What is Truncus Arteriosus

Truncus arteriosus is a rare, life-threatening congenital heart defect where a single large vessel fails to separate into the aorta and pulmonary artery during fetal development, causing oxygen-rich and oxygen-poor blood to mix. This condition requires surgical intervention in the neonatal period to redirect blood flow and allow the heart to function properly. Currently, 105 individuals in the DiseaseMaps community have shared their experiences living with truncus arteriosus.

What exactly happens in the heart during Truncus Arteriosus?

In a healthy heart, the aorta and pulmonary artery are separate structures. In truncus arteriosus, a single common trunk arises from the heart, which supplies blood to the lungs, the coronary arteries, and the rest of the body. Because this common vessel also sits over a large ventricular septal defect (a hole between the lower heart chambers), the heart must work much harder than normal to pump blood, often leading to pulmonary hypertension and heart failure if left untreated.

How is Truncus Arteriosus classified?

The most widely accepted system for classifying truncus arteriosus is the Collett-Edwards classification, which categorizes the defect based on how the pulmonary arteries branch off the common trunk:

• Type I: A short pulmonary trunk arises from the main vessel, which then divides into left and right pulmonary arteries.


• Type II: The left and right pulmonary arteries arise separately but close together from the back of the main trunk.


• Type III: The left and right pulmonary arteries arise independently from the sides of the main trunk.


• Type IV (sometimes reclassified as pulmonary atresia): The pulmonary arteries are absent, and the lungs receive blood through collateral vessels.

Who is affected by Truncus Arteriosus?

Truncus arteriosus is a rare condition, accounting for approximately 1% of all congenital heart defects. It affects both males and females equally and is usually diagnosed shortly after birth due to symptoms like rapid breathing, cyanosis (bluish skin), and poor feeding. While the exact cause is often unknown, it is occasionally associated with genetic conditions such as 22q11.2 deletion syndrome (DiGeorge syndrome).

Next steps

• Consult a pediatric cardiologist immediately for a formal echocardiogram and specialized care plan.


• Connect with the 105 members of the DiseaseMaps truncus arteriosus community to share experiences and find support.


• Discuss genetic testing with a counselor to understand potential underlying chromosomal factors.


• Monitor for signs of heart failure, such as difficulty breathing or failure to gain weight.

Medical disclaimer: This information is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD)


• Orphanet: Portal for rare diseases and orphan drugs


• OMIM (Online Mendelian Inheritance in Man)


• American Heart Association: Congenital Heart Defects