Vein of Galen Aneurysmal Malformation

Vein of Galen aneurysmal malformation is a rare congenital arteriovenous shunt into the median prosencephalic vein, an embryonic precursor of the vein of Galen. It makes up about 30% of paediatric vascular malformations and is the commonest cause of high output heart failure from a cerebral lesion in neonates.

Pathophysiology. High flow shunting overloads the right heart, causes pulmonary hypertension, and steals blood from the brain. Venous hypertension impairs cerebrospinal fluid absorption and brain perfusion, with progressive white matter injury ("melting brain").

Neonates present with heart failure, cyanosis and pulmonary hypertension, cranial bruit and multi-organ failure. Infants present with hydrocephalus, macrocephaly, dilated scalp veins and developmental delay. Older children present with headache, seizures, intracranial haemorrhage or developmental regression.

Red flags.

• Neonatal heart failure unresponsive to medical treatment.
• Rapid head growth or seizures.
• Intracranial haemorrhage.

Foetal ultrasound and MRI make the diagnosis from about 30 weeks. Postnatal cranial ultrasound with Doppler, MRI and MR angiography define the lesion and brain injury. Echocardiography assesses cardiac function and pulmonary pressure. Catheter angiography is reserved for treatment.

Differential diagnosis.

• Other arteriovenous shunts and pial fistulas.
• Vein of Galen varix, dural sinus malformation.
• Arachnoid cyst and pineal region mass.

Endovascular embolisation (transarterial, liquid embolic agent) is the treatment of choice. Timing depends on cardiac status:

• Neonates with refractory cardiac failure need urgent embolisation to allow cardiac stabilisation, even when staged.
• Stable infants undergo staged embolisation at 4 to 6 months of age, when the brain and vasculature are larger.

Cardiac support. Diuretics, inotropes (dobutamine 5 to 10 microgram/kg/min), ventilation and prostaglandin avoidance, with specialist neonatal cardiology.

Hydrocephalus. Avoid early shunting because of the risk of haemorrhage. Treat after shunt flow is reduced.

Seizures and development. Antiseizure drugs and early developmental support.

Prognosis. Neonates presenting with heart failure have the worst outcome. Outcomes are favourable in more than 60% of those treated in infancy.

Monitoring. MRI and development until school age.

Referral and escalation. Refer urgently to specialist paediatric neurointerventional centres, ideally antenatally.