Risk factors for hemorrhage of brain arteriovenous malformation

Abstract

Patients with brain arteriovenous malformation (bAVM) are at risk of intracranial hemorrhage (ICH). Overall, bAVM accounts for 25% of hemorrhagic strokes in adults <50 years of age. The treatment of unruptured bAVMs has become controversial, because the natural history of these patients may be less morbid than invasive therapies. Available treatments include observation, surgical resection, endovascular embolization, stereotactic radiosurgery, or combination thereof. Knowing the risk factors for bAVM hemorrhage is crucial for selecting appropriate therapeutic strategies. In this review, we discussed several biological risk factors, which may contribute to bAVM hemorrhage.

Keywords: brain arteriovenous malformation; hemodynamic; intracranial hemorrhage; vascular endothelial growth factor; vascular integrity.

Figure 1

The risk factors for brain AVM hemorrhage. Brain AVMs have increased level of VEGF, reduced mural cell coverage, and altered hemodynamics. All of these increase the risk of brain AVM hemorrhage. Alteration in hemodynamics including high flow, increased wall shear stress, and VH can also induce inflammation, BBB leakage, and elevation of VEGF levels, which further increases the risk of hemorrhage. Thalidomide and lenalidomide treatment increase EC PDGFB production and pericyte recruitment. Overexpression of Pdgfb could be another therapeutic strategy to improve BBB integrity. Bevacizumab treatment and intravenous injection of AAV‐sFLT1 vectors that express the extracellular domain of VEGF receptor 1 blocks excess VEGF and inhibits the bAVM formation and progression