1114. Identification of the ruptured aneurysm in multiple intracranial aneurysms

Authors: Athanasios Petridis, MD, IFAANS; Evangelos Mavrakis; Igor Fischer; Andreas Raabe; Hans Jakob Steiger; Christian Fung (Duesseldorf, Germany)

Introduction: In patients with subarachnoid haemorrhage and multiple aneurysms it can be difficult to identify which aneurysm ruptured. Wrong assumptions could lead to treatment of an un-ruptured aneurysm leaving the ruptured one untreated. There is a need to objectively identify the ruptured aneurysm in cases with multiple intracranial aneurysms. In the present study we aim to characterize factors which would indicate the ruptured aneurysm minimizing the risk of treating the incidental one. Methods: Retrospective study on patients with multiple aneurysms and subarachnoid haemorrhage caused by the rupture of one of them. Bicenter study of the Neurosurgical departments of the University Duesseldorf and Bern. Parameters investigated were: height, width, neck, shape, inflow angle, diameter of the proximal and distal arteries, width / neck ratio, aspeckt ratio, height / neck ratio, localization. Statistical analysis was performed by paired analysis. The bleeding aneurysm was identified intraoperatively or radiographically be distribution of blood. Results: N=186 patients with subarachnoid haemorrhage and multiple aneurysms were treated in both departments from 2008-2016 (Bern: 2008-2016, 725 patients and 100 multiple aneurysms, Duesseldorf: 2012-2016, 275 patients, 86 multiple aneurysms). The mean age was 57 ± 12 years. N=111 patients had 2 aneurysms N=52 patients had 3 aneurysms, N=14 had 4 aneurysms and N=1 had 5 aneurysms. It could be seen that the ruptured aneurysm had a mean size of 4,88 mm (for height) and was significantly bigger compared to the rest of the aneurysms (about 2x). Conclusion: As suspected in other studies aneurysms far smaller than 7 mm are prone to rupture. The 7 mm cut off is fictive and does not represent reality therefore should be abandoned. However, size matters. In this study as well as in our previous study with mirror aneurysms we show that in multiple aneurysms the biggest one is the one which ruptures.