Can truncus arteriosus (a congenital heart defect where a single blood vessel comes out of the heart) cause a boot-shaped heart, characterized by a cardiac malformation?

From the Guidelines

Yes, truncus arteriosus can cause a boot-shaped heart appearance on imaging, as seen in the case of an 18-week fetus with truncus arteriosus, facial dysmorphia, low-set ears, and retromicrognathia, which is highly suggestive of DiGeorge syndrome (22q11.2 deletion syndrome) 1. The boot-shaped heart typically results from right ventricular hypertrophy and is classically associated with Tetralogy of Fallot, but can occur in other conotruncal defects including truncus arteriosus. Truncus arteriosus is a congenital heart defect where a single arterial trunk fails to separate into the aorta and pulmonary artery during embryonic development. This constellation of findings—truncus arteriosus, boot-shaped heart, and craniofacial abnormalities—warrants genetic testing for 22q11.2 deletion, as approximately 35-40% of patients with truncus arteriosus have this genetic abnormality 1. The facial features described are consistent with the characteristic facial phenotype seen in DiGeorge syndrome, which results from abnormal neural crest cell migration affecting both cardiac and craniofacial development. Key points to consider in this case include:

• Truncus arteriosus is a severe complexity congenital heart disease that requires intracardiac repair in infancy, often with staging procedures 1.
• The presence of truncus arteriosus, along with other conotruncal defects, is a common feature of DiGeorge syndrome (22q11.2 deletion syndrome) 1.
• Genetic testing for 22q11.2 deletion is essential in patients with truncus arteriosus, especially those with associated craniofacial abnormalities 1. It is also important to note that truncus arteriosus is classified as a great complexity or complex congenital heart disease, according to the AHA/ACC and ESC guidelines 1. Overall, the finding of a boot-shaped heart with truncus arteriosus in an 18-week fetus, along with facial dysmorphia, strongly suggests a diagnosis of DiGeorge syndrome (22q11.2 deletion syndrome), and warrants further genetic testing and evaluation.

From the Research

Truncus Arteriosus and Boot-Shaped Heart

• Truncus arteriosus is a rare congenital heart defect characterized by a single arterial trunk that supplies systemic, pulmonary, and coronary circulations 2.
• The condition can be associated with various cardiac and extracardiac manifestations, including genetic anomalies such as 22q11 microdeletion 2, 3.
• A boot-shaped heart is often associated with tetralogy of Fallot, but it can also be found in other congenital heart defects, including truncus arteriosus 4.

Fetal Autopsy Findings

• The fetal autopsy of an 18-week-old fetus revealed a boot-shaped heart with truncus arteriosus, facial dysmorphia, low-set ears, and retromicrognathia.
• These findings are consistent with the conotruncal anomaly face syndrome, which is associated with a deletion within 22q11.2 3.
• The presence of truncus arteriosus and other congenital heart defects can be diagnosed prenatally using fetal echocardiography 2, 5.

Management and Outcome

• The management of truncus arteriosus typically involves surgical closure of the ventricular septal defect and placement of a right ventricle to pulmonary artery conduit 6.
• The outcome of truncus arteriosus depends on various factors, including the presence of associated anomalies and the timing of surgical intervention 2.
• Advances in prenatal imaging and early diagnosis have improved the management of truncus arteriosus, allowing for detailed planning of delivery and immediate postnatal care in specialized centers 2.