From the Guidelines
An arteriovenous malformation (AVM) is a direct connection of artery to vein via abnormal dilated vascular channels without a normal intermediary capillary bed, posing risks of hemorrhage, epilepsy, and other neurological deficits. AVMs are characterized by an abnormal connection between the high-pressure arterial system and the low-pressure venous system, resulting in high-flow shunting of blood 1. The abnormal dilated vascular channels in AVMs are known as the nidus, and the true incidence of brain AVM is unknown, although asymptomatic prevalence on MRI is estimated at 0.05% 1. Some key points about AVMs include:
- They can present with hemorrhage or epilepsy, and the annual rupture risk of a brain AVM is 1.3% for previously unruptured AVM and up to 4.8% for previously ruptured lesions 1
- Imaging findings associated with higher hemorrhage risk include intranidal aneurysm, deep venous drainage, deep location, or venous outflow obstruction 1
- Treatment for AVMs includes surgical resection, endovascular embolization, stereotactic radiosurgery, or medical management, with the ARUBA trial concluding that medical management alone was superior to medical management with interventional therapy for the prevention of death or stroke in patients with unruptured brain AVMs 1 The management and treatment of AVMs should prioritize minimizing the risk of morbidity, mortality, and improving quality of life, taking into consideration the size, location, and the patient's overall health. Regular monitoring through imaging studies is essential for patients with known AVMs to track any changes that might require intervention.
From the Research
Definition of AVM
- Brain arteriovenous malformations (AVMs) are anomalous direct shunts between cerebral arteries and veins that convalesce into a vascular nidus 2.
- AVMs are unusual vascular pathologies characterized by the abnormal aggregation of dilated arteries and veins in the brain parenchyma, with direct connections between the arteries and veins 3.
Characteristics of AVM
- AVMs have a significant cumulative risk for hemorrhage, with intracranial hemorrhage and seizures being the most common presentations 2, 4.
- The absence of a normal vascular structure and capillary bed leads to direct connections between the arteries and veins, making AVMs prone to rupture 3.
Treatment Options for AVM
- Treatment options for AVMs include observation, surgical resection, endovascular embolization, stereotactic radiosurgery, and multimodal treatment 2, 4, 5, 6.
- The selection of treatment depends on AVM features, including size, location, pattern of venous drainage, surgical access, rupture status, and previous treatments 6.
- Curative embolization of AVMs is an attractive concept that has emerged in recent years, with increasing clinical evidence for its safety and efficacy 6.