ENDOVASCULAR TREATMENT OF EXPERIMENTAL ANEURYSMS WITH LIQUID POLYMERS- THE PROTECTIVE POTENTIAL OF STENTS

LIQUID POLYMERS HAVE previously been used to treat experimental and hu man aneurysms. However, the delivery of a liquid embolic material into the cerebral circulation involves a high risk of irreversible vessel occlusion and stroke. To evaluate methods for the safe and effective t reatment of experimental aneurysms with liquid polymer injection, we t ested four different techniques to deliver cellulose acetate polymer ( CAP) or N-hexyl-cyanoacrylate into canine side-wall carotid artery ane urysms. The animals were observed for 1 to 10 weeks after treatment. T wo aneurysms were treated without protection of the distal circulation , one with CAP and another with N-hexyl-cyanoacrylate. In four cases, an angioplasty balloon was inflated within the parent artery during en dosaccular injection of CAP. In two of these cases, the balloon was pl aced adjacent to the aneurysm orifice, resulting in simultaneous occlu sion of both the aneurysm and the parent artery, and in the other two cases, the balloon was positioned proximal to the aneurysm, resulting in temporary flow arrest. Three aneurysms were treated with either CAP or N-hexyl-cyanoacrylate after implantation of a balloon-expandable t antalum stent within the parent artery across the aneurysm orifice. Co mplete angiographic obliteration was achieved in all but one case. One aneurysm ruptured. Another partially occluded aneurysm reopened 10 we eks after treatment. In all cases treated without stents, distal migra tion of the polymer resulted in either stenosis or occlusion of the pa rent arteries. The combination of stent implantation and polymer injec tion resulted in permanent aneurysm occlusion without detectable polym er migration. An intravascular stent deployed within the parent artery across the aneurysm orifice acted as a safety net during endosaccular polymer injection by allowing blood to flow from the aneurysm cavity while preventing distal migration of liquid polymer.