Vein of Galen Aneurysm

A vein of Galen aneurysm is a malformation that occurs in blood vessels inside the brain.

In this condition, arteries carrying oxygen-rich blood to the baby’s brain are abnormally connected directly to a large “deep draining” vein in the brain that returns the blood back to the heart.

The rush of blood returning to the heart forces the heart to work harder, putting the baby at risk of heart failure.

This life-threatening defect occurs during fetal development when the blood vessels in the brain don’t form properly.

A vein of Galen aneurysm is a type of cerebral vascular malformation. It is sometimes referred to by other names, including a vein of Galen malformation (VOGM) or a vein of Galen aneurysmal malformation (VOGAM).

What happens in a vein of Galen aneurysm?

Arteries carry oxygen-rich blood from the heart to the brain. Veins return the oxygen-poor blood back to the heart.

Normally, arteries and veins are connected by capillaries – tiny blood vessels that slow the blood flow and distribute oxygen and nutrients to the surrounding brain tissue.

In a baby with a vein of Galen aneurysm, the capillaries are missing. Oxygen-rich blood flows directly from the arteries into a large, deep draining vein located at the base of the brain.

Without the capillaries to slow down the blood flow, the rush of blood back to the heart increases the pressure in the veins and forces the heart and lungs to work harder than normal. Oxygen delivery to the brain tissue is also reduced.

How will a vein of Galen aneurysm affect my baby?

Complications of a vein of Galen aneurysm may include:

• Heart failure
• Pulmonary hypertension (high blood pressure in the lungs)
• Hydrocephalus (excess fluid in the brain), when increased blood flow prevents the normal absorption of cerebrospinal fluid (CSF)
• Brain injury caused by fluid build-up (creating pressure) in the brain
• Hydrops (fluid accumulation in two or more areas of the fetus’ body, causing severe swelling)
• Neurological impairment
• Bleeding in the brain
• Seizures
• Enlargement of the head

Cause

A vein of Galen aneurysm is a congenital defect, meaning it is present at birth. The cause is typically unknown.

The malformation occurs as the blood vessels are developing in the fetal brain, during the first trimester of pregnancy.

The condition is rare, estimated to occur in 1 out of every 25,000 births.

Diagnosis

A vein of Galen aneurysm may be detected before birth through a routine prenatal ultrasound.

More often it is diagnosed after birth when the baby shows signs of heart failure. Testing at birth may include an angiogram (imaging to examine blood vessels in the brain), a CT (computed tomography) scan, and an MRI.

Signs and Symptoms

Signs and symptoms in a child with a vein of Galen aneurysm may include:

• Enlarged head size
• Prominent or swollen veins in the face or scalp
• Seizures
• Growth problems
• Failure to meet developmental milestones
• Headaches
• Motor impairment

Specialized Prenatal Evaluation and Care

If a vein of Galen aneurysm is diagnosed or suspected during pregnancy, you may be referred to a fetal center for further evaluation and specialized care, ensuring proper treatment.

At Texas Children’s Fetal Center, we arrange for you to visit as quickly as possible for a comprehensive assessment by a team of specialists experienced in diagnosing and treating this rare and challenging condition, including maternal-fetal medicine physicians, fetal imaging experts, pediatric neurosurgeons and neurologists, pediatric interventional neuroradiologists, pediatric cardiologists, and neonatologists.

Additional testing may include: 

• High-resolution anatomy ultrasound to confirm the diagnosis, evaluate the condition and look for other abnormalities
• Ultra-fast MRI for a more detailed view of fetal anatomy
• Fetal echocardiogram to assess fetal heart structure and function
• Doppler ultrasound to examine blood flow patterns
• Genetic testing

Our specialists will then meet with you about the results, provide treatment recommendations, and answer any questions your family has, to help you make the most informed decisions regarding your baby’s care and treatment.

A diagnosis during pregnancy enables your family and your healthcare team to plan ahead for the specialized care your baby will need before, during and after birth, for the best possible outcomes.

Pregnancy and Delivery

Mother and baby will be closely monitored throughout pregnancy with frequent ultrasounds to assess fetal growth and watch for signs of complications, including fetal hydrops (fluid accumulation in multiple areas of the baby’s body) and fetal heart failure, requiring early delivery.

Because newborns with this condition are at risk of heart failure, we recommend delivery at a center with the expertise and resources required to care for the most critically ill newborns, including the highest level neonatal intensive care unit (NICU), avoiding the need for a potentially life-threatening transfer after birth.

Delivery and postnatal care should be carefully planned and coordinated with a team of maternal-fetal medicine specialists, neonatologists, and pediatric specialists experienced in working together to treat babies with a vein of Galen aneurysm.

Our Fetal Center team works closely with specialists from Texas Children’s Cardiology and Pulmonary Medicine departments, both ranked number one in the nation by U.S. News & World Report, and experts from Texas Children’s Vascular Anomalies Center. This means no transfers during critical postnatal periods. It also means that the pediatric specialists responsible for treating your child have been an integral part of their care team since before birth.

Treatment After Birth

Treatment after birth typically involves a minimally invasive procedure known as embolization to repair the vein of Galen aneurysm.

During the procedure, a thin, flexible tube (catheter) is inserted into a blood vessel (often the umbilical artery) and guided into the brain to the site of the aneurysm. Materials such as small metal coils or glue-like substances are then used to close off the abnormal connection, blocking the flow of blood into the large vein and increasing blood supply to the brain.

Treatment may be performed in stages over a period of time, depending on the health of the newborn.  

In some cases, a vein of Galen aneurysm cannot be corrected.

Postnatal Care Team

Depending on the severity of your baby’s condition, his or her postnatal care team may include:

• Neonatologist
• Pediatric neurologist
• Pediatric neurosurgeon
• Pediatric interventional neuroradiologist

Why Texas Children’s Fetal Center?

• A single location for expert maternal, fetal and pediatric care. At Texas Children’s Hospital, you and your baby receive the specialized care required for the diagnosis and treatment of a vein of Galen aneurysm all in one location, including immediate access to our level IV NICU, avoiding the need to transport your critically ill newborn.
• A skilled, experienced team with proven outcomes. We have a dedicated team of maternal-fetal medicine specialists, fetal imaging experts, pediatric neurosurgeons and neurologists, pediatric neurointerventional radiologists, pediatric cardiologists, neonatologists and others who work in concert to care for you and your baby every step of the way, using proven protocols we’ve developed over the years. With their combined expertise and unified approach, this team offers the best possible care for babies with a vein of Galen aneurysm.
• We care for your child’s needs at every stage of life. Our comprehensive approach starts with your first prenatal visit and continues through delivery, postnatal care, and childhood, thanks to one of the nation’s leading teams of fetal and pediatric specialists for the care and treatment of rare birth defects.

Videos

• Texas Children’s Fetal Center: Our care began before he/she was born
• Vascular Anomalies Center at Texas Children’s Hospital