncus Arteriosus (primitive part of fetal heart) fails to divide into the pulmonary artery and the aorta and they have single origin from the heart
  • Generally, the blood follows the body-heart-lungs-heart-body cycle. But, when the heart has a Truncus Arteriosus abnormality, no specific path can be followed by blood; the oxygen-rich blood and the oxygen-poor blood gets mixed up with each other, resulting in serious circulatory abnormalities
  • Normally there are two blood vessels, the aorta and the pulmonary artery which come out of the heart. The function of the pulmonary artery is to carry oxygen-poor blood to the lungs; the aorta is responsible for carrying oxygen-rich blood to the rest of the body. But, in Truncus Arteriosus, the  wall that divides the two  chambers of the heart is absent, resulting in the mixture of oxygen-rich and oxygen-poor blood
  • In a normally healthy individual, the pulmonary artery comes out from the right ventricle and the aorta comes out from the left ventricle. However, in this heart condition, a single artery comes out of the ventricle. In Truncus Arteriosus, there may also be a large hole present between the two ventricles, called as a ventricular septal defect (VSD)
  • The common signs and symptoms associated with Truncus Arteriosus include bluish discoloration of the skin, breathing difficulties, irregular heartbeat, and poor growth and development. It could present complications such as increased blood pressure in the lung (pulmonary hypertension), enlargement of the heart (cardiomegaly), and heart failure (cardiac failure)
  • Currently, surgical repair is the best available treatment for Truncus Arteriosus. With recent advancements in surgery, the prognosis is generally good, after a successful surgical intervention

Who gets Truncus Arteriosus? (Age and Sex Distribution)

  • Truncus Arteriosus is a congenital condition, which is present at birth. It is identified either at the time of birth, or during the first few days of life
  • No gender, race, or ethnic predominance is observed
  • The condition affects both boys and girls equally

What are the Risk Factors for Truncus Arteriosus? (Predisposing Factors)

Risk factors associated with Truncus Arteriosus include:

  • Viral illness during pregnancy
  • Uncontrolled diabetes, the use of certain medications, and smoking during pregnancy can increase the risk
  • Chromosomal disorder such as DiGeorge’s syndrome (velocardiofacial syndrome), which is observed in about 20% of the infants with Truncus Arteriosus

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Truncus Arteriosus? (Etiology)

The exact cause of Truncus Arteriosus is not known, but the process of disease development occurs in the following manner:

  • When the fetus develops during pregnancy, the heart starts developing with a single large blood vessel, which starts from the Truncus Arteriosus
  • If the fetus development is normal, then the truncus will divide into two arteries as:
    • Pulmonary artery , attached to the right bottom ventricle of the heart and carrying oxygen-poor blood to the lungs
    • Aorta, which is normally attached to the left bottom ventricle of the heart, and carries oxygen-rich blood to various parts of the body
  • However, due to certain adverse health factors, the partition that divides the aorta and pulmonary arterial trunk does not form and this condition is termed as Truncus Arteriosus
  • As a result of this abnormality, both oxygenated blood and deoxygenated blood mixes with each other and flows into the common trunk, which leads to more blood being pumped back into the lungs, resulting in complications such as respiratory defects

What are the Signs and Symptoms of Truncus Arteriosus?

The signs and symptoms of Truncus Arteriosus may include:

  • Cyanosis or blue discoloration of the skin
  • Under-development and growth
  • Dyspnea or shortness of breath
  • Tachypnea or rapid breathing
  • Arrhythmia or irregular heartbeats
  • Diaphoresis or excessive sweating
  • Poor appetite
  • Feeling sleepy or increased fatigue

How is Truncus Arteriosus Diagnosed?

The diagnosis of Truncus Arteriosus may involve:

  • A medical history of the infant regarding its height, weight, and head circumference are periodically recorded and checked to find if there is any delay in growth
  • The physician will check to hear the babies’ lungs to listen to the breathing pattern, and if there is an excess accumulation of fluid in the lungs
  • The physician will also undertake a through heart examination to observe any abnormalities such as irregular heartbeat, abnormal whooshing sounds called heart murmurs, etc.

Echocardiogram:

  • The structure and functioning of the heart is analyzed through this imaging study
  • Under this method, a gel is rubbed on the baby’s chest; a transducer device is pressed against the skin over the infant’s heart
  • The instrument produces sound waves and records the sound wave echoes, which are then converted into an image by the computer
  • If a child has Truncus Arteriosus, the echocardiogram will reveal the following:
    • The presence of a single large blood vessel from the heart
    • A hole in the wall that separates the left and the right ventricle
    • An abnormality in the valve between the large vessel and the ventricle
    • The quantity of blood flowing into the infant’s lungs
    • The movement of blood back and forth between the two ventricles           

X-ray: An X-ray uses electromagnetic radiation to produce images of the internal organs. A chest X-ray of the infant is usually taken to check the following:

  • Size of the heart
  • Lung abnormalities
  • Excess accumulation of fluid in the lungs

Other laboratory tests that may be required include:

  • ECG to provide details about the electrical activity of the heart
  • MRI of the heart
  • Heart cauterization

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Truncus Arteriosus?

Truncus Arteriosus can lead to the following complications:

  • Pulmonary hypertension or high blood pressure in the lungs: An increased flow of blood to the lungs makes the lungs to narrow down, increasing the blood pressure and making it difficult to pump blood into the heart
  • Cardiomegaly or enlargement of the heart: High blood pressure and increased requirement of oxygenated blood will force the heart to work much harder, causing an enlargement of the heart
  • Heart failure: Increased work load and less oxygen supply results in the heart becoming weak; this can subsequently lead to a heart failure

Complications that may develop even after successful surgery will include:

  • Progressive pulmonary hypertension
  • Regurgitation or leaky heart valves
  • Arrhythmias or disturbances in the rhythm of the heart

How is Truncus Arteriosus Treated?

Surgery is the best option for infants with Truncus Arteriosus. The treatment course may involve:

  • Certain medicines prescribed before the surgery that may include:
    • Digoxin: Also known as digitalis, it is used with the intention of improving the strength of the heart muscles that help in contraction
    • Diuretics: These are known as water pills, which are used to increase the frequency and volume of urination with the aim to reduce excess accumulation of fluid in the body            
  • The surgery may involve 3 key components that include separating the aorta and pulmonary artery, closing the ventricular defect, and establishing a connection between the heart and pulmonary artery. These surgical procedures are planned based on various factors such as the child’s health and growth
  • A lifelong follow up with a cardiologist will be required for infants who undergo corrective surgery, in order to monitor the heart function
  • The cardiologist may suggest:
    • Limited physical activity
    • Intake of antibiotics before dental procedures and other surgeries, to prevent an infection
    • Antibiotics may be recommended for a minimum period of 6 months           

How can Truncus Arteriosus be Prevented?

Currently, there are no methods to prevent the occurrence of Truncus Arteriosus. But, the following measures can help in reducing the risk:

  • If there is a family history of heart disease, or if you already have a child with Truncus Arteriosus, then advice should be sought from a cardiologist (specializing in congenital heart diseases), an obstetrician (who specializes in high-risk pregnancies), or a genetic counselor before planning for the next pregnancy
  • Vaccination before pregnancy: Certain viruses can cause serious harm during pregnancy. Getting proper vaccination for preventing such virus attacks prior to pregnancy will contribute towards the prevention of Truncus Arteriosus
  • Avoid dangerous medications during pregnancy: Certain medications may harm the fetus and hence, should be avoided
  • Taking folic acid: Tests and researches have proved that sufficient intake of folic acid decreases the risk of birth defects
  • Keeping diabetes in control: Keep the sugar level under control during pregnancy

What is the Prognosis of Truncus Arteriosus? (Outcomes/Resolutions)

  • Truncus Arteriosus is a serious heart defect that is manifested at birth; leaving the condition untreated may result in death
  • Without treatment, the mortality rate within 2-3 months after birth is almost 100%
  • With proper surgical intervention, the child can lead a near normal life, even though additional procedures may be needed as the child grows
  • Even after a successful surgery, careful follow-up and restricted/limited physical activities may be recommended by the healthcare provider

Additional and Relevant Useful Information for Truncus Arteriosus:

  • In rare cases, some individuals with Truncus Arteriosus can survive infancy without surgery and live into adulthood. However, they are commonly affected by heart failure, requiring a heart-lung transplant for remedy
  • Caring and supporting a baby with Truncus Arteriosus is a difficult task. Some suggestions for the same are:
    • Help can be sought from family members, friends, and other nonprofit organizations
    • Regularly maintain and update  the child’s medical records, which augurs well for supportive care
    • Consult with the cardiologist and prepare a list of activities that the child can participate in and follow them strictly        

What are some Useful Resources for Additional Information?


References and Information Sources used for the Article:


Helpful Peer-Reviewed Medical Articles:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: May 18, 2015
Last updated: Dec. 24, 2018