Persistence of the fetal circulation: radiologic considerations

Area of Science:

• Neonatology
• Pediatric Cardiology
• Pulmonary Hypertension

Background:

• Persistent fetal circulation (PFC) is a recognized cause of severe cyanosis in term newborns.
• Elevated pulmonary vascular resistance (PVR) leads to right-to-left shunts via fetal channels.
• Hypoxia, acidosis, and hyperviscosity can stimulate increased PVR.

Purpose of the Study:

• To describe the clinical presentation, diagnostic findings, and management of persistent fetal circulation.
• To differentiate PFC from cyanotic congenital heart disease in neonates.

Main Methods:

• Review of clinical data, chest radiographs, and angiocardiography in term infants with severe cyanosis.
• Assessment of intracardiac anatomy, great vessel relationships, and shunting patterns.
• Evaluation of cardiac chamber size and function, including tricuspid regurgitation.

Main Results:

• Chest radiographs show clear lungs and variable pulmonary vascularity/cardiac size.
• Angiocardiography reveals normal intracardiac anatomy but right-to-left shunting through patent foramen ovale and patent ductus arteriosus.
• Some infants exhibit tricuspid regurgitation and right ventricular dilatation; left ventricle remains normal.

Conclusions:

• Persistent fetal circulation is a treatable cause of neonatal cyanosis.
• Early diagnosis and intensive care, including oxygen and acidosis correction, improve survival rates.
• Vasodilators like tolazoline may be beneficial in managing PFC.