Double Aortic Arch: A Comparison of Fetal CMR, Postnatal CT and Surgical Findings.

BACKGROUND: In double aortic arch (DAA) one of the arches can demonstrate atretic portions postnatally, leading to diagnostic uncertainty due to overlap with isolated right aortic arch (RAA) variants. The main objective of this study is to demonstrate the morphological evolution of different DAA phenotypes from prenatal to postnatal life using 3D fetal cardiac magnetic resonance imaging (CMR) and postnatal CT/CMR imaging. METHODS: 3D fetal CMR was undertaken in fetuses with suspected DAA over a six-year period (Jan 2016 - Jan 2022). All cases with surgical confirmation of DAA were retrospectively studied and morphology on fetal CMR was compared to postnatal CT/CMR and surgical findings. RESULTS: 32 fetuses with surgically confirmed DAA underwent fetal CMR. All demonstrated a complete DAA with left-sided arterial duct. The RAA was dominant in 30/32 (94%). Postnatal CT/CMR was undertaken at median age of 3.3months (IQR 2.0-3.9) demonstrating DAA with patency of both arches in 9/32 (28%), with 6 showing signs of coarctation of the left aortic arch (LAA). The LAA isthmus was not present on CT/CMR in 22/32(69%), the transverse arch between left carotid and left subclavian artery was not present in 1 case. CONCLUSIONS: Fetal CMR provides novel insights into perinatal evolution of DAA. The smaller LAA can develop coarctation or atresia related to postnatal constriction of the arterial duct, making diagnosis of DAA challenging with contrast-enhanced CT/CMR. This highlights the potentially important role for prenatal 3D vascular imaging and might improve intepretation of postnatal imaging.

Cardiac manifestations of inherited metabolic disease in children.

Inborn errors of metabolism (IEM) are responsible for around 5% of all cases of cardiomyopathy (CM) and for 15% of non-idiopathic cases. Storage disorders such as Pompe disease (glycogen storage disease type II) typically cause hypertrophic CM, whereas the accumulation of toxic metabolites, as seen in the organic acidurias, is associated with dilated cardiomyopathy (DCM). Mixed pathology is also possible, particularly in late presentations. IEM such as Barth syndrome, a disorder of cardiolipin stability usually associated with DCM, have been associated with rarer types of CM such as endocardial fibroelastosis and left ventricular non-compaction. Conduction disturbances can also occur, particularly in disorders of glycogen metabolism associated with PRKAG2 mutations. Cardiac screening of patients with metabolic diseases is important to guide treatment and stratify risk. Supportive cardiac treatment may be required, and although associated myocardial disease may improve or even resolve with correction of the underlying metabolic disturbance, progression to cardiac transplantation has been described. In this article we document all IEM known to be associated with cardiac disease in children, focusing on common and clinically important diagnoses. We also discuss the pathophysiology of the various types of CM, and present a recommended approach to screening in the pediatric population.