Treatment of experimental aneurysms with a new liquid embolic agent and a retrievable stent: proof of concept and feasibility study

Background Occlusion of canine bifurcation and sidewall aneurysms was undertaken with a new liquid embolic agent (PHIL 35) assisted by a high-density partially retrievable stent (FRED) with preservation of the carotid artery. Methods Three dogs were used as acute preparations for development of the technique and two were used for chronic studies lasting 90 days. In one animal we intentionally did not completely fill the aneurysm to determine the long-term results of incomplete treatment. The degree of occlusion, carotid artery compromise, and dislodgement and/or migration of embolic material in treated aneurysms were assessed. Results All aneurysms planned for complete obliteration were totally occluded successfully. By design, we partially occluded one aneurysm. In this aneurysm, angiography performed at 30 days revealed less filling, but at 90 days it had persistent small residual filling. We did not detect any distal embolization during the injection and no angiographic occlusions, change in configuration, or delayed migration of the embolic material were found. In the inspected stent, no foreign material was noted. In four animals we successfully removed the stent with preservation of the integrity of the carotid artery. In the fifth we intentionally left both stents deployed. Conclusions We have developed a new treatment for cerebral aneurysms using a combination of a retrievable stent and a new liquid embolic agent.