THERAPEUTIC EMBOLIZATION OF NEUROVASCULAR LESIONS

Abstract

SUMMARY Interventional neuroradiologic procedures have become the preferred treatment for certain vascular disorders of the central nervous system as a result of the development of new catheters and embolic agents and improved imaging techniques. Whether these procedures are used preoperatively or as definitive treatment, the risk of embolization has decreased with increasing experience, and they compare favorably with the risk of surgery and other treatment modalities. Although devascularizing procedures decrease or eliminate the blood supply to vascular lesions, transluminal angioplasty and thrombolytic therapy increase blood flow to tissues and are effective treatments for symptomatic cerebral vasospasm and iatrogenic cerebral emboli, respectively. Conscious sedation is the preferred anesthetic technique for therapeutic angioembolization because of the ability to perform repeated neurologic assessment. For the uncooperative, obtunded, and pediatric patient, general anesthesia is required for immobilization, control of the airway, and ventilation. Evoked-potential monitoring and preembolization testing with Amytal sodium have decreased the incidence of neurologic complications significantly. Patients with cardiovascular instability and elevated intracranial pressure are at increased risk if controlled hypotension is necessary during embolization. Complications associated with therapeutic embolization can result in stroke, paralysis, or death. An anaphylactic reaction to contrast media can produce airway obstruction and cardiopulmonary compromise. Resuscitation equipment and emergency drugs should always be available. Acute pulmonary embolism may occur if an arterial injection of embolizing material is carried through an AVM to the venous circulation and thence into the lung. Closure of a large AVM may result in acute systemic hypertension and pulmonary edema; this is a common complication of occlusion of a vein of Galen AVM in an infant. Intracranial hemorrhage is another serious complication of neuroembolic procedures. Emergency management includes airway control, hyperventilation and barbiturate administration for elevated intracranial pressure, and maintenance of cardiovascular stability to preserve cerebral perfusion pressure.