Disease Description (Causes and Symptoms)
- Disease name: Persistent truncus arteriosus — the medically accepted name.
- Definition/Pathophysiology: During early development, the aorta and pulmonary artery fail to separate, leaving a single common arterial trunk (truncus), and this is almost always accompanied by a ventricular septal defect (VSD). A single common valve (the truncal valve) is present, and the ascending aorta, main pulmonary artery, and coronary arteries arise from a common origin. As a result, blood from the left and right ventricles mixes, causing excessive pulmonary blood flow and heart failure, or it may progress to increased pulmonary vascular resistance. Truncal valve regurgitation (25–50%) or stenosis may occur. A variant in which one pulmonary artery is absent also exists.
- Causes: The cause is unknown in most cases. Genetic factors (e.g., association with 22q11 deletion/DiGeorge syndrome), Down syndrome, fetal rubella infection, and drug exposure during pregnancy (such as anticonvulsants) have been reported as risk factors.
- Main symptoms: Cyanosis in the neonatal/infant period, respiratory distress (rapid breathing, chest retractions), feeding difficulty and poor weight gain, low urine output (a sign of dehydration/heart failure), heart murmur, and lethargy (floppiness). Without treatment, the risk of early death from heart failure, pneumonia, and other conditions during infancy is generally high (a high mortality rate before 1–2 years of age).
- Prevalence: A relatively rare congenital heart defect (approximately 0.034–0.21 cases per 1,000 live births, about 1% of congenital heart disease).
Treatment Methods (Standard Treatment, Medications, Procedures/Surgery, Lifestyle Management, and Precautions)
- Standard treatment: Complete surgical repair is the standard treatment. Performing it as early as possible (usually recommended at around 1–2 months of age, and no later than 3 months; before 6 months depending on the situation) is favorable for the prognosis.
- Complete repair (generally using a Rastelli-type technique): The common arterial trunk is separated, the origins of the aorta and pulmonary artery are separated with a patch, and the VSD is closed in alignment with the pulmonary artery so that aortic blood flows from the left ventricle. A prosthetic conduit containing a valve or a homograft is inserted to connect the right ventricle and pulmonary artery. Truncal valve repair (or replacement) is performed if necessary.
- Partial/bridging surgery: When complete repair is not immediately possible, pulmonary artery banding may be performed to temporarily narrow the pulmonary artery and reduce excessive pulmonary blood flow, with reoperation planned after the child has grown.
- Preoperative/conservative treatment: When heart failure is present, symptoms are controlled with diuretics, oxygen therapy, inotropes, and other measures before surgery. Infections such as pneumonia are treated concurrently.
- Postoperative management and long-term follow-up: The right ventricle–pulmonary artery conduit or homograft may develop size mismatch, calcification, regurgitation, or stenosis as the child grows → reoperation or transcatheter reintervention may be required. Lifelong periodic echocardiography, electrocardiography, and clinical follow-up are recommended, with linkage to an adult congenital heart disease center.
- Precautions and risk of complications: The risk of endocarditis is increased (prevention of infectious diseases and good oral hygiene are important). If pulmonary hypertension and an Eisenmenger reaction (pulmonary vascular obstruction) develop, the course may remain complicated even after surgical correction. If surgery is delayed, increased pulmonary vascular resistance may make complete repair impossible. Complications related to surgery, anesthesia, and reoperation, such as bleeding, infection, and worsening heart failure, may occur.
- Preventive recommendations: Regular follow-up with a pediatric cardiologist; when necessary, genetic (chromosomal) testing and evaluation for associated abnormalities such as aortic arch abnormalities and DiGeorge syndrome.
Checklist Before an Outpatient Visit (Items to Prepare and Information to Provide During the Visit)
- Items to prepare/bring:
- List of current medications (including doses and administration times)
- Previous test results (echocardiography, chest X-ray, electrocardiography, CT/MRI, genetic test results, etc.) and surgical records, if available
- Growth chart (weight and height trends), and records of feeding volume, urine output, and frequency of cyanosis
- Recent respiratory symptoms (cough and fever), hospitalization history, allergies, and immune status (e.g., vaccination status)
- Family history (congenital heart disease or genetic disorders)
- Records of symptom changes (including examples of useful questions to ask during the visit):
- Has apnea, respiratory distress, or fatigue during feeding increased?
- Have there been times when the usual discoloration (cyanosis) became more severe?
- Has daily urine output or activity level decreased?
- Is breathing faster than usual, or is there chest retraction?
- Has there been a recent hospitalization for pneumonia or an infection?
Examples of General Questions to Ask the Doctor
- What is the usual prognosis for this condition? (Including expected survival and quality of life after surgery)
- Is surgery needed immediately? What is the timing of surgery, and why?
- What are the major risks and complications of surgery? How likely is reoperation?
- What are the side effects of the medications currently being taken, and when should they be stopped or adjusted?
- Are special infection-prevention measures, such as endocarditis prevention, needed? (For example, antibiotics for dental treatment)
- What tests will be needed long term, and how often? What will the follow-up plan be during adulthood?
Examples of Condition-Specific Questions
- Our child has regurgitation (or stenosis) of the truncal valve. Please explain whether valve repair (or valve replacement) is needed and how the valve will be managed during surgery.
- Is complete repair possible in the current condition, or is a bridging procedure such as pulmonary artery banding needed first? Please explain the advantages and disadvantages of each option and the expected timing of reoperation (e.g., the replacement interval for the conduit).
- (Optional) Is testing for 22q11 (or other chromosomal abnormalities) recommended, and how would the test results affect treatment and follow-up?