Case

A 31-year-old G5P3T1 woman was referred for foetal echocardiography for the suspected cardiac anomaly. She had well-controlled hypertension and hypothyroidism. There was no family history of congenital heart disease. A 19-week foetal echocardiogram demonstrated dextrocardia, and an unbalanced atrioventricular septal defect with a dominant right-sided left ventricle. Both outlets arose from the single ventricle, with the aorta anterior to a smaller pulmonary artery. Severe sub-pulmonary stenosis and regurgitation were seen. Branch pulmonary arteries were confluent and hypoplastic. Inferior caval vein drained to the left-sided atrium while bilateral superior caval vein drained to their ipsilateral atrium. Pulmonary veins drained unobstructed through a confluence to the right-sided atrium. Ductus arteriosus was absent and two aorto-pulmonary collaterals from the thoracic aorta were identified (Fig 1, Supplementary videos 1 and 2). Ventricular function was normal and there was no atrioventricular valve regurgitation. The stomach was seen centrally and leftward, the liver was midline and there was asplenia; findings were in keeping with a right atrial isomerism. The patient was counselled about management. The challenge of small branch pulmonary arteries and collateral vessels in combination with anomalous pulmonary venous drainage and risk of pulmonary vein stenosis was reviewed. Pregnancy was continued and genetic testing declined. She was reassessed at 22-, 29-, and 36-weeks’ gestation.

Figure 1.

Foetal echocardiogram at 29 weeks and 2 days’ gestation: ( a ) Four-chamber view showing single atrioventricular valve connection to a right-sided dominant left ventricle. A moderator band was not seen. A rudimentary right ventricle is seen leftward of the morphologic left ventricle. Pulmonary venous confluence was seen behind the larger right-sided atrium. ( b ) Sagittal imaging showing aortic arch with two large collaterals coursing towards the lungs. ( c and d ) Sagittal imaging showing larger and anterior aortic valve and posterior and smaller pulmonary valves with pulmonary regurgitation seen on colour Doppler. A = anterior; Ao = aorta; C = pulmonary venous confluence; L = left; LV = left ventricle; R = right; RV = right ventricle; P = posterior; Pu = pulmonary outflow; * = aorto-pulmonary collaterals.

A term, 2.86 kg female neonate was born by caesarean section. Oxygen saturation ranged between 88 and 92% in room air. A postnatal echocardiogram confirmed prenatal diagnosis (Fig 2, Supplementary video 2). The abdominal ultrasound showed asplenia and midline liver without bowel malrotation. Chest computed tomography showed bilateral right bronchi (Fig 2). Ultrasound and computed tomography, in combination with an echocardiogram, confirmed right atrial isomerism. Genetic testing postnatally was declined. On day 3, she developed a bowel perforation and required partial colectomy and loop ileostomy. At 2 months, cardiac catheterization showed dual pulmonary perfusion by aorto-pulmonary collaterals and central pulmonary arteries (Fig 2, Supplementary videos 3 and 4). She underwent pulmonary outflow stenting and coil occlusion of collaterals. Pulmonary veins were not assessed. She developed respiratory distress from pulmonary vein stenosis. At 3 months, she received a 3.5-mm right Blaloch–Taussig shunt, stent removal, and suture-less pulmonary vein repair. She required extracorporeal membrane oxygenation and a delayed chest closure. Ongoing desaturation prompted repeat cardiac cross-sectional imaging; complete obstruction of the left upper pulmonary vein, severe stenosis of the right upper pulmonary vein, moderate stenosis of the right lower pulmonary vein, and minimal stenosis of the left lower pulmonary vein were found. She was deemed unsuitable for heart–lung transplantation. Given limited options, comfort care was initiated at 4 months and the patient demised.

Figure 2.

Postnatal imaging confirming prenatal findings: ( a ) Postnatal two-dimensional echocardiogram in short axis showing a dominant, left ventricle that is rightward. A rudimentary right ventricle is seen leftward and anterior to the morphologic left ventricle. ( b ) CT chest showing symmetric bronchi in keeping with right atrial isomerism. ( c ) Angiogram showing one aorto-pulmonary collateral vessel arising from the aorta. ( d ) Angiogram showing a second aorto-pulmonary collateral arising from the aorta. A = anterior; L = left; LV = left ventricle; P = posterior; R = right; RV = right ventricle; * = aorto-pulmonary collateral.