Embolization of peripheral vascular malformations with ethylene vinyl alcohol copolymer (Onyx)

PURPOSE: To demonstrate the feasibility and preliminary efficacy of endovascular embolization of peripheral congenital vascular malformations (VMs) with use of a nonadhesive liquid embolic agent, Onyx. MATERIALS AND METHODS: Nine patients with a mean age of 20.8 years had local low-flow (n = 4), local high-flow (n = 3), or diffuse high-flow (n = 2) VMs located in the upper or lower extremities. In all patients, endovascular embolization was performed via the superselective catheterization of arterial feeders of VMs with use of microcatheters in a coaxial technique. A total of 15 embolization procedures were performed with Onyx, which was composed of 6%, 8%, or 20% ethylene vinyl alcohol copolymer dissolved in dimethyl sulfoxide. RESULTS: In two of four patients with local low-flow VMs, the lesions were embolized completely. In the other two patients with local low-flow VMs, embolizations were incomplete. The remaining five high-flow lesions of local (n = 3) or diffuse (n = 2) types were also embolized incompletely. In all patients with local low-flow VMs and in one patient with a local high-flow VM, clinical signs and symptoms were resolved significantly. Other patients did show clinical benefit from embolization to varying degrees. CONCLUSION: In our experience in a limited number of cases, Onyx promises and provides important advantages over conventional embolic agents in the endovascular transcatheter embolization of congenital peripheral VMs. However, as with other embolic agents, it is far from perfect.