In Vitro Assessment of EmboGel and UltraGel Radiopaque Hydrogels for the Endovascular Treatment of Aneurysms

Purpose: To describe two hydrogel embolic materials, the alginate-based EmboGel and the polyethylene glycol diacrylate-based UltraGel and examine their use as embolic agents in in vitro models of abdominal aortic aneurysm (AAA) endoleak and saccular aneurysms. Materials and Methods: EmboGel is a mixture of iohexol and alginate, with a calcium chloride solution used to induce polymerization. UltraGel is a mixture of igracure, iohexol, and polyethylene glycol diacrylate and polymerizes in the presence of ultraviolet (UV) light. Modified microcatheter delivery systems were used in both cases to demonstrate use of the hydrogels in fusiform and saccular aneurysm models. Results: Preliminary in vitro results suggest that EmboGel and UltraGel provide effective embolization in fusiform and saccular aneurysm models, respectively. Due to the rapid polymerization of EmboGel, the agent was delivered in a strand-like form. When used in conjunction with a stent in an AAA endoleak model, this form was able to effectively fill the aneurysmal cavity and occlude it from the central blood flow. UltraGel, conversely, was delivered as a liquid and slowly polymerized in the presence of UV light. This system in a saccular aneurysm model was able to form a solid cast inside the aneurysm wall, again showing complete occlusion from the parent flow. Conclusions: Preliminary results indicate these two novel hydrogel applications may prove effective for the treatment of saccular and fusiform aneurysms.