555 A Shift from Open to Endovascular Repair in the Treatment of Ruptured Middle Cerebral Artery Aneurysms and its Association With Improved 6-Month Functional Outcomes: A Single Institution Experience

INTRODUCTION: Middle cerebral aneurysms were underrepresented in the two largest trials (BRAT and ISAT) for the treatment of ruptured intracranial aneurysms. Recent institutional series addressing the choice between endovascular or open repair for this subset of aneurysms are few and have not yielded a definitive conclusion. METHODS: We conducted a retrospective review of 138 consecutive patients with ruptured middle cerebral artery aneurysms admitted into our institution from March 2009 to March 2019 to compare endovascular and open surgical outcomes. RESULTS: Of the ruptured middle cerebral artery aneurysms, 57 underwent endovascular repair while 81 were treated with open surgery. Over the study period there was a notable shift in practice toward more frequent endovascular treatment of ruptured MCA aneurysms (31% in 2008 vs. 91% in 2018). At discharge (49.1% vs 29.6%; p = .002) and at 6 months (84.3% vs 58.6%; p = 0.003), patients who underwent endovascular repair had a higher proportion of patients with good clinical outcomes (mRS 0-2) compared to those undergoing open surgery. Long term follow-up data (endovascular: 54.9 ± 37.9 months vs clipping: 18.6 ± 13.4 months) showed rebleeding (1.8% vs 3.7%, p = 0.642) and retreatment (5.3% vs 3.7%, p=0.691) in both groups. CONCLUSIONS: Our data suggest that endovascular repair was a feasible treatment strategy associated with improved functional outcome at 6 months. Future randomized trials for MCA aneurysms could further clarify the roles of these treatment modalities.