Nonadhesive Liquid Embolic Agent for Cerebral Arteriovenous Malformations: Preliminary Histopathological Studies in Swine Rete Mirabile

Abstract

Embolyx E, an occlusive and nonadhesive embolic agent, is capable of producing permanent occlusion of swine RMB with the development of mild intra- and perivascular inflammatory changes and no clinical complications. The slow endovascular delivery of DMSO produces no untoward angiographic, pathological, or clinical changes. A fast injection of DMSO causes endothelial necrosis and severe inflammatory response in the arterial wall. This embolic material seems to have appropriate biochemical, anatomic, and histopathological characteristics to be used in the treatment of cerebral arteriovenous malformations or vascular cranial base tumors.

Preliminary Experience with Onyx Embolization for the Treatment of Intracranial Dural Arteriovenous Fistulas

“…When this mixture contacts aqueous media, such as blood, DMSO rapidly diffuses away from the mixture, causing in-situ precipitation and solidification of the polymer, with formation of a spongy embolus. 8 This solidification occurs more slowly than that of cyanoacrylates, and since Onyx is nonadherent to the walls of the vessel or microcatheter, this material allows prolonged injection times while decreasing the chances of permanent micro- catheter retention. 8 If proximal microcatheter reflux is observed or unfavorable distal filling occurs, the injection is stopped and resumed after 30 seconds to 2 minutes (refluxhold-reinjection technique).…”

“…8 This solidification occurs more slowly than that of cyanoacrylates, and since Onyx is nonadherent to the walls of the vessel or microcatheter, this material allows prolonged injection times while decreasing the chances of permanent micro- catheter retention. 8 If proximal microcatheter reflux is observed or unfavorable distal filling occurs, the injection is stopped and resumed after 30 seconds to 2 minutes (refluxhold-reinjection technique). 9 Due to its properties and increased predictability, the use of Onyx may allow for more controlled injections with better distal nidus or fistula penetration as compared to cyanoacrylate.…”

“…Histopathologic and angiographic studies have shown no evidence of short-term recanalization after Onyx embolization. 8,10 In addition, Onyx appears to have better surgical handling characteristics than cyanoacrylate. 11 Several series have now established a high degree of safety and efficacy of Onyx in the treatment of intracranial AVMs.…”

“…10 The DMSO angiotoxicity is dependent on the volume injected and time in contact with the endothelium. 8 Murayama et al 8 demonstrated that the injection of 0.3 mL for 40 seconds was safe with no histopathologic evidence of angiotoxicity. Another potential disadvantage of Onyx is the amount of radiation exposure required for prolonged injections.…”

Forcible Intraarterial Injection of a Nonadhesive Liquid Embolic Agent under Microballoon Occlusion: Experimental Study in Swine Liver

“…However, because dimethyl sulfoxide has shown vascular toxicity when injected rapidly (13), a mixture of ethylene vinyl alcohol copolymer and ethanol (EVAL/ethanol mixture) was developed by Hamada et al and has been used for the embolization of arteriovenous malformations with favorable clinical results (14,15). This EVAL/ethanol mixture has a nonadhesive property and is a completely liquid material that can therefore be injected forcibly through a microcatheter.…”