BACKGROUND AND PURPOSE: The most common cause of poor treatment outcome in patients suffering aneurysmal subarachnoid hemorrhage is cerebral vasospasm, especially in cases of poor Hunt and Hess grades (IV and V). A further prognostic factor in surgically treated patients is aneurysm localization. The aim of the present retrospective study is to compare the endovascular treatment outcome in such poor-grade patients according to aneurysm localization in either the anterior (AC) or posterior (PC) circulation. METHODS: Forty poor-grade patients admitted between 1993 and July 1998 were treated by endovascular approach within 23 days after aneurysm rupture. Eighteen had aneurysms in the AC, 22 in the PC. Mean treatment delay was 4 days after rupture and median, 2 days. One patient showed multiple aneurysms. In 36 cases, aneurysms were occluded by Guglielmi detachable coils; in 4 cases, by parent vessel balloon occlusion. RESULTS: The incidence of delayed ischemic neurological dysfunction or cerebral infarct due to vasospasm did not differ significantly between the AC and PC groups. Two procedure-related complications with clinical effect were observed in each group. At 6 months' follow-up, the result was good in 5 patients and poor in 13 in the AC group and good in 11 patients and poor in 11 in the PC group. CONCLUSION: Given comparable incidence of vasospasm in poor-grade patients, a tendency toward better treatment outcome was found in patients with aneurysms in the posterior circulation (chi(2)=2.04; P=0.15) than in the anterior circulation. Endovascular therapy for poor-grade patients is recommended, as are further studies to determine treatment differences.
