Abstract Number ‐ 129: Intracranial Blister Aneurysm Management: An Australian Multi‐Centre Retrospective Analysis

Introduction Blister aneurysms (BA) are high risk neurovascular lesions that account for 1% of all intracranial aneurysms. The pathology of BAs, with defective vessel wall and broad‐based neck, make this clinical entity particularly difficult to treat. When these aneurysms present with acute subarachnoid haemorrhage there are associated with high rates of re‐rupture and mortality. These pose substantial challenges for both endovascular and microsurgical management. We report a multi‐centre retrospective analysis of BA management in Sydney, Australia, to describe the different surgical and endovascular approaches and the associated clinical outcomes. Methods A multicentre review of two large tertiary hospitals in Sydney with a search for imaging databases were screened for term of “blister” in all head and neck imaging modalities from January 2010 to June 2022. Operation reports were also screened for the 5‐year time period since cerebral angiogramreports transitioned from imaging database to surgical database. All identified reports were manually screened for confirmed diagnosis of blister aneurysm. Results 21 cases with confirmed diagnosis of blister aneurysm that underwent management at respective facilities were included. 16 cases (76%) were managed endovascularly – one with stent‐assisted coiling and 15 with flow diversion stents. 4 cases (19%) were managed surgically – 3 of these were primary clipping, and one wrap and clipping technique. One surgical case was commenced as an endovascular case prior to conversion. One case was managed conservatively (5%). Clinical outcomes were discharge disposition, occlusion of aneurysm and post‐operative complications. Conclusions BAs have challenging therapeutic considerations with a high mortality and morbidity. Endovascular treatment offers a less invasive management option with a trend of lower rates of intraoperative rupture and lower mortality rates. Endovascular therapy had higher rates of retreatment and incomplete aneurysm occlusion on follow up imaging. Patients discharged directly home were comparable between groups. The decision making for blister aneurysms is complex, endovascular treatment shows promise for acute treatment but careful consideration of antithrombotic regime and requirement for EVD insertion or further surgery should be considered.