Endovascular Treatment of Cerebral Vascular Malformations

Baik, Min Woo

Abstract

The goals of embolization of arteriovenous malformations(AVMs) is to reduce the size and decrease the anomalous flow of the vascular malformation to reduce the risk of hemorrhage, so that the curative procedures of surgical resection or radiosurgery can be performed with minimal risk. Endovascular cure rate for AVMs is limited to 5% to 10%, and when some symptomatic relief is desired in a surgically inadvisable AVMs, partial embolization can be performed. In the planning of the managements of AVMs, the thorough interpretation of the angioarchitecture of AVMs is mandatory as not only the natural history of AVMs but also the difficulties and risks of embolization is directly related with it. Hemorrhage from the AVMs is usually related to an associated aneurysm, out flow restriction and pure deep venous drainage. And so the intranidal aneurysm should be obliterated firstly. In the presence of fistulous rapid flow in AVM nidus, the risk of venous side embolic occlusion and resulting hemorrhage is increased. Staged procedure is necessary to avoid rapid hemodynamic changes in regions of chronic ischemia surrounding the AVMs, however delay in definitive treatment allows the recruitment of leptomeningial collaterals and deep perforators, and recanalization of previously embolized pedicle. Recanalization of pre-radiosurgery embolization segment can be a cause of incomplete obliteration after radiosurgery. The management of AVMs is best accomplished by the multimodality treatment that is based on the recognition of these benefits and limits of embolization.