Operative Planning

• Magnetic resonance (MR) imaging/MR angiography/MR venography are extremely helpful to determine if cerebral damage has occurred, to evaluate the degree of myelination, to delineate the major arterial supply to the lesion, to evaluate the category of malformation, and to assess for hydrocephalus. It is important to delineate an arteriovenous malformation draining into the true vein of Galen from VGAM, which drains in to the persistent embryonic pros-encephalic vein of Markowski.
  
• Clinical assessment of weight, head circumference, and neurologic status, evaluation of renal and liver function, cardiac ultrasound, cranial ultrasound
  
• The type and timing of intervention is beyond the scope of this text; however, in general, transarterial flow reduction by staged arterial endovascular embolization is recommended to allow for optimal physical and neurologic development. In some cases, a transvenous approach is employed to reduce flow or cure the lesion.

Special Equipment

Anesthetic Issues

• General anesthesia
  
• Often provided by the pediatric neonatal intensive care unit team in neonates with heart failure, preparation for systemic hypotension if required during embolization

Positioning

• The patient is placed in the supine position.
  
• Intravenous antibiotics, if needed, are given.
  
• A Foley catheter is placed.
  
• The proper shielding is placed on the patient.
  
• Both inguinal areas are shaved and prepped with iodine solution.
  
• A sterile drape is placed over the prepped areas.
  
• The head is positioned in neutral position and gently taped in place.

Technique

• Femoral artery puncture is performed with a micropuncture kit, and a 4F sheath is inserted in the right common femoral artery.
  
• Four French diagnostic catheters are used to perform one to three angiographic runs in neonates with great care taken to monitor contrast amount (roughly 6 mL/kg limit).
  
• One vertebral and both common carotids catheterized and angiographic biplane runs performed
  
• Microcatheter navigation under digital roadmap into the dominant arterial feeder through the diagnostic catheter as a guide catheter perfused with heparinized saline
  
• Embolization performed under systemic hypotension if possible because of the high-flow nature of these shunts
  
• Embolization performed with liquid embolic agent of choice. Occasionally preceded by coil embolization or coils alone to slow flow and prevent embolic agent passing prematurely into the draining vein.
  
• Alternate sides for subsequent femoral artery punctures

Sheath Removal

• The sheath is removed and manual compression is applied as described.