Introduction/purpose Histopathological changes in cerebral arteriovenous malformation (AVM) draining veins secondary to chronically high AVM inflow have not been clearly elucidated. Here, we examine the relationship between draining vein wall thickness and AVM flow rate.
Materials and methods Records of patients with cerebral AVMs evaluated at our institution between 2007–2013 were retrospectively reviewed. Patients were included if a surgical specimen of the nidus was available and if flows were obtained before treatment using quantitative magnetic resonance angiography. Specimens were mounted on slides and stained with hematoxylin and eosin as well as elastin special stain. Perinidal veins were identified and the wall thickness of each vein was measured from digitized images of the slides (Figure 1). Maximum vein wall thickness was recorded for each specimen. Intranidal arteries were also identified and the diameter of each artery was measured. Total AVM flow was estimated as aggregate flow within primary arterial feeders or flow in single draining veins. The relationship between maximum vein wall thickness, total AVM flow, flow per draining vein, flow per unit volume of AVM, and mean intranidal artery diameter was assessed.
Results 28 patients (20 male, 8 female) with mean age of 37 years (range 16–68 years) were included. Spearman’s correlation revealed a statistically significant relationship between maximum vein wall thickness and total AVM flow (rho = +0.51, P = 0.006) (Figure 2) as well as AVM flow per draining vein (rho = +0.41, P = 0.03). However, there was no statistically significant correlation between maximum vein wall thickness and flow per unit volume of AVM (rho = +0.27, P = 0.17) or mean intranidal artery diameter (rho = +0.42, P = 0.24). Mean vein wall thickness was significantly higher in the presence of venous ectasia (562 μm vs. 300 μm, P = 0.007). Presence of venous stenosis was not significantly associated with age, Spetzler-Martin grade, volume, number of draining veins, deep venous drainage, intranidal fistula, or maximum vein wall thickness.
Conclusion Maximum vein wall thickness is significantly related to total AVM flow and AVM flow per draining vein. This finding implicates chronically high AVM inflow in venous intimal hyperplasia and possible subsequent development of venous outflow stenosis.
Disclosures S. Shakur: None. A. Hussein: None. S. Amin-Hanjani: None. T. Valyi-Nagy: None. V. Aletich: None. F. Charbel: None. A. Alaraj: None.
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