Neonatal arterial truncus causes serious symptoms and treatment

Truncus arteriosus is considered one of the most serious congenital heart defects that appears from birth, in which a baby is born with a single large blood vessel instead of two separate arteries. This leads to the mixing of oxygen-rich and oxygen-poor blood within the body. Although this condition may sound frightening to parents when first diagnosed, major advances in modern cardiac surgery have significantly improved survival and treatment outcomes, especially with early detection and timely intervention.In this Dalili Medical article, we will take a simplified and comprehensive journey to understand this condition, starting from its causes and symptoms, through diagnosis and treatment methods, and finally the recovery process and success rates after surgery, to provide a clear and reassuring picture for every parent seeking knowledge and peace of mind.

What is Truncus Arteriosus?
Truncus arteriosus is a rare and serious congenital heart defect present at birth, in which a baby is born with a single large blood vessel coming out of the heart instead of two separate arteries—the aorta and the pulmonary artery. This defect causes oxygen-rich and oxygen-poor blood to mix, resulting in reduced oxygen delivery to the body’s tissues. As a result, affected infants may develop symptoms such as bluish skin (cyanosis), difficulty breathing, and heart failure, and the condition usually requires early surgical intervention to correct the defect.

Is truncus arteriosus a serious condition?
Yes, truncus arteriosus is considered one of the most serious congenital heart defects if left untreated. It can lead to severe oxygen deficiency, heart failure, breathing difficulties, and poor growth in infants. However, with early diagnosis and surgical repair, outcomes have significantly improved, and many children can go on to have near-normal growth and development.

Is truncus arteriosus genetic?
In some cases, truncus arteriosus may be associated with genetic or chromosomal abnormalities. However, many cases occur sporadically without a clear hereditary cause. Therefore, it is not always considered a strictly genetic condition.

Can truncus arteriosus be detected during pregnancy?
Yes, truncus arteriosus can often be detected during pregnancy using detailed prenatal imaging, including:

Detailed ultrasound examination
Fetal echocardiography

These tests are very important for early diagnosis and planning postnatal management.

Is surgery the only treatment?
Yes, surgery is the main and definitive treatment for truncus arteriosus. The operation is usually performed early in life to separate oxygenated and deoxygenated blood flow and restore proper heart circulation.

⏱️ When is surgery performed?
In most cases, surgery is done within the first weeks of life. Delaying treatment can lead to serious complications such as heart failure and pulmonary hypertension.

Can a child live a normal life after treatment?
In many cases, after successful surgery and regular follow-up, children can live a near-normal life. Improvements usually include:

Better breathing and feeding
Improved growth and development
Regular cardiology follow-up

Some children may need additional procedures later in life as they grow.

Can the condition come back after surgery?
The original defect does not return after surgical repair. However, some children may need future interventions, such as:

Replacement of the conduit or valve used in surgery as the child grows
Additional corrective procedures to maintain heart function

Types of Truncus Arteriosus

Truncus arteriosus is classified into several types based on how the pulmonary arteries arise from the main vessel. This classification helps determine severity and surgical planning.

Type I

The most common type. A single pulmonary artery arises from the truncus and then divides into the right and left pulmonary arteries.

Type II

Both pulmonary arteries arise separately but very close to each other from the truncus.

Type III

Both pulmonary arteries arise separately but from more distant locations on the truncus.

Type IV (obsolete classification)

Previously included in the classification but no longer considered a true type of truncus arteriosus. It is now classified separately as pulmonary atresia with major aortopulmonary collateral arteries (MAPCAs).

Causes of Truncus Arteriosus

Truncus arteriosus occurs due to abnormal development of the heart during early fetal life, leading to failure of the truncus arteriosus to divide into the aorta and pulmonary artery.

1. Developmental heart defect (main cause)

Failure of the truncus arteriosus to separate into two vessels
Abnormal formation of the ventricular septum
Occurs very early in pregnancy, often before the mother knows she is pregnant

2. Genetic factors

It may be associated with genetic syndromes such as:

DiGeorge syndrome

3. Maternal infections during pregnancy

Certain infections may increase risk, such as:

Rubella (German measles)

4. Exposure to harmful substances

Risk may increase with:

Smoking during pregnancy
Alcohol consumption
Unprescribed medications

5. Maternal chronic diseases

Such as:

Uncontrolled diabetes during pregnancy

6. Unknown causes

In many cases, no clear cause is identified.

Symptoms and complications of truncus arteriosus in children

Truncus arteriosus is a serious congenital heart defect that affects blood flow between the heart and lungs, leading to low oxygen levels in the body.

Early symptoms (newborn period)

Rapid or difficult breathing
Poor feeding and fatigue during feeding
Poor weight gain
Bluish skin discoloration (cyanosis), especially lips and nails
Excessive sweating, especially during feeding
Rapid heart rate
General weakness and lethargy

Severe cases (if untreated)

Heart failure
Fluid retention and swelling
Recurrent chest and lung infections

Complications of truncus arteriosus

1. Low oxygen levels (hypoxia)

Due to mixing of oxygenated and deoxygenated blood, leading to:

Cyanosis
Chronic fatigue

2. Heart failure

The heart works harder than normal, which may cause:

Enlarged heart
Reduced pumping efficiency
Progressive heart failure if untreated

3. Pulmonary hypertension

Increased blood flow to the lungs leads to elevated pressure in the pulmonary arteries. If not treated early, this condition can become severe and life-threatening.

4. Delayed growth and development

Due to low oxygen levels and poor feeding, affected infants may experience:

Poor weight gain
Delayed motor and developmental milestones

5. Recurrent chest infections

Children with truncus arteriosus are more prone to respiratory infections, such as:

Bronchitis
Recurrent pneumonia

6. Risk of heart infection

There is an increased risk of infective endocarditis (infection of the heart lining), which is a serious complication.

7. Advanced complications if treatment is delayed

If not treated early, the condition may lead to:

Severe deterioration of heart and lung function
Difficulty in performing surgical repair later
Life-threatening outcomes in advanced stages

Diagnosis of Truncus Arteriosus

Truncus arteriosus can often be detected early after birth, and in some cases even during pregnancy.

1. Clinical suspicion

Doctors may suspect the condition when a newborn shows:

Cyanosis (bluish skin discoloration)
Difficulty breathing
Poor feeding
Failure to gain weight properly

2. Diagnostic tests

1. Echocardiography (Cardiac ultrasound)

The most important and accurate diagnostic tool.

It helps to:

Clearly visualize heart structures
Confirm the presence of a single arterial trunk instead of two separate arteries
Assess blood flow direction within the heart

2. Chest X-ray

Used to evaluate:

Enlarged heart
Condition of the lungs and pulmonary blood flow

3. Electrocardiogram (ECG)

Records the electrical activity of the heart and may show:

Signs of cardiac strain
Possible heart enlargement

4. Cardiac catheterization (in selected cases)

Used for more detailed assessment when needed.

It helps to:

Measure pressures in the heart and lungs
Provide precise anatomical and hemodynamic information for surgical planning

5. Prenatal diagnosis

Fetal echocardiography during pregnancy can detect the condition early, allowing:

Early planning of postnatal care
Delivery in a specialized cardiac center

Medical treatment of truncus arteriosus

Medical treatment is an important supportive step, but it must be clearly stated that:

❗ Medication is not a definitive cure
❗ Surgery is the only definitive treatment
❗ Drugs are used mainly for stabilization before and after surgery

Goals of medical treatment

Reduce the workload on the heart
Prevent or treat heart failure
Reduce fluid overload in the body
Improve breathing and oxygenation

Main medications used

1. Diuretics

Examples:

Furosemide

How they work:

Help remove excess fluid from the body
Reduce lung congestion

Benefits:

Easier breathing
Reduced strain on the heart

2. Medications to support heart function

Example:

Digoxin

How it works:

Improves the strength of heart contractions

Used in:

Heart failure
Reduced cardiac performance associated with truncus arteriosus

Diagnosis of Truncus Arteriosus

Truncus arteriosus is a congenital heart defect that can often be detected early after birth, and in some cases may even be diagnosed during pregnancy.

1. Clinical suspicion

Doctors may suspect truncus arteriosus when a newborn presents with:

Cyanosis (bluish discoloration of the skin)
Difficulty breathing
Poor feeding
Failure to gain weight properly

2. Diagnostic methods

1. Echocardiography (cardiac ultrasound)

The most important and accurate diagnostic tool.

It helps to:

Clearly visualize the heart structure
Detect a single large arterial trunk instead of two separate arteries
Assess blood flow direction within the heart

2. Chest X-ray

Used to evaluate:

Heart size (often enlarged)
Lung condition and pulmonary blood flow

3. Electrocardiogram (ECG)

Measures the electrical activity of the heart and may show:

Signs of cardiac strain
Possible heart enlargement

4. Cardiac catheterization (in selected cases)

Used when more detailed information is needed.

It helps to:

Measure pressures inside the heart and lungs
Provide detailed anatomical and functional data for surgical planning

5. Prenatal diagnosis

Fetal echocardiography during pregnancy can detect the condition early, allowing:

Early planning of treatment after birth
Delivery in a specialized cardiac center

Medical treatment of truncus arteriosus

Medical treatment is an important supportive step, but it is essential to understand that:

❗ Medication is not a definitive cure
❗ Surgery is the only definitive treatment
❗ Medications are used only for stabilization before or after surgery

Goals of medical treatment

Reduce the workload on the heart
Prevent or manage heart failure
Reduce fluid overload in the body
Improve breathing and oxygen levels in the blood

Main medications used

1. Diuretics

Example:

Furosemide

How it works:

Helps the body remove excess fluid
Reduces lung congestion

Benefits:

Easier breathing
Reduced strain on the heart

2. Cardiac support medications

Example:

Digoxin

How it works:

Strengthens heart muscle contractions

Used in:

Heart failure
Reduced heart pumping efficiency associated with truncus arteriosus

3. ACE inhibitors

Examples:

Captopril

How it works:

Dilates blood vessels
Lowers blood pressure

Benefits:

Reduces workload on the heart
Improves blood circulation

4. Pulmonary hypertension medications

In some cases, doctors may prescribe medications to:

Lower pulmonary artery pressure
Improve oxygen levels in the blood

These are selected carefully depending on the child’s condition.

5. Oxygen therapy

Although not a medication, it is an essential part of treatment.

Benefits:

Improves oxygen levels in the blood
Reduces cyanosis
Supports breathing in severe cases

Important notes

❗ 1. Medications are not a substitute for surgery
Surgery remains the only definitive treatment for truncus arteriosus.

❗2. Importance of close medical follow-up

Medication doses are determined according to:

The child’s body weight
The severity of the condition
The body’s response to treatment

Any adjustment must be made only under medical supervision.

❗3. Possible side effects

Side effects may include:

Low blood pressure
Irregular heart rhythm
Loss of electrolytes (especially with diuretics)

⏱️ When is medical treatment started?

Medical treatment is usually started immediately after diagnosis, especially if the infant shows:

Difficulty breathing
Poor feeding
Failure to gain weight
Signs of heart failure

Surgical treatment of truncus arteriosus

Truncus arteriosus is a serious congenital heart defect that cannot be cured with medication alone, therefore:

❗ Surgery is the main and almost definitive treatment
❗ It is usually performed within the first weeks of life to prevent complications

1. Complete repair surgery (primary correction)

This is the main and most important operation.

✳️ Surgical steps:

Separation of pulmonary arteries
The arteries carrying blood to the lungs are separated from the main vessel.
Closure of the ventricular septal defect (VSD)
A patch is used to close the hole between the ventricles.
Reconstruction of pulmonary blood flow
A new pathway is created using:
- A synthetic tube, or
- A biological conduit
Restoration of normal circulation
- Oxygen-rich blood goes to the body
- Oxygen-poor blood goes to the lungs

⭐ Benefits:

Curative treatment of the defect
Significant improvement in breathing
Reduced risk of heart failure

2. Right ventricle to pulmonary artery conduit (RV–PA conduit)

This is an essential part of the repair, sometimes mentioned separately.

✳️ Concept:

A tube is placed between the right ventricle and the pulmonary artery
It allows blood to flow normally to the lungs

⚠️ Pros and cons:

✔ Improves blood flow to the lungs
❌ May need replacement as the child grows

3. Staged surgery

Used in rare or late-diagnosed cases.

✳️ Concept:

Treatment is done in two steps:

First stage:

Reduce pressure on the lungs
Example: pulmonary artery banding in selected cases

Second stage:

Complete surgical repair after stabilization

⚠️ Note:
This approach was more common in the past and is now less frequently used due to early complete repair.

4. Heart transplantation

A very rare option.

✳️ When used:

Severe complex cases
Failure of previous surgical repairs

⚠️ Challenges:

Limited donor availability
Lifelong immunosuppressive therapy

5. Additional surgeries after primary repair

Some children may need further procedures such as:

Conduit replacement (since it does not grow with the child)
Valve repair if regurgitation occurs
Pulmonary artery interventions to improve function

⏱️ Timing of surgery

Best timing: within the first 2–6 weeks of life
Delaying surgery may lead to:
- Heart failure
- Severe pulmonary hypertension
- Increased complications

Recovery after truncus arteriosus repair

Recovery time varies depending on the child’s condition, complications, and surgical outcome.

1. Hospital recovery phase

⏱ 7–14 days (typically)

During this period:

2–5 days in intensive care
Continuous monitoring of heart and breathing
Temporary mechanical ventilation may be needed
Medications to support heart function are given

2. Recovery after discharge

⏱ 4–8 weeks

During this phase:

Gradual return to feeding
Wound healing
Progressive improvement in activity
Regular cardiology follow-up

3. Full cardiac recovery

⏱ 3–6 months

Improvements include:

Better heart function
Easier breathing
Gradual disappearance of cyanosis
Improved growth and weight gain

⚠️ Factors affecting recovery

Age at surgery
Pre-existing complications
Heart muscle strength
Pulmonary hypertension
Surgical success

⭐ Signs of good recovery

Improved breathing
Steady weight gain
Increased activity
Normal skin color
Reduced sweating during feeding

⚠️ Warning signs (seek medical help immediately)

Severe breathing difficulty
Return of cyanosis (blue lips/skin)
Persistent fever
Poor feeding
Extreme lethargy or reduced activity

Prevention of truncus arteriosus

Truncus arteriosus is a congenital heart defect that occurs due to abnormal early heart development, where the main artery fails to divide into the aorta and pulmonary artery.

Although there is no 100% guaranteed prevention, risk can be reduced through several important steps.