Transarterial embolization of cerebral arteriovenous malformations: a durable treatment for venous side hemorrhage?

Cerebral arteriovenous malformations (AVMs) have been occasionally reported to bleed from their venous side. This may particularly be the case when venous ectasias or aneurysms develop in the setting of steno-occlusive venopathy. Venous side hemorrhage should be suspected when the hematoma is centered on the venous pouch or when a venous pseudoaneurysm is identified on angiography. For AVMs with an identifiable point of rupture, early treatment is recommended in an attempt to secure the weak spot and minimize the risk of rerupture. When possible, microsurgical resection is the definitive and preferred treatment. In contrast, because of its latency period, stereotactic radiosurgery does not confer immediate protection in such cases. Endovascular transarterial embolization may offer immediate cure to only a minority of small AVMs, but remains a very useful temporizing strategy for arterial rupture sites such as proximal or intranidal aneurysms, allowing to defer definitive AVM treatment by either microsurgery or radiosurgery to a later stage. However, when the rupture site is venous in location and the AVM cannot be readily cured by either microsurgery because of its location in eloquent brain or embolization because of its large size, protecting patients from early rerupture may become problematic. We propose that, by reducing flow through the AVM, transarterial embolization may lead to secondary thrombosis of venous pseudoaneurysms and confer durable occlusion of these weak spots, pending definitive AVM cure. Therefore, transarterial embolization should be routinely attempted in such difficult-to-manage cases. An illustrative clinical case is presented in support of this hypothesis.