Irregular Shape Identifies Ruptured Intracranial Aneurysm in Subarachnoid Hemorrhage Patients With Multiple Aneurysms

Background and Purpose-We investigated which aneurysm-related risk factors for rupture best discriminate ruptured versus unruptured saccular intracranial aneurysms (sIAs) in subarachnoid hemorrhage patients with multiple sIAs. Methods-We included 264 subarachnoid hemorrhage patients with a ruptured sIA and at least one additional unruptured sIA, from the Kuopio Intracranial Aneurysm database from 2003 to 2015. These patients had 268 ruptured and 445 unruptured sIAs. Angiograms of the 713 sIAs were reevaluated for multiple variables describing aneurysm shape. Multivariate generalized linear mixed models were used to calculate odds ratios with corresponding 95% confidence intervals for the independent risk factors for aneurysm rupture. Results-In the multivariate analysis, only sIA size (P<0.004) and irregular shape (P<0.000) independently associated with sIA rupture. As an independent risk factor, irregular shape showed the strongest association with rupture (odds ratio 90.3; 95% confidence interval, 47.0-173.5). The sIA location, flow angles, bottleneck factor, or aspect ratio were not significantly associated with rupture. Conclusions-Irregular shape may identify the ruptured sIA better than size in patients presenting with aSAH and multiple sIAs.