Endovascular coil embolization for saccular-shaped blood blister-like aneurysms of the internal carotid artery

Background: Because of their fragile and thin wall, ruptured blood blister-like aneurysms (BBAs) at the anterior wall of the internal carotid artery (ICA) are difficult to manage, both surgically, as well as endovascularly. BBA is usually a tiny and broad-necked aneurysm, but it occasionally demonstrates a relatively saccular-like shape. In addition, the pseudoaneurysm sac often assumes a saccular shape. In this paper, the authors present their experience in treating these saccular-shaped BBAs endovascularly with coil packing. Method: Nine saccular-shaped ruptured BBAs in nine patients (one male and eight females; mean age 51.3 years, range 38-76) were treated with coil packing of the lesion between January 2006 and August 2010 in Nagoya University and its affiliated hospitals. Clinical, procedural, and angiographic data were retrospectively evaluated. Findings: Seven BBAs were treated by balloon-assisted coil embolization. Two remaining BBAs were embolized without balloon inflation, though a balloon catheter was on standby at the ICA. In one case, in which a saccular coil embolization could not be achieved, ICA trapping was performed. Three (33.3%) were treated in acute, two (22.2%) in subacute, and four (44.4%) in chronic period. One (11.1%) intraoperative rupture occurred. Six (66.7%) had excellent clinical outcomes, while two (22.2%) proved fatal outcomes. During the follow-up period (mean 18.9 months, range 4-48), two out of seven (28.6%) aneurysms presented an angiographical recurrence, but both were treated by coil embolization without complications. The remaining five (71.4%) aneurysms were completely resolved. Conclusions: Endovascular coil embolization can be considered as an alternative treatment option for selective saccular-shaped BBAs.