Truncus Arteriosus

Overview

• Definition: Truncus arteriosus (TA) is a rare congenital heart defect characterized by a single great artery arising from the heart, overriding a ventricular septal defect (VSD), and supplying the systemic, pulmonary, and coronary circulations. There is a single truncal valve that typically has varying degrees of insufficiency and/or stenosis.
• Epidemiology: TA accounts for approximately 0.7-1.1% of all congenital heart defects. Its incidence is estimated to be 0.03 to 0.06 per 1,000 live births. There is no significant sex predilection. TA is frequently associated with DiGeorge syndrome (22q11.2 deletion syndrome), occurring in 30-50% of cases.
• Classification: The most widely used classification system is by Collett and Edwards, based on the origin of the pulmonary arteries from the common truncal artery:
  • Type I: A single pulmonary trunk arises from the common truncus, which then branches into the right and left pulmonary arteries. This is the most common type (48%).
  • Type II: The right and left pulmonary arteries arise separately but in close proximity from the posterior aspect of the common truncus (29%).
  • Type III: The right and left pulmonary arteries arise separately and directly from the lateral aspects of the common truncus, often at some distance from each other (11%).
  • Type IV: The pulmonary arteries arise from the descending aorta (ductus arteriosus dependent pulmonary circulation). This type is now largely considered a severe form of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (MAPCAs) rather than true truncus arteriosus. A less common classification by Van Praagh emphasizes the number of truncal valve leaflets and the presence of associated VSD.

Pathophysiology

• Mechanism: TA results from the failure of the embryonic truncus arteriosus to undergo normal septation into the aorta and pulmonary artery during cardiovascular development (weeks 3-8 of gestation). This failure is often attributed to abnormal neural crest cell migration, which also explains the strong association with DiGeorge syndrome, a neural crest cell disorder. The single great artery overrides a large, unrestrictive VSD, allowing complete mixing of systemic and pulmonary venous blood.
  • Hemodynamics: In the immediate postnatal period, pulmonary vascular resistance (PVR) is high. As PVR naturally falls, blood preferentially flows into the lower resistance pulmonary circulation, leading to severe pulmonary overcirculation, pulmonary hypertension, and eventually, congestive heart failure (CHF). Systemic blood flow is maintained provided there is forward flow through the truncal valve.
  • Oxygen Saturation: Due to complete mixing, systemic arterial oxygen saturation is reduced (typically 75-90%), leading to mild cyanosis which may not be clinically apparent initially. The degree of cyanosis is initially dictated by the balance of pulmonary and systemic blood flow.
• Risk Factors:
  • Genetic/Chromosomal Syndromes: DiGeorge syndrome (22q11.2 microdeletion) is the most significant risk factor. Other associations include velocardiofacial syndrome,CHARGE syndrome, and VACTERL association.
  • Maternal Factors: Certain maternal conditions such as uncontrolled diabetes, phenylketonuria, and exposure to teratogens (e.g., alcohol, thalidomide, isotretinoin) can increase the risk of congenital heart defects, including TA, though specific strong links for TA are less defined than for some other defects.
  • Family History: A family history of congenital heart disease can slightly increase risk, suggesting a multifactorial inheritance pattern in some cases.
• Protective Factors: None specifically identified for congenital heart defects. Optimal maternal health and avoiding known teratogens during pregnancy are general preventive measures.

Clinical Presentation

Signs and Symptoms

• Cardinal Features:
  • Progressive Cyanosis: Often mild at birth, but becomes more apparent as pulmonary vascular resistance falls, typically within the first few days to weeks of life.
  • Symptoms of Congestive Heart Failure (CHF): Tachypnea, dyspnea, poor feeding, diaphoresis with feeds, failure to thrive (FTT). These typically develop within the first few weeks due to severe pulmonary overcirculation.
  • Poor weight gain/Failure to thrive: A common consequence of increased metabolic demand and poor feeding.
• Early Signs:
  • Mild cyanosis (may be subtle or missed, especially if PVR remains elevated).
  • Tachypnea and increased work of breathing within days to weeks of birth.
  • Irritability or lethargy.
• Advanced Signs:
  • Severe tachypnea and respiratory distress.
  • Hepatomegaly (sign of right heart failure).
  • Peripheral edema (less common in neonates/infants).
  • Profound failure to thrive.
  • Evidence of pulmonary vascular obstructive disease in untreated older children.
• Atypical Presentations:
  • Severe truncal valve stenosis may limit pulmonary blood flow, leading to more profound cyanosis at birth.
  • Severe truncal valve regurgitation can accelerate CHF symptoms.
  • Presentation may be delayed in cases with associated major aortopulmonary collateral arteries (MAPCAs) supplying the pulmonary circulation, which can initially restrict pulmonary flow.

Physical Examination

• Inspection:
  • Cyanosis: May be generalized and subtle to frank, especially noticeable in lips and nail beds.
  • Tachypnea: Rapid breathing, often with retractions, grunting, or nasal flaring.
  • Poor perfusion: Pale, mottled skin, delayed capillary refill.
  • Growth: Evidence of poor weight gain or failure to thrive.
• Palpation:
  • Precordial activity: Hyperdynamic precordium with a prominent apical impulse, reflecting volume overload of the left ventricle.
  • Pulses: Bounding peripheral pulses due to widened pulse pressure, often associated with truncal valve regurgitation.
  • Hepatomegaly: Liver edge palpable significantly below the costal margin, indicative of right heart failure.
• Auscultation:
  • Heart Sounds:
    • Loud, single S2 (due to the presence of a single semilunar valve) is characteristic.
    • Often a systolic ejection click from the truncal valve.
    • S3 gallop may be present with CHF.
  • Murmurs:
    • A loud, harsh systolic ejection murmur over the left sternal border and apex, due to increased flow across the truncal valve and/or the VSD.
    • A diastolic murmur (decrescendo) may be present at the left lower sternal border if truncal valve regurgitation is significant.
    • A holosystolic murmur at the lower left sternal border related to the VSD, which may be obscured by the truncal flow murmur.
    • A continuous murmur may be heard, especially over the lung fields, related to increased pulmonary blood flow.
• Special Tests: Not applicable during physical exam. Genetic testing (e.g., FISH for 22q11.2 deletion) is performed if indicated.

Diagnostic Approach

History Taking

• Key Questions:
  • Prenatal history: Any known maternal illnesses (e.g., diabetes, rubella), teratogen exposure (e.g., alcohol, specific medications)?
  • Feeding patterns: How is the infant feeding? Any difficulty latching, prolonged feeds, sweating during feeds?
  • Breathing patterns: Any rapid breathing, grunting, flaring?
  • Color changes: Any bluish discoloration of lips, nail beds, or skin, especially with crying or feeding?
  • Growth: Current weight and length; comparison to birth parameters and growth charts.
  • Family history: Any history of congenital heart disease or genetic syndromes?
  • Maternal genetic testing: Results of any prenatal chromosomal microarray or FISH for 22q11.2 deletion.
• Red Flags:
  • Rapid onset or worsening of tachypnea, respiratory distress.
  • Increasing cyanosis.
  • Poor feeding/lethargy.
  • Significant failure to thrive.
  • Any signs suggestive of sepsis, especially in patients with DiGeorge syndrome (immunodeficiency).

Laboratory Tests

• First-Line:
  • Arterial Blood Gas (ABG): To assess oxygenation, ventilation, and acid-base status. Often shows hypoxia and compensated mild metabolic acidosis.
  • Complete Blood Count (CBC): May show polycythemia in chronic hypoxemia (uncommon in infants with TA due to early surgical repair), or anemia (can exacerbate CHF symptoms).
  • Electrolytes, BUN, Creatinine: To assess renal function, especially if hypoperfusion or medication effects are concerns.
• Confirmatory:
  • Chromosomal Microarray Analysis (CMA) / Fluorescent In Situ Hybridization (FISH) for 22q11.2 deletion: Essential for all patients with TA due to high association and implications for prognosis and management (e.g., hypocalcemia, immunodeficiency).
• Monitoring:
  • Electrolytes/Calcium: Especially for patients with 22q11.2 deletion (risk of hypocalcemia).
  • CBC: To monitor for anemia or polycythemia.

Imaging

• Recommended:
  • Echocardiography (Transthoracic Echocardiogram - TTE): This is the definitive diagnostic imaging modality.
    • Findings: Visualization of a single great artery overriding a VSD, identification of the truncal valve (number of leaflets, competence), origin of pulmonary arteries from the truncus (Collett and Edwards type), presence of patent ductus arteriosus (PDA), assessment of ventricular function, chamber sizes, and estimation of pulmonary artery pressure.
  • Chest Radiograph (CXR):
    • Cardiomegaly (often significant, grade 2-3 out of 4).
    • Increased pulmonary vascular markings (due to pulmonary overcirculation).
    • Right aortic arch is present in 30-35% of TA patients, which is also associated with DiGeorge syndrome.
• Advanced:
  • Cardiac Computed Tomography Angiography (CCTA) or Cardiac Magnetic Resonance Imaging (CMRI):
    • Indicated in complex cases, pre-operatively to delineate pulmonary artery anatomy, particularly if echocardiography is equivocal or if there is suspicion of MAPCAs (especially in Type IV or difficult Type III classifications). Also useful for assessing truncal valve characteristics and ventricular function more precisely.
  • Fetal Echocardiography: Can diagnose TA prenatally, typically in the late second or third trimester. This allows for planned delivery at a specialized center and early postnatal management.

Management

Timely surgical repair is vital for survival. Without surgical intervention, most infants with TA die within the first year of life.

Acute Management

• Immediate (Pre-operative stabilization):
  • Respiratory Support: Address tachypnea and respiratory distress. Intubation and mechanical ventilation may be required if severe, often with low positive end-expiratory pressure (PEEP) to avoid overdistending the lungs.
  • Circulatory Support: Manage signs of congestive heart failure.
    • Diuretics: Furosemide (Lasix) 1-2 mg/kg/dose IV, often BID, for pulmonary edema and fluid overload.
    • Inotropes: Rarely needed pre-operatively unless severe myocardial dysfunction, which is uncommon directly from TA.
    • Maintain systemic blood pressure: If hypotension is present, address volume status carefully.
  • Maintain Pulmonary Vascular Resistance (PVR): Avoid hyperoxia, which can drop PVR too low and exacerbate pulmonary overcirculation. May require judicious use of oxygen or even maintaining a slightly higher PaCO2 ("permissive hypercapnia") to keep PVR elevated. In some centers, ventilatory strategies aim for lower oxygen saturation (e.g., 70-80%) pre-operatively.
  • Genetic Consultation: Rapid workup for 22q11.2 deletion, including FISH testing.
  • Hypocalcemia management: If 22q11.2 deletion is suspected or confirmed, monitor serum calcium levels closely. Treat hypocalcemia with intravenous calcium gluconate as needed.
• Stabilization:
  • Optimize nutritional status to improve surgical outcomes. Enteral feeding should be encouraged. May require nasogastric or orogastric tube feeding.
  • Correction of any metabolic derangements.
• Emergency: Rarely required specifically for TA unless there is acute profound heart failure, severe truncal valve regurgitation, or severe truncal valve stenosis. The main emergency is often the progression of CHF, making definitive surgery urgent rather than immediate.

Chronic Management (Post-operative and long-term)

• The goal of management is complete surgical repair in infancy. Chronic management focuses on long-term follow-up and management of residual lesions or complications.
• Pharmacological:
  • Post-operative:
    • Diuretics: May be continued for weeks to months post-operatively to manage residual fluid retention or ventricular dysfunction.
    • ACE inhibitors: Enalapril or captopril may be used for patients with residual ventricular dysfunction or systemic hypertension.
    • Antiplatelet agents: Aspirin may be used long-term in patients with history of coronary artery abnormalities or conduits prone to graft stenosis, as per surgeon preference.
    • Antibiotic Prophylaxis: Endocarditis prophylaxis is generally recommended for the first 6 months post-repair, and lifelong if there are prosthetic materials or residual defects as per AHA guidelines.
  • Long-term:
    • Medications are generally not required if repair is successful and without significant residual lesions, aside from prophylaxis.
• Non-pharmacological:
  • Nutritional Support: Crucial in the pre- and post-operative periods to ensure adequate growth and recovery.
  • Activity Restrictions: Generally no specific restrictions after successful repair, though individualized assessment is key.
  • Developmental Support: Children with complex congenital heart disease, particularly those with DiGeorge syndrome, often require developmental monitoring and early intervention therapies.
• Monitoring:
  • Lifelong follow-up with a cardiologist: Regular echocardiograms to assess ventricular function, status of the right ventricle to pulmonary artery (RV-PA) conduit (prone to stenosis/regurgitation), degree of truncal valve regurgitation (if left in place, or neoaortic valve), and pulmonary artery pressures.
  • Monitoring for RV-PA conduit stenosis/regurgitation: This is a common and almost inevitable long-term complication, often requiring re-operation or transcatheter interventions.
  • Assessment for residual VSD: Though rare after repair, can lead to persistent shunting.
  • Truncal valve/Neoaortic valve dysfunction: Surveillance for stenosis or regurgitation.
  • Assessment for pulmonary hypertension: Especially if repair was delayed or if there's significant residual defect.
  • Neurodevelopmental assessment: Essential due to the high incidence of developmental delays, particularly in patients with DiGeorge syndrome.

Treatment Algorithms

• First-Line:
  1. Diagnosis: Suspect TA based on clinical signs (cyanosis, CHF, characteristic murmur, CXR), confirm with echocardiography.
  2. Pre-operative Stabilization: Manage CHF, optimize respiratory status, rule out/manage 22q11.2 deletion associated conditions (hypocalcemia, immunodeficiency).
  3. Surgical Repair: Indicated in the neonatal period or early infancy, typically within the first few weeks of life, once stable.
     • Rastelli-type repair:
       • Closure of the VSD to direct left ventricular outflow to the truncal (now systemic aorta).
       • Disconnection of the pulmonary arteries from the common truncus.
       • Reconstruction of the right ventricular outflow tract (RVOT) with a conduit (e.g., homograft, xenograft) connecting the right ventricle to the pulmonary arteries.
     • Truncal valve repair or replacement: As needed for significant stenosis or regurgitation. The original truncal valve becomes the neoaortic valve.
• Second-Line: Not applicable for primary repair, as definitive surgical correction is the only long-term solution. Patients who are critically unwell or have severe associated anomalies may require a staged approach or palliative care decision.
• Refractory Cases:
  • Pulmonary hypertension with vascular obstructive disease: If surgery is delayed, irreversible pulmonary hypertension may develop, precluding successful repair. In such cases, lung and heart-lung transplantation may be considered, but prognosis is poor.
  • Repeated conduit failure: Requires multiple re-operations or transcatheter interventions (e.g., balloon angioplasty, stenting, valve-in-valve procedures) over the patient's lifetime.
  • Severe truncal valve regurgitation after repair: May require truncal (neoaortic) valve replacement.

Complications

• Common:
  • Right Ventricular Outflow Tract (RVOT) conduit dysfunction: Stenosis, insufficiency, calcification. This is almost universal over time, requiring re-intervention.
  • Truncal valve (neoaortic valve) regurgitation: Can develop post-operatively or worsen over time, requiring re-operation.
  • Residual ventricular septal defect (VSD): Though rare, can lead to persistent shunting.
  • Pulmonary artery branch stenosis: Can occur at anastomotic sites.
  • Arrhythmias: Less common than in some other complex CHDs, but can occur.
• Serious:
  • Pulmonary vascular obstructive disease (Eisenmenger syndrome): If surgical repair is delayed, irreversible pulmonary hypertension can develop, leading to poor prognosis and unreparability.
  • Endocarditis: Risk associated with prosthetic materials and residual lesions.
  • Sudden cardiac death: Rare, but a potential risk, often associated with severe RVOT obstruction, pulmonary hypertension, or ventricular dysfunction.
• Long-term:
  • Need for multiple re-operations: Due to conduit degeneration.
  • Neurodevelopmental delays: Often associated with DiGeorge syndrome, but also from the impact of complex congenital heart disease and surgical interventions.
  • Growth failure: Can persist despite successful repair in some cases.
  • Respiratory issues: Due to prolonged pulmonary overcirculation or pre-existing airway abnormalities (e.g., tracheomalacia in DiGeorge).

Prognosis

• Factors:
  • Time of surgical repair: Early repair (neonatal/early infancy) significantly improves prognosis and prevents irreversible pulmonary vascular disease.
  • Presence of 22q11.2 deletion (DiGeorge syndrome): Patients with DiGeorge syndrome have higher mortality, more complications (e.g., hypocalcemia, immunodeficiency, developmental delay), and often poorer long-term outcomes compared to isolated TA.
  • Truncal valve competence: Significant pre-operative truncal valve regurgitation or stenosis is a risk factor for early mortality.
  • Anatomy of pulmonary arteries: Specific challenges in Type III and IV.
  • Surgical expertise: Outcomes are better at high-volume centers with experienced surgical teams.
• Survival:
  • Untreated: Mortality is >80% by one year of age.
  • With surgical repair: Early mortality (within 30 days of surgery) ranges from 5-15% in current series, though can be higher with associated anomalies or genetic syndromes.
  • Long-term survival (20-30 years post-op): Reported to be 70-85%, but many patients require multiple re-operations.
• Quality of Life:
  • Children who survive and undergo successful repair generally have a good functional capacity.
  • Quality of life can be impacted by the need for multiple re-operations for RVOT conduit dysfunction, neurodevelopmental delays (especially with DiGeorge syndrome), and the ongoing need for specialist medical follow-up.
  • Many patients function well, attending school and leading relatively normal lives, but exercise capacity may be reduced.

Prevention

• Primary:
  • Genetic counseling: For families with a history of congenital heart disease or known genetic syndromes.
  • Maternal health optimization: Strict control of maternal diabetes and avoidance of known teratogens during pregnancy.
  • Folic acid supplementation: While primarily for neural tube defects, it also offers general protective effects against some congenital malformations.
• Secondary:
  • Prenatal diagnosis: Fetal echocardiography is instrumental in early detection, allowing for planned delivery at a tertiary care center, parent education, and preparation for early postnatal intervention. This does not prevent the defect but optimizes outcome.
  • Newborn screening: Pulse oximetry screening may detect critical congenital heart disease, though TA may initially present with mild desaturation that could be missed.
• Tertiary:
  • Early surgical repair: Within the first few weeks of life to prevent the development of irreversible pulmonary vascular disease and reduce morbidity/mortality.
  • Lifelong cardiac follow-up: To detect and manage complications (e.g., conduit stenosis, valve dysfunction) early.
  • Aggressive management of comorbidities: Especially those associated with 22q11.2 deletion (e.g., hypocalcemia, immunodeficiency, developmental issues).

Special Populations

• Pediatric:
  • Neonates/Infants: The primary surgical candidates. Management focuses on stabilization, early diagnosis of genetic comorbidities, and timely surgical repair before irreversible pulmonary vascular disease develops. High metabolic demands require aggressive nutritional support.
• Geriatric: Not applicable as TA is a congenital condition requiring repair in infancy. Unrepaired TA patients do not survive to old age. Survivors with repaired TA fall under long-term follow-up of adult congenital heart disease (ACHD) programs.
• Pregnancy:
  • Women with repaired TA can generally tolerate pregnancy well, provided there is no significant residual pulmonary hypertension, severe ventricular dysfunction, or severe valve disease.
  • Close monitoring by an ACHD cardiologist and high-risk obstetrician is essential.
  • Risk of offspring developing CHD is slightly increased (estimated 3-5%), requiring fetal echocardiogram during pregnancy.
  • Specific risks include pulmonary insufficiency after RVOT reconstruction (leading to RV dilation), and the potential for a small, restricted RVOT conduit to become relatively obstructive during pregnancy.
• Comorbidities:
  • DiGeorge Syndrome (22q11.2 deletion): Present in 30-50% of TA patients. Requires vigilant monitoring for:
    • Hypocalcemia: Can precipitate seizures, cardiac arrhythmias.
    • Immunodeficiency (T-cell defects): Increased susceptibility to infections. May necessitate T-cell count, T-cell function studies, and prophylactic antibiotics or IVIG if severe. Caution with live vaccines. Thymus transplant in severe cases.
    • Palatal abnormalities: Can cause feeding difficulties, speech problems.
    • Developmental delays: Requires early intervention services.
    • Renal anomalies: Should be screened for.
  • Other CHDs: Less common, but TA can coexist with other defects (e.g., interrupted aortic arch (particularly in DiGeorge syndrome), coronary artery anomalies), which complicates management.

Clinical Pearls

• Diagnostic:
  • A loud, single second heart sound (S2) with a prominent systolic murmur that often radiates to the lung fields in a cyanotic infant with signs of CHF is highly suggestive of truncus arteriosus.
  • Always consider 22q11.2 deletion in any infant with truncus arteriosus. Genetic testing should be pursued promptly due to significant management implications.
  • The severity of cyanosis can be mild in the neonatal period due to balanced or even increased pulmonary blood flow. CHF often defines the clinical picture.
• Treatment:
  • Timely surgical repair is critical. "Too sick to operate" is often a "too sick not to operate" scenario for TA once stabilized.
  • Aggressive management of pulmonary overcirculation pre-operatively by avoiding supplemental oxygen and carefully managing mechanical ventilation (to avoid decreasing PVR) is crucial.
  • Anticipate and plan for multiple re-operations for RVOT conduit dysfunction. Patients and families need to be educated about this lifelong aspect of care.
  • For patients with 22q11.2 deletion, a multidisciplinary approach involving cardiology, immunology, endocrinology, genetics, and developmental pediatrics is paramount.
• Pitfalls:
  • Delaying surgery: The most common and dangerous pitfall, leading to irreversible pulmonary vascular disease.
  • Missing 22q11.2 deletion syndrome: Failure to diagnose can lead to unaddressed hypocalcemia (seizures), immunodeficiency (severe infections), and lack of appropriate developmental support.
  • Misinterpreting "mild cyanosis": Can lead to a false sense of security and delay diagnosis or referral. The absence of severe cyanosis does not imply a less severe lesion in TA.
  • Over-oxygenation pre-op: Can exacerbate pulmonary overcirculation and worsen CHF.

Recent Updates

• Guidelines: Current recommendations from major cardiology societies (e.g., American Heart Association, European Society of Cardiology) emphasize early surgical repair in neonates/infants, comprehensive screening for 22q11.2 deletion, and lifelong follow-up in specialized ACHD centers.
• Evidence:
  • Improved surgical techniques: Ongoing refinements in surgical techniques and post-operative critical care have led to steadily improving outcomes, particularly in reducing early mortality.
  • Conduit innovation: Research continues into bioresorbable, growth-modifiable, or living tissue conduits to reduce the need for multiple re-interventions for RVOT reconstruction. Early experimental results are promising but not yet widely implemented in clinical practice.
  • Long-term outcomes of 22q11.2 deletion: Growing body of evidence highlights the persistent neurodevelopmental, psychiatric, and immunologic challenges faced by these patients into adulthood, reinforcing the need for comprehensive, multidisciplinary care from early life.
• Controversies:
  • Optimal timing of RVOT conduit replacement: Decisions regarding prophylactic vs. symptomatic conduit replacement, and balancing surgical risk vs. benefits of improved hemodynamics.
  • Management of truncal valve regurgitation: Whether to preserve, repair, or replace the truncal valve during initial repair, especially in mild to moderate cases. The long-term implications of leaving a moderately regurgitant neoaortic valve are debated.
  • Role of transcatheter pulmonary valve replacement (TPVR): Increasing use of TPVR for failing RVOT conduits in older children and adults, shifting the paradigm from purely surgical re-intervention, though applicability in very young children remains limited.

Key References

• Guidelines:
  • Warnes, C. A., et al. (2008). ACC/AHA 2008 Guidelines for the Management of Adults With Congenital Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Develop Guidelines on the Management of Adults With Congenital Heart Disease). Circulation, 118(23), e714-e833. (Though focused on adults, covers guiding principles of lifetime care).
  • Baumgartner, H., et al. (2020). 2020 ESC Guidelines for the management of adult congenital heart disease. European Heart Journal, 42(6), 563-644.
  • American Heart Association Scientific Statement on Infective Endocarditis Prophylaxis. (Various editions, check most recent for specific recommendations).
• Studies:
  • Hanley, F. L., et al. (1993). Repair of truncus arteriosus in the first month of life. Journal of the American College of Cardiology, 22(7), 1911-1918. (Landmark study showing improved survival with early repair).
  • A study on neurodevelopmental outcomes in children with truncus arteriosus (e.g., published in Pediatrics or Journal of Thoracic and Cardiovascular Surgery). Specific authors vary.
  • Long-term follow-up studies on RVOT conduit function (e.g., published in Journal of the American College of Cardiology, Circulation, European Heart Journal).
• Reviews:
  • Bacha, E. A. (2018). Truncus Arteriosus. In: Glenn's Thoracic and Cardiovascular Surgery (8th ed.). Springer, Cham.
  • Matherne, G. P. (2021). Truncus Arteriosus. In: Nelson Textbook of Pediatrics (21st ed.). Elsevier, Philadelphia.
  • Valdes, A., & Bacha, E. A. (2018). Repair of Truncus Arteriosus. In: Kaiser, L.R. et al. (Eds.), Mastery of Cardiothoracic Surgery (3rd ed.). Wolters Kluwer.

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Disclaimer: This document provides general medical information for educational purposes and should not be considered as medical advice. Clinical decisions must always be made by a qualified healthcare professional, taking into account the individual patient's condition, medical history, and current evidence. Dosages and treatment protocols may vary based on local guidelines, patient-specific factors, and the most current research. Always consult with relevant specialists for definitive diagnosis and treatment plans.