Abstract 108: Long-Term Outcome of Giant Unruptured Intracranial Aneurysms

Abstract

Introduction: Giant intracranial aneurysms are uncommon, have a high risk for rupture and are difficult to treat. The International Study of Unruptured Intracranial Aneurysms (ISUIA) prospective cohort included 187 patients with maximal diameter of 25 mm or greater. This analysis was to determine the long-term prognosis of these aneurysms both treated and untreated. Methods: Patients were enrolled into ISUIA at 61 centers from 1991-1998. A prospective cohort included the managed with observation, surgery or endovascular treatment. Patients were followed for a median of 9.2 years. Aneurysms were measured using a central reading of bi-planar cerebral angiography. Outcomes were determined prospectively and with central review. Results: 187 patients with a maximum diameter of 25 mm were followed. The mean size was 30.3 mm, ranging from 25 to 63 mm. 39% of the aneurysms were surgically treated at baseline, 27% were endovascularly treated, and 32% were managed conservatively;3% had subsequent endovascular treatment and 5% surgical treatment. Patients with giant aneurysms were predominantly women (83%), had a baseline Rankin Score of in 93%, were located predominantly in the anterior circulation (internal carotid 44%, cavernous ICA 28%, middle cerebral 12%). 80% of the patients were symptomatic with cranial nerve deficit in 47% (III and VI nerves), mass effect in 16%, headaches in 44%, orbital pain in 21%, and vision loss in 25%. Smoking history was present in 67%, hypertension in 44%, vascular headaches in 29% and family history in 10%. 70 patients (39%) died during follow-up however 59% were still Rankin 1 or 2. Both surgical and endovascular treated patients had 60-64% good outcome and 34-36% mortality. Untreated patients had a 57% mortality. Subarachnoid hemorrhage occurred in 11 untreated patients and 12 treated patients with most occurring in the first year. Conclusions: Giant intracranial aneurysms are typically symptomatic, and have a high risk of rupture early after diagnosis. Outcome was similar with surgical and endovascular treatment but post-procedure hemorrhage did occur.