Abstract TP579: Ratio of Arteriovenous Malformation Draining Vein to Adjacent Venous Sinus Diameter is Associated With Increased Risks of Vein Stenosis

Abstract

Introduction: Venous outflow stenosis in cerebral arteriovenous malformation (AVM) remains the main risk factor associated with AVM rupture. The hemodynamic process underlying the development of venous outflow stenosis is poorly understood. Here, we compared the location of stenosis within the draining vein of the AVM in relation to the adjacent venous sinus and explored the hypothesis that the ratio of draining vein to adjacent sinus diameter might predict the development of venous stenosis. Methods: Patient demographic parameters, and cerebral angiograms of 290 patients with supratentorial AVMs seen at our institution between 1997 and 2018 were reviewed. AVM draining vein and adjacent venous sinus diameters, degree of draining vein stenosis, and distance (mm) from the stenotic point of the draining vein to the junction of the adjacent draining sinus were recorded. The correlation between percentage of AVM draining vein stenosis and the ratio of venous sinus to AVM draining vein diameters was analyzed. Results: 247 AVMs in 242 patients with complete angiographic data were included, and a total of 361 draining veins were measured. Venous stenosis was present in 131 draining veins (36.3%). Venous stenosis was observed within 20 mm of the junction to the adjacent major draining sinus in 85% of our sample (Fig 1A). The ratio of draining vein to adjacent sinus diameter correlated positively with the percentage of venous stenosis (P=0.0001, r=0.21; Fig 1B). Conclusion: AVM venous outflow stenosis is observed closer to the adjacent venous sinus junction. The degree of venous stenosis is greater when the ratio of AVM draining vein/adjacent venous sinus diameter approaches or is larger than 1. This may be related to more turbulent flow at the junction of the draining vein and venous sinus, especially in larger draining veins, thus leading to venous stenosis with time. Further studies are needed to explore the pathophysiology of venous stenosis.