Truncus Arteriosus: Causes, Symptoms, and Treatment

What is Truncus Arteriosus?

Truncus arteriosus is a rare but serious congenital heart defect in which a single large arterial trunk replaces the normal aorta and pulmonary artery. This causes oxygen-rich and oxygen-poor blood to mix before leaving the heart, reducing the amount of oxygen delivered to the body and placing significant strain on the baby’s circulation.

Because the condition can quickly lead to heart failure and other severe complications, early diagnosis and prompt treatment are essential. This article outlines the causes, symptoms, diagnosis, treatment options, and long-term outlook to help parents and caregivers understand the condition and what to expect.

Truncus Arteriosus vs. Normal Heart Anatomy

In a healthy heart, the aorta and pulmonary artery carry blood away from the heart through two separate pathways, ensuring that the body receives oxygen-rich blood while the lungs receive oxygen-poor blood for reoxygenation. These distinct vessels keep circulation efficient and maintain proper oxygen supply.

In truncus arteriosus, this process is disrupted because a single large vessel—the truncal artery—leaves the heart and carries mixed blood to the lungs, body, and coronary arteries. A ventricular septal defect (VSD) is almost always present, increasing the mixing of oxygen-rich and oxygen-poor blood. As a result, the body receives less oxygen than it needs, leading to the early symptoms often seen in the first weeks of life.

Truncus Arteriosus Causes

Truncus arteriosus develops during the first eight weeks of pregnancy, when the baby’s heart is forming. Normally, one fetal vessel divides into the aorta and pulmonary artery, but in this condition the separation fails, leaving a single common vessel.

Genetic factors, family history, and certain environmental influences—such as infections, medications, or maternal health conditions—may increase the risk, though most cases occur without a clear cause.

The condition affects about 1 in 10,000 births, making it rare. It is classified as a critical congenital heart defect because prompt medical treatment is essential for survival and healthy development.

How Truncus Arteriosus Affects Blood Flow (Pathophysiology)

Understanding how truncus arteriosus disrupts circulation explains why early treatment is critical. In this condition, both ventricles pump blood into a single truncal vessel, causing oxygen-rich and oxygen-poor blood to mix.

As a result, the body receives less oxygen, leading to the bluish or grey tint seen in the skin, lips, and nails. Because there is no separate pulmonary artery, too much blood flows to the lungs, increasing pressure in the lung vessels and straining the heart.

This abnormal blood flow puts significant strain on the heart chambers and can rapidly lead to heart failure if untreated. Even the coronary arteries receive mixed blood, which may affect the heart’s own function.

Truncus Arteriosus Symptoms in Newborns and Infants

Recognising the symptoms of truncus arteriosus early helps ensure your baby receives timely medical care. Most signs appear within the first few weeks of life, as the heart struggles to deliver enough oxygen to the body.

Symptoms to watch for include:

• Cyanosis: Bluish or grayish tint to the skin, lips, or nails
• Rapid or laboured breathing
• Poor feeding or frequent breaks during feeds
• Failure to thrive: Slow weight gain or poor growth
• Excessive fatigue or unusual sleepiness
• Frequent respiratory infections
• Signs of heart failure: Swelling in the hands, feet, or face

Examination and Imaging Techniques to Diagnose Truncus Arteriosus

Diagnosing truncus arteriosus involves specialised tests that assess the heart’s structure and function. Often, an abnormal heart murmur during a routine exam prompts further evaluation.

Common diagnostic tests include:

• Echocardiogram: Detailed images of heart chambers and blood vessels
• Chest X-ray: Shows heart size and increased lung blood flow
• ECG: Evaluates heart rhythm and electrical activity
• Pulse oximetry: Measures blood oxygen levels
• Cardiac catheterisation: Assesses pressures inside heart chambers
• Cardiac MRI or CT: Provides detailed imaging of heart structure and vessel connections

Truncus arteriosus occurs in about 7 per 100,000 live births, making up less than 1% of all congenital heart defects. According to the National Institutes of Health, without early surgery, over 80% of infants die within the first year, but with timely repair, long-term survival exceeds 80%.

Truncus Arteriosus Treatment

Treatment for truncus arteriosus requires early surgical repair, usually within the first few months of life. The goal is to create separate pathways so the lungs and body receive properly oxygenated blood.

Surgeons close the VSD and use a conduit to connect the right ventricle to the pulmonary arteries, allowing oxygen-poor blood to reach the lungs while the remaining truncal vessel carries oxygen-rich blood to the body.

Before surgery, babies may need medications to manage heart failure symptoms, reduce fluid buildup, support heart function, and improve growth.

Long-Term Outlook After Truncus Arteriosus Repair

The long-term outlook for children after truncus arteriosus repair has improved significantly with advances in surgical techniques and post-operative care. Modern survival rates exceed 85% when surgery is performed early in life at experienced centres.

Survival Rates & Reintervention Expectations

Most children will need additional procedures as they grow:

• Conduit replacement: The right ventricle–to–pulmonary artery conduit often needs replacement over time
• Valve repairs: The truncal valve may require repair or replacement later in life
• Arrhythmia treatment: Some children develop irregular heart rhythms that need management

Possible Complications if Untreated or Delayed

Without surgical repair, truncus arteriosus can cause serious, life-threatening complications:

• Pulmonary hypertension: Critically high pressure in lung blood vessels
• Heart failure: The heart can no longer pump effectively
• Irreversible lung damage: Permanent changes in lung vessels
• Growth failure: Poor weight gain and delayed development
• Death in infancy: Most untreated babies do not survive the first year

Living with Truncus Arteriosus (Children → Adults)

Children who undergo successful truncus arteriosus repair can often lead healthy, active lives with regular cardiology follow-up. Most grow and develop normally, though some may need to avoid strenuous or competitive sports based on their heart function.

Dental Care & Endocarditis Precautions

Maintaining good dental hygiene is essential for children with repaired truncus arteriosus:

• Regular dental check-ups to prevent buildup and detect issues early
• Antibiotics before certain procedures to reduce endocarditis risk
• Daily brushing and flossing to lower infection risk
• Prompt treatment of dental problems to avoid complications

Nutrition, Growth, and Development After Surgery

Many children show better growth and development after successful repair. Feeding difficulties and high energy demands may cause poor weight gain before surgery, but most children catch up afterward with proper nutrition. Working with a paediatric nutritionist can help ensure adequate calories, and some children may need high-calorie formulas or supplements during recovery.

Activity & Sports Participation

Physical activity is important after truncus arteriosus repair, with some adjustments:

• Regular exercise supports heart health and overall fitness
• Cardiologist guidance helps determine safe activity levels
• Avoid high-impact or extreme sports that may strain the heart
• Teach children to recognize fatigue and rest when needed

Transition to Adult Congenital Heart Care

As children grow into adults, their care shifts to specialists in adult congenital heart disease to ensure continuity and expertise. Ongoing monitoring remains essential, as adults may develop conduit issues, arrhythmias, or heart failure. Regular follow-ups help detect and manage these problems early.

Truncus Arteriosus and Pregnancy (Preconception Counselling)

Women with repaired truncus arteriosus should receive specialised counselling before pregnancy:

• Pre-pregnancy evaluation to assess heart function and risks
• Genetic counselling to understand the chance of congenital heart disease in the baby
• High-risk obstetric care for close monitoring throughout pregnancy
• Delivery planning ensures a safe birth with appropriate medical support.

How to Choose a Surgical Centre

Choosing the right surgical centre is crucial for achieving the best results in truncus arteriosus repair. Look for:

• Extensive experience with complex congenital heart defects, including truncus arteriosus
• Transparent survival rates and outcomes for this specific surgery
• A multidisciplinary team of paediatric cardiologists, surgeons, and ICU specialists
• Comprehensive long-term follow-up programs for continued care
• Family support services to help you navigate treatment and recovery

Questions to Ask Your Care Team

Don’t hesitate to ask your care team important questions, such as:

• What experience do you have with truncus arteriosus repairs?
• What are your survival and complication rates?
• How often do children need further surgeries?
• What long-term care will my child need?
• What support resources are available for families?
• How are emergencies or post-surgery complications handled?

When to Call the Doctor After Discharge

After surgery, seek immediate medical attention if your baby shows:

• Difficulty or rapid breathing
• Blue colouring of the lips, skin, or nails
• Poor feeding or ongoing vomiting
• Swelling of the hands, feet, or face
• Fever or signs of infection at the incision site
• Irregular heartbeats or fainting

Conclusion

Truncus arteriosus is serious but treatable. With timely surgery and lifelong follow-up in a specialised congenital heart program, most children can grow, learn, and lead active lives. If your cardiologist recommends blood tests, genetic screening, or ongoing monitoring, choosing a reliable lab ensures faster results and confident decision-making throughout your child’s care.

Metropolis Healthcare brings together 4000+ tests (including speciality testing) and comprehensive full body checkups, backed by home sample collection through 10,000 touchpoints for quick turnaround and accurate results. Booking is effortless; choose what’s convenient for you: website, call, app, or WhatsApp, and we’ll handle the rest so you can focus on your child’s recovery.

FAQs

Is truncus arteriosus curable?

Surgery corrects the circulation and relieves symptoms, but lifelong follow-up is needed. Conduits and valves may require replacement over time.

What is the survival rate after truncus arteriosus surgery?

Contemporary series from major centres report ~90–95% survival to hospital discharge; longer-term survival into adulthood is common, with variation by patient factors and valve issues.

Can truncus arteriosus be detected before birth?

Yes. Many cases are suspected on prenatal ultrasound and confirmed by fetal echocardiography, which helps plan delivery and immediate care.

Will my child need more surgeries as they grow?

Often yes. As children grow, the RV-to-pulmonary conduit may need catheter-based or surgical replacement. Your team will time these safely.

How long is the hospital stay after repair?

Stay length varies by age, anatomy, and valve repair needs. Your surgeon will discuss an expected range based on your child’s plan and recovery.

Is physical activity safe after truncus arteriosus surgery?

Most everyday activities are fine once your cardiologist clears your child. Competitive sports depend on individual heart function and rhythm status.

Does truncus arteriosus affect life expectancy?

Many patients lead active lives into adulthood. Lifelong ACHD care helps maintain heart health and address conduit/valve issues as they arise.

References

https://www.ncbi.nlm.nih.gov/books/NBK534774/

https://www.mayoclinic.org/diseases-conditions/truncus-arteriosus/symptoms-causes/syc-20364247

https://my.clevelandclinic.org/health/diseases/14785-truncus-arteriosus

https://www.hopkinsmedicine.org/health/conditions-and-diseases/truncus-arteriosus-ta