Subclassification and Treatment Results of Ethanol Embolotherapy of Type II Arteriovenous Malformations of the Extremity and Body

Purpose: To evaluate the safety and efficacy of ethanol and coil embolization of type II arteriovenous malformation (AVM) according to a new subtype classification. Materials and Methods: Eighty-four type II AVMs in the body or extremity of 79 patients who underwent AVM treatment from 1996 to 2017 were retrospectively subclassified according to the angiographic morphology of the draining vein as type IIa (arterioles shunt to focal segment of single draining vein), type IIb (arterioles shunt to venous sac with multiple draining veins), and type IIc (arterioles shunt along long segment of draining vein). Coil and ethanol embolization of the focal or long segment of the draining vein or the venous sac was performed with direct puncture or transvenous approach according to subtype. Treatment outcomes, number of treatment sessions, and complications were analyzed. Results: AVM cure (ie, complete embolization) rates were 95%, 76%, and 65% in types IIa, IIb, and IIc AVMs, respectively. The cure rate of type IIa AVMs was significantly better than that of type IIc AVMs (P =.015). Median numbers of treatment sessions were 1 in types IIa and IIb AVMs and 2.5 in type IIc AVMs, with a significant difference between type IIc and the other 2 types (P <.05). Minor complications occurred in 20% of patents and major complications occurred in 7%. Conclusions: The cure rate of type IIa AVMs was significantly better than that of type IIc AVMs, which also required significantly more treatment sessions than the other 2 types.