Progress in Pediatric Cardiology 55 (2019) 101149

Accepted 11 September 2019

1058-9813/ © 2019 Elsevier B.V.


Determining situs by abdominal aorta and inferior vena caval findings: It is neither complicated nor ambiguus



William N. Evans, Ruben J. Acherman, Humberto Restrepo



Corresponding authors at: Children's Heart Center Nevada, 3006 S. Maryland Pkwy, Ste. 690, Las Vegas, NV 89109, USA.

E-mail addresses: (W.N. Evans), (H. Restrepo).



We reviewed our center's experience with isomeric situs for those identified prenatally or born between 2003 and 2018. We defined left isomerism as an absent

hepatic portion of the inferior vena cava with azygos/hemiazygos venous return to the superior vena cava. We defined right isomerism as an ipsilateral abdominal

inferior vena cava and aorta. For the period 2003 to 2018, we identified 101 patients that met criteria. Of the 101, 70 (69%) had left isomerism, and 31 (31%) had

right isomerism. Of the 101 patients, 89 were live born. For those with left isomerism, 24/70 (34%) had functionally univentricular hearts versus 30/31 (97%) with

right isomerism (p=0.00001). Overall mortality for live-born patients was higher for right isomerism 42% versus 13% for left isomerism (p=0.029). For the period

2014–2018, 27/27 (100%) of patients with isomerism were diagnosed prenatally compared to 29/57 (51%) for the period 2003–2013 (p=0.0003). In conclusion,

left or right isomerism can be determined by ultrasound imaging of the abdominal aorta and inferior vena caval relationships. To date, all patients have had a

discernable situs without any deemed uncertain. Further, our current prenatal diagnosis of isomerism stands at 100%.


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