Stents are increasingly used in the endovascular treatment of intracranial aneurysms. We studied the effects of stenting and endothelial denudation on aneurysm and branch vessel occlusion.
Methods
Bilateral lingual bifurcation venous pouch aneurysms were created in eight dogs, surgically scraping the aneurysmal endothelial lining on one side. Both arteries were immediately stented using balloon-expandable stents. In four other dogs, a wide-neck carotid bifurcation aneurysm was created, with the vein pouch denuded or not (n = 2 each), followed by immediate stenting. Results were compared using angiography and pathology at 10 days (n = 2), 10 (n = 8), and 20 weeks (n = 2). Branch occlusion between initial and final angiograms was recorded. Pathological evaluation of aneurysms was studied, with attention to neointima formation at the aneurysm ostium and around branch vessel origins.
Results
All stented and denuded lingual aneurysms were obliterated compared with two of eight lingual aneurysms that were stented alone (P = .007). None of the carotid bifurcation aneurysms became obliterated (0/4), but denuded aneurysms showed partial thrombosis (2/2). Of 68 total stent-covered branches, 5 (7%) were occluded and 17 (27%) had altered angiographic flow.
Conclusions
Stenting led to suboptimal results in the presence of an intact endothelial layer. Endothelial denudation can promote aneurysm occlusion when combined with stenting.
Clinical relevance
Following endovascular treatment, cerebral aneurysms are prone to recurrences. Stents are increasingly deployed as part of the treatment of intracranial aneurysms, but pose risk to perforating vessels crossed by the stent. The mechanism whereby some aneurysms become permanently occluded while other aneurysms recur remains unknown. This study tests the effects of stenting with and without endothelial denudation on rates of aneurysm healing and branch vessel occlusion. Through further understanding of the factors and forces involved in the formation of durable treatment results, we hope to develop strategies that will safely decrease the recurrence rate of endovascularly treated aneurysms.