Impact of aneurysm location on hemorrhage risk

Introduction: Recent studies have reinforced anterior communicating (AComm) artery location as a significant risk factor for aneurysm rupture in addition to posterior circulation/posterior communicating (PComm) artery location. However, studies stratifying aneurysm location in greater detail are sparse. Methods: We reviewed the records of 747 consecutive patients with 1013 aneurysms seen at our institution over a 7 year period, noting aneurysm location and rupture status at the time of presentation. Results: High proportions of ruptured aneurysms were seen among frontopolar/pericallosal (59%. OR 3.07, p = 0.011), vertebral/posteroinferior cerebellar (PICA: 53%, OR 2.49, p = 0.0037), AComm (50%, OR 2.46, p < 0.0001). and PComm aneurysms (44%, OR 1.77, p = 0.0016). Low proportions of ruptured aneurysms were seen among superior hypophyseal artery (SHA; 6%, OR 0.12, p = 0.0001), internal carotid artery (ICA) bifurcation (12%, OR 0.27, p = 0.0012), and ophthalmic artery aneurysms (15%, OR 0.33, p = 0.0002). The proportion of ruptured PComm aneurysms demonstrated a trend toward being greater than anterior choroidal artery aneurysms (OR 2.14, p = 0.09); however the proportion was significantly greater among anterior choroidal artery aneurysms as compared to nonPComm intradural ICA aneurysms (OR 2.78, p = 0.03). Notably, the lower rupture rate of SHA aneurysms as compared to ophthalmic artery aneurysms neared statistical significance (OR 0.38, p = 0.10). Conclusion: Aneurysm location has a significant impact on risk of rupture and should be stratified in greater detail in future studies of aneurysm natural history. (C) 2014 Elsevier B.V. All rights reserved.