Molecular and Genetic Insights into Thoracic Aortic Dilation in Conotruncal Heart Defects

Abstract

Thoracic aortic dilation (AD) has commonly been described in conotruncal defects (CTDs), such as tetralogy of Fallot, double outlet right ventricle and transposition of the great arteries, and truncus arteriosus. Several theories for this have been devised, but fairly recent data indicate that there is likely an underlying histologic abnormality, similar to that seen in Marfan and other connective tissue disease. The majority of aortic dissection in the general population occurs after the age of 45 years, and there have been very few case reports of aortic dissection in CTD. Given advances in cardiac surgery and increasing survival over the past several decades, there has been rising concern that, as patients who have survived surgical correction of these defects age, there may be increased morbidity and mortality due to aortic dissection and aortic regurgitation. This review discusses the most recent developments in research into AD in CTD, including associated genetic mutations.

Congenital heart diseases and cardiovascular abnormalities in 22q11.2 deletion syndrome: From well‐established knowledge to new frontiers

“…The clinical importance of these findings remains to be determined, since so far there has been no report of aortic root dissection. However, these findings may provide novel insight into genetic mechanisms underlying aortic root dilatation (Kay, 2016). …”

Feasibility of Wave Intensity Analysis in Patients With Conotruncal Anomalies Before and After Pregnancy: New Physiological Insights?

“…A longer duration between shunting and complete repair has been found to correlate with AD in repaired ToF ( 3 – 5 ). Other observations that have been associated with larger aortic dimensions in ToF include having a right rather than left aortic arch and male sex ( 5 , 6 ). Recent evidence demonstrates that early ToF repair does not normalize aortic compliance and that abnormal ascending aortic flow patterns based on 4D flow cardiac magnetic resonance (CMR) are prevalent and might affect long-term cardiac performance ( 7 ).…”

“…Pivotal questions are whether these abnormalities are inherent or acquired, whether congenital heart disease plays a causal or facilitating role and whether genetic determinants are important. Recent data suggest that CTA may be associated with a primary problem with aortic histology and should be considered a true aortopathy ( 6 ). Patients with CTA present with impaired distensibility of the aorta ( 6 ).…”

“…Recent data suggest that CTA may be associated with a primary problem with aortic histology and should be considered a true aortopathy ( 6 ). Patients with CTA present with impaired distensibility of the aorta ( 6 ). Interestingly, patients with ToF present with a higher degree of aortic dilation and aorta distensibility than d-TGA patients ( 8 ).…”

Commentary: The role of valve-sparing aortic root surgery in congenital heart disease

“…10 Fewer than 10 case reports of aortic dissection in tetralogy of Fallot have been published, with most patients who dissected having had an absolute ascending aortic diameter above 6 cm. 11 No case of dissection in transposition patients has been published. 11 What is uncertain is why conotruncal defects are at risk for dilation.…”