Blister aneurysms of are rare lesions representing a real challenge for diagnosis and management. They typically show small size, hemispherical shape, fragile wall, broad neck, and are arising from non-branching sites of intracranial arteries.
Materials and methods: We retrospectively reviewed all aneurysms treated at our institution. Seventeen patients (6 male, 11 female) with 17 blister aneurysms were identified (mean age 53.3, range 41-63 years). Clinical, procedural, angiographic data as well as follow up data were evaluated.
Results: All patients presented with aneurysmal subarachnoid hemorrhage. Majority of the blister aneurysms were located in ICA while 1 was located at posterior cerebral artery, 1 at vertebral and 1 involving basilar artery. All patients were treated using single or overlapping stents and if possible additional coiling. There was no intra-operative rupture. Good outcome (mrs 0-2) was seen in 14 patients. Poor clinical outcome (mrs 3-5) was seen in 2 patients due to vasospasm induced ischemic deficits at discharge, both of them improved on follow up (mrs 1 on follow up). There were 3 mortalities, One patient died of rebleeding while other 2 died due to SAH induced complications. Follow-up angiography was available in 16 patients (one patient died before follow up angiogram) and revealed complete or near complete aneurysm occlusion in 11, incomplete obliteration in 1 and no change in 2 cases. Two cases showed post-treatment angiographic aneurysm recurrence. Both cases were managed with repeat coiling and overlapping stent placement.
Conclusion: Endovascular management using single/overlapping stent and if possible coil placement is technically safe and feasible in blister aneurysms. Overlapping stents lead to better aneurysm occlusion than a single stent. Blister aneurysm in dorso-medial ICA showed higher tendency of continued growth/recurrence, higher incidence of clinical vasospasm and in these cases early angiographic follow-up is advisable. Repeat treatment should be considered promptly if necessary.