1063. De novo aneurysm formation in patients with at least one diagnosed intracranial aneurysm in history.

Authors: Athanasios Petridis, MD, IFAANS; Eleni Vourla; Jan Cornelius; Hans Jakob Steiger (Duesseldorf, Germany)

Introduction: There are various data about the incidence of aneurysm development and when they occur during live time. In the present study we focused on the occurrence of new aneurysms in patients which were already treated for intracranial aneurysms. Methods: Retrospective study on patients treated in our department form 2000-2011 and followed up until November 1 st 2017. CTA and MRA during follow-up visits were evaluated and analysed for de novo aneurysms as well as reperfusion on the treated aneurysms. Risk factors like hypertonia and nicotine were evaluated in respect to aneurysm Formation. Results: N=130 patients with intracranial aneurysm treatment were analysed. N=63 of the patients received microsurgical clipping for an aneurysm and N=67 had an endovascular coiling.New aneurysms occurred in 10 / 130 patients (7,6 %) in a mean time of 7,9 ±2,9 years. There was no association of de novo aneurysms and localisation of the treated aneurysms, nicotine, hypertonia or gender. Re-perfusion occurred in just 2/63 (3,1%) cases treated microsurgically and in 26/67 (38,8%) cases treated endovascularlly. One of these re-perfused and coiled aneurysms bled (1/26, 3,8 %). AcomA and basilar aneurysms had a re-perfusion rate of 32% and 50% respectively. The mean time of reperfusion was 3,82 ± 3,3, years. The complication rate of microsurgical treatment was 11,2% (infarctions and bleeding) and of endovascular treatment 5,9% (infarctions). Conclusion: The occurrence ofnew aneurysms in patients already diagnosed with one or more aneurysms is 7,6% in 8 years. The complication rate of microsurgical treatment is higher compared to endovascular treatment by about 6% difference (2x). However, the reperfusion rate of endovascularly treated aneurysms was significantly higher compared to microsurgical treatment (12x). We could assume a reperfusion of endovascularly treated aneurysms in 4 years in 1/3 of patients with a bleeding risk of 1 in 300 patient years.