LAUSR

BACKGROUND Blood blister-like aneurysms (BBLA) are rare, challenging to treat, and prone to rerupture. We analyzed our results in relationship to type of BBLA and other prognostic factors. METHODS Data on patient and aneurysm characteristics, clinical course, and treatment results, including data from patient records and review of imaging findings, were collected prospectively and analyzed retrospectively. RESULTS There were 27 patients (mean age 56 years) with subarachnoid hemorrhage from BBLA. Of patients, 13 (48%) had BBLA of the internal carotid artery, 6 had BBLA of the anterior cerebral artery (22%), 5 had BBLA of the middle cerebral artery (19%), and 3 had BBLA of the basilar artery (11%). Most patients (n = 12) had a circumferential type IV BBLA (44%). BBLAs were treated by clip-reinforced wrapping in 13 patients (48%) and by clipping alone in 8 patients (30%); 3 (11%) patients received no treatment. The 3 remaining patients were treated endovascularly, by combined treatment, or by fenestration tube technique. Rerupture after treatment occurred in 4 patients (15%), all of whom had type IV BBLAs. Outcome was unfavorable (modified Rankin scale score 3-6) in 52% (n = 14). The highest rates of rerupture (33%), delayed infarctions (67%), unfavorable outcome (75%), and death (50%) were identified in type IV BBLAs; type I-III BBLAs had a better course. CONCLUSIONS Treatment of BBLA is challenging. Patients with type IV BBLAs were especially prone to rerupture, delayed infarctions, unfavorable outcomes, and death. Independent risk factors for unfavorable outcome were advanced age (≥60 years) and type IV BBLA.