AVMs are abnormal collections of blood vessels with direct arterial to venous connections and no normal intervening capillary circulation. They are typically high-flow, low-resistance. They are believed to be congenital and commonly present in adulthood as hemorrhage or new-onset seizures.
Treatment may be a multi-step process, including a combination of surgical intervention/resection, Gamma knife radiation, and intravascular embolization. Embolization is often used prior to surgery to help minimize the complexity of the surgery and associated bleeding risks. The goal of embolization is to decrease the size and shunt burden of the AVM prior to surgical resection. However, in selected cases, embolization alone may be the definitive treatment.
Anesthetic management during the procedure is if often variable, as some centers prefer an awake patient for thorough clinical evaluation prior to embolization. Other centers prefer general anesthesia for optimal imaging, control of respiratory and hemodynamic profile, and to minimize patient movement. Anesthetic considerations for AVM embolization and surgery must take into account the possibility of extensive blood loss. Large-bore IV access and arterial line monitoring are necessary for these procedures. If there is large concern for vascular leak or rupture, blood responses to laryngoscopy and intubation should be blunted. Patient with elevated ICP should be hyperventilated to decrease ICP and enhance quality of angiogram. Prompt awakening at the end of the procedure is helpful to better perform neurological evaluation of the patient. Blood pressure control may still be necessary during emergence.