**1.2 Pathophysiology**

AVMs are considered as a major cause of intracerebral hemorrhage, particularly in the young population (33.5% for age<20years) [19]. From a fluid mechanics perspective, arterioles constitute the main flow resistance/drop of the vascular tree (**Figure 3**, OpenStax CNX) via a mechanism of rapid increase of surface contact between the blood and the endothelial surface and thus shear stress induction. Lack of arterioles causes minor pressure drops across the nidus. The mean arterial blood pressure difference between normal and AVM cases is ~40 mmHg

**Figure 2.**

*AVM nidus. Physical location (left), angiogram (center), and pre-surgical anatomy (right) [9].*

**Figure 3.** *Pressure drop along the vascular tree.*

and has become an indicator for potential hemorrhages [20]. These findings are confirmed by modern 4D flow magnetic resonance imaging (MRI) and highresolution magnetic resonance angiography (HR 3D MRA) [21, 22]. The CNS vascular network is not equipped to endure pressure drops exceeding 10 mmHg, particularly not the structurally thin veins. Thus, the biomechanical aspects of AVM pressures, flows, and shear stresses play a major part in the structural failure of its vessels' vascular walls.
