Hemodynamic Characteristics of Cerebral Arteriovenous Malformation Feeder Vessels With and Without Aneurysms.

BACKGROUND AND PURPOSE The pathogenesis of aneurysms associated with cerebral arteriovenous malformation (AVM) feeder vessels is poorly understood. We sought to determine the hemodynamic characteristics of AVM feeder vessels with and without aneurysms. METHODS Patients with AVMs associated with feeder aneurysms who had flow, vessel diameter, and wall shear stress measured before treatment using quantitative magnetic resonance angiography were retrospectively reviewed. Feeders within each AVM were classified into 2 groups based on presence or absence of aneurysms. Hemodynamic parameters were calculated for each arterial feeder and then compared between the 2 groups. RESULTS Eleven patients had AVMs with feeder aneurysms. Of 35 total feeder arteries, 12 had an aneurysm and 23 feeders did not have any aneurysms. Absolute mean flow was higher (510.2 versus 438.4 mL/min; P=0.53) and vessel diameter was lower (4.0 versus 4.8 mm; P=0.24) in feeders with aneurysms but not significantly. However, wall shear stress (96.2 versus 28.0 dynes/cm2; P=0.04) was significantly higher in feeders with aneurysms. CONCLUSIONS Wall shear stress is significantly higher among cerebral AVM feeders harboring aneurysms. Despite similarly high flows, feeder artery diameter tended to be smaller if an aneurysm was present, suggesting that AVM feeders with aneurysms are a subgroup in which vessel remodeling cannot compensate for increased blood flow.