Search

Background and Purpose: The relationship between aneurysm dimensions, flow, thrombosis, and rupture remains poorly understood. We attempted to clarify this relationship by exploring various swine aneurysm models., Materials and Methods: Bilateral carotid aneurysms were constructed according to 3 protocols in 24 animals: small aneurysms with wide necks (group 1; n = 6 animals); small aneurysms with small necks (group 2; n = 4 animals), and giant aneurysms with large necks (group 3; n = 14 animals). Group 3 included 3 subgroups, related to testing the model in various experimental conditions: The neck was clipped in 3 animals; venous pouches lacked an endothelial lining in 4 animals; and 7 were control animals. Animals were followed until rupture, or for 1-4 weeks. Angiography was performed postoperatively and before euthanasia. We studied lesion pathology, paying attention to thrombosis, recanalization, wall composition, and perianeurysmal hemorrhage., Results: Groups differed significantly in aneurysm dimensions and aspect ratio (P = .002). Ruptures occurred more frequently in animals with untreated giant aneurysms (7/7) than in animals with small wide-neck (0/6) or small-neck (2/4) aneurysms (P = .002). Ruptures occurred only in animals with thrombosed aneurysms. Lesions lacking an endothelial lining and 5 of 6 clipped venous pouches thrombosed but did not rupture. One giant lesion ruptured despite complete clipping. The wall was deficient in α-actin and was infiltrated with inflammatory cells and erythrocytes in all thrombosed cases, ruptured or not. Ruptures were associated with recanalizing channels in 9 of 10 cases., Conclusions: Thrombosis, inflammation, and recanalization may precipitate aneurysmal ruptures in a swine model.

Background and Purpose: Cyanoacrylates are effective occlusive agents in neurovascular interventions. To study their potential to improve long-term results of endovascular treatment of aneurysms, we conducted experimental studies in canine aneurysm models., Methods: Venous pouch carotid aneurysms were constructed in dogs. Results of coil embolization of lateral wall and bifurcation aneurysms were compared. A lateral wall model of embolization with gelatin sponges was used to study the effects of coating sponges with cyanoacrylate on angiographic results and neointima thickness at 3 and 12 weeks. These models were also used to investigate the control of endovascular cyanoacrylate deposition, alone or over a coil placed at the neck of the treated lesions. The results of endovascular cyanoacrylate embolization of bifurcation aneurysms were compared with those of coil embolization at 3 months., Results: Bifurcation aneurysms treated with coils showed more frequent recurrences (P <.01) and thinner neointimas (P <.01) at 3 months than did lateral wall aneurysms. Cyanoacrylate-coated sponges improved angiographic results (P <.05) and led to thicker neointimas at 3 and 12 weeks (P <.05) as compared with uncoated sponges. Endovascular cyanoacrylate deposition with microcatheters led to stray emboli in all cases. Cyanoacrylate delivery was improved by a single coil positioned at the neck of the aneurysm, but parent vessel embolization still occurred in 25% of the animals. Cyanoacrylate embolization of bifurcation aneurysms improved angiographic results at 3 months as compared with coil embolization (P <.01)., Conclusion: Cyanoacrylate embolization is currently difficult to control. It has the potential to decrease recurrences after endovacular treatment of aneurysms, but a safe method for endovascular delivery has yet to be developed.