Fetal descending aortic tortuosity with ductal aneurysm

Abstract

Isolated tortuosity of the proximal descending aorta is a rare congenital disorder. Association of this condition with ductus arteriosus aneurysm (DAA) has not been reported in fetal life1. We report a case of a 23-week fetus in which tortuosity of the descending aorta and DAA was diagnosed with the aid of four-dimensional spatiotemporal image correlation (4D-STIC) rendering. A 26-year-old primigravida with singleton pregnancy was referred to our unit for fetal echocardiography due to suspicion of a retrocardiac vascular channel on mid-trimester ultrasound examination. Fetal echocardiography showed isolated tortuosity of the proximal descending aorta without other structural anomalies (Figure 1a and Videoclip S1). 4D-STIC rendering revealed a large DAA and elongated proximal descending thoracic aorta with helical tortuosity consisting of three turns (Figure 1b,c). Ultrasonographic assessment of the fetus focusing specifically on connective-tissue disorders, such as Marfan syndrome, revealed no discrepancy between the long-bone and abdominal-circumference measurements, with normal morphology of the limbs. The length centiles of the long bones were within the normal range. No ocular abnormalities were suspected on any of the prenatal scans. The neonate was delivered normally at term with a birth weight of 2750 g. On physical examination, there were no obvious phenotypic features of connective-tissue disorder. Non-invasive blood-pressure measurements in all four limbs were normal. Postnatal echocardiography confirmed the prenatal findings of isolated tortuosity of the proximal descending aorta and a large DAA. The diagnosis was confirmed by 256-slice computed tomographic (CT) aortogram with three-dimensional reconstruction. The defect was confined to the proximal descending aorta. There was perfect correlation between the images obtained by fetal 4D-STIC rendering and those by postnatal CT (Figures 2 and 3). The patient is being followed up closely for development of coarctation of the aorta. The pathogenetic basis of the unusual aortic malformation in the present case is unclear. Aortopathies can be associated with a host of connective-tissue disorders including Marfan syndrome, Loeys-Dietz syndrome (LDS), vascular Ehlers-Danlos syndrome (EDS), arterial tortuosity syndrome (ATS) and autosomal recessive cutis laxa syndromes (CLS) associated with mutations of the fibulin-4 (FBLN4) and fibulin-5 (FBLN5) genes2, 3. Abnormal redundancy of arteries, especially of the umbilical arteries, has been reported in the recipient twin in twin-to-twin transfusion syndrome4. A cohort of 22 patients from South India presenting in infancy with lethal arteriopathy syndrome owing to FBLN4 mutations has been described previously, however, in this cohort, the syndrome was associated with a typical phenotype and was characterized by a more generalized involvement of the aorta and its branches5. In our patient, the defect was confined to the proximal descending aorta and the ductus arteriosus and we did not observe any of the characteristic phenotypic features associated with the abovementioned connective-tissue disorders. Genetic studies are currently underway, including evaluation of the genes fibrillin-1 (associated with Marfan syndrome), transforming growth factor beta receptor types 1 and 2 (associated with LDS), collagen type III alpha 1 chain (associated with EDS), solute carrier family 2 member 10 (associated with ATS) and FBLN4 and FBLN5 (associated with CLS and FBLN4 mutation-related lethal arteriopathy), using DNA isolated from the peripheral blood leukocytes of the neonate and the parents. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.