Vein of Galen aneurysmal malformations

Vein of Galen aneurysmal malformations (VGAM) and Vein of Galen aneurysmal dilations (VGAD) are the most frequent arteriovenous malformations in infants and fetuses. VGAM consist of a tangled mass of dilated vessels supplied by an enlarged artery. The malformation increases greatly in size with age, although the mechanism of the increase is unknown. Dilation of the great cerebral vein of Galen is a secondary result of the force of arterial blood either directly from an artery via an arteriovenous fistula or by way of a tributary vein that receives the blood directly from an artery. There is usually a venous anomaly downstream from the draining vein that, together with the high blood flow into the great cerebral vein of Galen causes its dilation. The right sided cardiac chambers and pulmonary arteries also develop mild to severe dilation. Vein of Galen aneurysmal malformations (VGAM) and Vein of Galen aneurysmal dilations (VGAD) are the most frequent arteriovenous malformations in infants and fetuses. VGAM consist of a tangled mass of dilated vessels supplied by an enlarged artery. The malformation increases greatly in size with age, although the mechanism of the increase is unknown. Dilation of the great cerebral vein of Galen is a secondary result of the force of arterial blood either directly from an artery via an arteriovenous fistula or by way of a tributary vein that receives the blood directly from an artery. There is usually a venous anomaly downstream from the draining vein that, together with the high blood flow into the great cerebral vein of Galen causes its dilation. The right sided cardiac chambers and pulmonary arteries also develop mild to severe dilation. 10% of vein of Galen aneurysmal malformations are associated with deleterious heterozygous mutations of EPHB4 Another study found that 30% of cases were associated with mutations in EPH receptor B4 (EPHB4) gene. Malformations often lead to cardiac failure, cranial bruits (pattern 1), hydrocephaly, and subarachnoid hemorrhage in neonates. The heart failure is due to the size of the arteriovenous shunt that can steal 80% or more of the cardiac output, with large volumes of blood under high pressure returning to the right heart and pulmonary circulation and sinus venosus atrial septal defects. It is also the most common cause of death in such patients. Non-developmental syndromes also directly or indirectly affect the Great Cerebral Vein of Galen, although they are extremely rare. These include superior vena cava syndrome (SVCS), and thrombosis of the lateral sinus, superior sagittal sinus, internal jugular vein, or of the Great Cerebral Vein of Galen itself. Testing for a malformed vein of Galen is indicated when a patient has heart failure which has no obvious cause. Diagnosis is generally achieved by signs such as cranial bruits and symptoms such as expanded facial veins. The vein of Galen can be visualized using ultrasound or Doppler. A malformed Great Cerebral Vein will be noticeably enlarged. Ultrasound is a particularly useful tool for vein of Galen malformations because so many cases occur in infancy and ultrasound can make diagnoses prenatally. Many cases are diagnosed only during autopsy as congestive heart failure occurs very early.