Blood blister-like aneurysms: single center experience and systematic literature review

Blood blister-like aneurysms (BBAs) are a controversial entity. They arise from non-branching sites on the supraclinoid internal carotid artery (ICA) and are suspected to originate from a dissection. Our aim is to describe the BBA cases seen in our center and to present a systematic review of the literature on BBAs. We analyzed the eleven cases of BBA admitted to our center from 2003 to 2012. We assessed the medical history, treatment modality (endovascular and/or surgery), complications and clinical outcome. The cohort included 8 women and 4 men with a mean age of 53.16 years. Treatment of the BBA consisted of stenting and coiling in 5 patients, stenting only in 4 patients, coiling and clipping in 1 patient, clipping only in 1 patient, and conservative treatment in 1 patient. A good outcome was found in 10 patients, as defined by a modified Rankin Scale (mRS) less than or equal to two at three months. A systematic review of the literature was performed, and 314 reported patients were found: 221 patients were treated with a primarily surgical approach, and 87 patients were treated with a primarily endovascular approach. A rescue or second treatment was required in 46 patients (21%). The overall estimated treatment morbidity rate was 17%, and the mortality rate was 15%. BBAs exhibit more aggressive behavior compared to saccular aneurysms, and more intra-operative complications occur with BBAs, independent of the treatment type offered. They are also significantly more likely to relapse and rebleed after treatment. Endovascular treatment offers a lower morbidity-mortality compared with surgical approaches. Multilayer flow-diverting stents appear to be a promising strategy.