ABSTRACT
According to the angiographic findings, peripheral arteriovenous malformations (AVMs) can be classified into six different types (type I, type IIa, type IIb, type IIc, type IIIa, and type IIIb), and according to the types, treatment strategy is different. Type I is treated by embolization of the fistula between the artery and vein with coils. Type II (IIa, IIb, and IIc) AVM is treated as follows: first, reduce the blood flow velocity in the venous segment of AVM with coils, and second, perform ethanol embolotherapy of the residual shunts. Type IIIa is treated by transarterial catheterization of the feeding arteries and injection of diluted ethanol. Type IIIb is treated through transarterial or direct puncture approaches. High concentration of ethanol is injected through the transarterial catheter or direct puncture needle. When the fistula is large, coil insertion is required to reduce the amount of ethanol. Type I and type II AVMs showed the best clinical results, and type IIIb also showed an acceptably good response rate. However, either alone or in combination with other types, type IIIa showed the poorest response rate. By using a different treatment strategy according to the types of AVMs, a high clinical success can be achieved.
