247 - Vein of Galen Aneurysmal Malformation

Abstract

A vein of Galen aneurysmal malformation (VGAM) is a fistulous arteriovenous malformation (AVM) that is unique in early childhood. It is located in the subarachnoid space in the choroid fissure and is embryologically related to the development of the choroid plexus. Enlargement of the vein of Galen may result from choroidal malformation, mural malformation, vein of Galen aneurysmal dilation caused by a pial AVM or dural arteriovenous fistula (AVF), or a vein of Galen varix. VGAM results from persistence of the median prosencephalic vein that occurs during embryonic stages 6 weeks (21 to 23 mm) and 11 weeks (50 mm). Choroidal VGAMs have multiple fistulas with an interposing arterial network between the feeders and the draining vein. The mural type has a single or a few fistulas on the wall of the draining vein. Clinical manifestations of VGAM are high-output cardiac failure in the neonatal period or symptoms caused by venous hypertension secondary to the hydrodynamic disorder during infancy and childhood. Indications for early intervention include unstable or progressive cardiac failure despite maximal medical treatment, development of significant macrocrania or hydrocephalus, recognition of developmental delay or venous ischemic changes such as calcifications, and pial venous hypertension. Endovascular embolization is the treatment of choice and can lead to favorable clinical outcomes. The immediate treatment goal in the neonate is to alleviate congestive heart failure (CHF) so the patient can tolerate oral feedings and gain weight, and the goal for infants and children is to restore normal hydrovenous equilibrium to permit normal development. The final goal of treatment for VGAM is complete obliteration of the lesion with normal development of the patient without neurological deficits. An improved understanding of the clinical, anatomic, and pathophysiologic features of VGAM and advancement of endovascular embolization as the primary therapy have significantly improved the prognosis for patients with these malformations.