Vein of Galen Malformation
Vein of Galen malformation is one of the most common arteriovenous malformations in infants and fetuses. It is a deep, large vein at the base of the brain. A Vein of Galen aneurysm is a type of cerebral vascular malformation that affects the vein and cerebral arteries.
The malformation occurs as a result of lacking capillaries that normally connect arteries to veins, which function to slow blood flow. It causes blood to be rapidly shunted from the cerebral arteries to the cerebral veins, causing an overall increase in blood flow. This makes the heart work harder than normal and can lead to cardiac failure or fetal hydrops.
Vein of Galen malformation can be diagnosed in utero (while still in the womb). Fetal MRI is done to confirm diagnosis and help define the degree of involvement. Serial sonography and echocardiograms are used to monitor fetal well-being. These are done every one to two weeks after diagnosis and are often used to monitor changes in the aneurysm as well as determine the presence of cardiac failure and hydrocephalus, which can be the result of an obstruction of cerebrospinal fluid outflow.
After 32 weeks gestation, biophysical profiles are done biweekly to assess fetal well-being and monitor for fetal hydrops. If deteriorating cardiovascular status is noted, early delivery may be necessary.
No fetal therapy is currently available for this anomaly. After birth, interventional neuroradiological techniques are the method of choice. By feeding a narrow catheter through the arteries that lead to the defect, surgeons can introduce materials that block blood flow through the malformation and form a clot that closes it off.
A pediatric cardiologist should be consulted to follow cardiac output and the management of heart failure. Head circumference measurements should be obtained regularly and monitored carefully to detect hydrocephalus. A ventriculoperitoneal shunt may be required for hydrocephalus in some infants.