The formation mechanism of acute dissection of blood blister-like aneurysm and its implication of endovascular treatment

Background:Acute mural dissection of the anterior wall of the internal carotid artery which may contribute to the development of blood blister-like aneurysms(BBLAs)was postulated,and stenting or flow diversion treatment across the soi-disant aneurysm was reported in this study.Methods:From December 2016 to December 2018,8 patients presenting with subarachnoid hemorrhage(SAH)due to BBLA were subjected to endovascular treatment with stent-assisted coiling.Clinical outcomes were evaluated using a clinical outcome score scale.Results:Based on angiograms,pathologic change involving the supraclinoid segments of the internal carotid artery(ICA)adjacent to BBLA was found in all patients.This pathologic change meant a focal dissection of the supraclinoid segment of the ICA which constituted the pathogenesis of BBLAs.Closed-cell,open-cell,and braided stents were used in 1,1,and 6 patients,respectively.Complete obliteration was achieved following endovascular treatment among all 8 patients harboring BBLA.One re-bleeding successive to a closed-cell stent across the aneurysmal neck was observed.Follow-up angiograms revealed stable complete exclusion of all BBLAs from the parent vessel at 3 to 8 months.All patients had a favorable clinical outcome score of 0–1.Conclusions:Acute dissection of a focal point of the intracranial vessels underlies the development of BBLAs.Open-cell and braided-cell stent-assisted coiling may constitute appropriate treatment due to good apposition against the vascular walls.Adjunctive coils may facilitate immediate complete occlusion of BBLAs.