Vein of Galen Malformations (VOGM)

What Is a Vein of Galen Malformation?

The vein of Galen malformation (VOGM) is a rare blood-vessel malformation in the brain that develops before birth (usually during the first trimester) and is sometimes diagnosed in the womb or soon after birth.

The vein itself is a large deep vein at the base of the brain that takes away the oxygen-depleted blood. However, in this malformation, capillaries that normally slow blood flow and permit oxygen exchange with the surrounding tissues are missing, and so blood rushes directly from arteries into veins causing the heart to overwork.

If not diagnosed and treated early, VOGM can lead to a number of problems in infants, including: 

• Heart failure 
• Pulmonary hypertension 
• Hydrocephalus
• Brain injury 

VOGMs belong to the family of disorders called arteriovenous malformations (AVM) and represent the most severe form of AVMs. The condition is sometimes referred to as a vein of Galen aneurysmal malformation (VGAM).

What Causes Vein of Galen Malformations?

The exact causes of VOGMs are not entirely known, a genetic mutation may play a part in this disorder. It is believed that VOGMs are not an inherited genetic trait.

What Are the Signs & Symptoms of Vein of Galen Malformations?

In the more severe cases, the blood overload goes almost directly to the heart and rapidly overwhelms it, leading to congestive heart failure. Depending on the severity of the condition, it may show up in several ways:

• In newborns (typically within the first month) with congestive heart failure (sometimes the condition is noted in ultrasound before birth)
• Infants with abnormally enlarged head and developmental delay (the enlarged head occurs because the malformation blocks the normal flow or absorption of cerebrospinal fluid)
• Older children with a large head and possibly seizures and/or strokes; sometimes learning difficulties are noted

How Is a Vein of Galen Malformation Diagnosed?

A VOGM may be diagnosed in utero through an ultrasound. In most cases, however, a VOGM is diagnosed after birth via magnetic resonance imaging (MRI) and computed tomography (CT). Digital subtraction angiography, a test that uses x-rays and a special dye to see inside the arteries, is another diagnostic method a doctor can use.

How Is a Vein of Galen Malformation Treated?

Embolization is considered the most effective treatment for VOGMs. If a baby or child has been diagnosed with a VOGM, the treating neurointerventional physician will be a board-certified physician who has specific, sub-specialty training in treating high-level vascular abnormalities. A multi-disciplinary team consisting of specialists in Neurology, Cardiology, Neurosurgery and Critical Care is necessary to ensure that all aspects of care for VOGM patients are taken care of, including close follow up of the brain and heart function.

In embolization, the interventional neuroradiologist (neurointerventional surgeon) advances a small plastic tube (catheter) either through the umbilical artery (available during the first week after birth) or the leg artery at the groin, or directly from the carotid artery in certain cases. Catheters can also be inserted from the leg vein (at the level of the groin). The catheters are navigated to the location of the abnormal connection between the arteries and veins, and these abnormal connections are closed using injection of liquid “glue” and sometimes “coils” (miniature “slinkies” made of platinum).