Introduction

Truncus arteriosus is a Latin word in which truncus means "trunk" or "stem”, while arteriosus refers to "artery" or "arterial. Overall, "Truncus Arteriosus" means "arterial trunk" or "arterial stem."

Truncus arteriosus is known as a defective valve due to the malfunctioning of the valve of the heart of a fetus, in which the valve remains open after birth, resulting in congenital disorders named truncus arteriosus.¹

It is a medical condition affecting heart functioning in terms of blood pumping and circulation is impaired due to the possibility of intermixing of oxygenated and deoxygenated blood due to an open valve in the heart.IT is considered a fatal and concerning condition that may affect the quality of life of an individual as it targets the basic functioning of the heart and circulatory system.¹

Prevalence of truncus arteriosus

As it is a congenital disorder in most cases, it is highly prevalent in newborn individuals. According to statistics, about 0.05 to 0.1 per 1,000 live births (or about 1 in 10,000 to 20,000 births) are affected by truncus arteriosus TA, showing a low ratio of neonates suffering from truncus arteriosus TA. At the same time, it is considered a highly complex condition so this low prevalence probability is still concerning due to a life-threatening complication. The provided incidence may be highlighting a respective location; it may vary based on specific location, as it is dependent on various factors.

Risk factors for truncus arteriosus

Truncus arteriosus is still highly prevalent in developing countries due to listed concerning factors such as: 

Genetic factors

Genetic factors include genes that are the causative agents due to impaired gene expression. This may occur due to the following complications:

• DiGeorge Syndrome (22q11.2 Deletion Syndrome)
• Other Chromosomal Aberrations 
• Genetic Mutations
• Inherited Syndromes
• Environmental-Genetic Interactions
• Rare Genetic Conditions

Environmental factors

It covers many factors like maternal diet, maternal health conditions, teratogen exposure, alcohol consumption, smoking, gestational diabetes, medications induced complications targeting heart functioning, impaired folate production, and obesity are highlighting concerns related to environmental factors that are modifiable risk factors which need proper consideration and management.

Demographic factors

It includes some non-modifiable risk factors such as age, ethnicity, race, socioeconomic status, parity and geographical location, making it a more concerning complication in terms of factors that can be changed and managed, but education could help in some regard.

Family history

While considering other factors, one of most prominent and undeniable factor is family history of having congenital heart complications increasing risks for truncus arteriosus, autosomal or recessive patterns of gene inheritance is concerning that is one of most common cause in developing countries like pakistan due to high proportion of cousin marriages and no screening before marriage. Genetic counselling can be a promising motive in terms of lowering the incidence rate of truncus arteriosus, which can be done by a community pharmacist and other healthcare professionals.

Associations with other congenital anomalies

Truncus arteriosus is a congenital disorder which can be interrelated to other congenital disorders that increase the risks of TA in neonates, which may include:

• Vertebral, Anal, Cardiac, Tracheal, Esophageal, Renal, and Limb defects
• Coloboma, Heart defects, Atresia choanae, Retarded growth, Genital anomalies, & Ear abnormalities abbreviated as CHARGE syndrome
• Craniofacial Anomalies like cleft lip/palate, facial dysmorphism
• Renal malformations are commonly seen alongside TA
• Limb abnormalities in association with certain syndromes, like Holt-Oram syndrome

Pathophysiology and clinical manifestation

In case of truncus arteriosus individual has single large artery rather than two separate blood vessels for atrial and venous blood circulation, resulting in mixture formation inside lungs that impaired overall heart functioning because this mixture results in loss of atrial and venous blood differentiation that is one of highlighting component of circulatory system acting as crucial part for proper working of human body. It may result in hypoxia that may increase stress on the cells and on the lungs due to high blood flow, making it difficult for the heart to pump properly, increasing muscle activity that may make heart muscles weaker in the long run.²

Diagnostic methods

As various factors and pathophysiological factors are causative components for truncus arteriosus TA, for which we need a wide and comprehensive diagnostic procedure for timely and accurate analysis, which includes:²

• Electrocardiogram ECG
• Pulse oximetry
• Chest X-ray
• Echocardiogram
• Catheterisation of the heart
• Genetic testing

Trends and patterns in epidemiology

Truncus arteriosus TA incidence can be managed by various means, in which trends and patterns in epidemiology are highly concerning, helping to properly diagnose the disorder. It covers the following : 

• Incidence rate changes with respect to time 
• Technological advancement and diagnostic tools in prevalence
• Prenatal screening cross-sectional study 
• Mortality rates and survival rates comparison with respect to time
• Gene therapy and other genetic research are impactful in lowering the incidence
• Early diagnosis protocols and compliance

Conclusion

A highly concerning condition which can be a risk factor of inter related complication or other multiple factors aggravate the condition lowering quality of heart health, if remained undiagnosed on longer run may lead to major complications such as atrial fibrillation or heart failure .in developing countries proper and on time diagnosis is less prevalent due to insufficient education and counselling leads to unbearable consequences..prenatal screening, genetic testing, pre-marriage screening could help in lowering the incidence rate to minimum level that can be managed effectively.

FAQs

What is truncus arteriosus, and what causes it?

Truncus Arteriosus is a congenital heart defect where there is a single large artery instead of two separate ones (the pulmonary artery and the aorta). This results from the improper development of the heart in the fetus, where the valve remains open after birth. It leads to the mixing of oxygenated and deoxygenated blood, impairing the heart’s ability to pump blood effectively.

What are the risk factors for truncus arteriosus?

Truncus Arteriosus is influenced by several genetic, environmental, and demographic factors. Key risk factors include:

• Genetic factors like DiGeorge Syndrome (22q11.2 deletion) and other chromosomal abnormalities
• Environmental factors such as maternal health conditions (e.g., diabetes), teratogen exposure (alcohol, smoking), and poor maternal nutrition
• Family history of congenital heart defects
• Demographic factors such as maternal age, ethnicity, and geographic location

What are the symptoms and clinical manifestations of truncus arteriosus?

Symptoms of Truncus Arteriosus can include:

• Cyanosis (bluish skin due to low oxygen levels)
• Heart murmur
• Difficulty breathing and respiratory distress
• Poor feeding and failure to thrive in newborns
• Growth delays and exercise intolerance in older children. These symptoms are due to impaired oxygenation and circulation caused by the mixing of oxygenated and deoxygenated blood.

How is truncus arteriosus diagnosed?

Diagnosis of Truncus Arteriosus involves a combination of:

• Clinical examination (looking for heart murmurs, cyanosis, etc.)
• Echocardiogram to visualise the heart structure
• Chest X-ray for evaluating the heart size and blood flow
• Electrocardiogram (ECG) to assess heart rhythms
• Genetic testing to identify associated conditions like DiGeorge syndrome
• Cardiac catheterisation for detailed heart pressure and blood flow measurements