Abstract TP422: Comparison of Natural History and Effect of Intracranial Stent Placement Between Patients With Intra-Dural and Those With Sub-Arachnoid Intracranial Arterial Stenosis

Abstract

Background: Intracranial stenosis can be located in intradural or subarachnoid space. It is unclear whether there are any differences in ipsilateral ischemic stroke risk, cerebral hemorrhage and death in response to stent placement in these two locations. Methods: We analyzed Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis (SAMMPRIS) data. We divided the patients based on location of arterial stenosis: intradural [petrous internal carotid artery (ICA), pre-cavernous ICA, cavernous ICA or pre-posterior inferior cerebellar artery (PICA) vertebral artery] and subarachnoid [post-cavernous ICA, middle cerebral artery, vertebral artery at the level of or distal to origin of PICA, or basilar artery]. Cox proportional hazards analyses were used to determine the effect of intradural versus subarachnoid location on risk of ipsilateral ischemic stroke, cerebral hemorrhage or death during the follow-up period. Results: A total of 451 patients with stenosis located in intradural (n=74, 16.4%) or subarachnoid (n=377, 83.5 %) spaces were followed for a mean (SD) period of 29.06 (15.22) months after randomization. The rate of ischemic stroke seen in intradural and subarachnoid spaces was 11.86% and 14.58%, respectively. The rate of cerebral hemorrhage in the intradural and subarachnoid spaces was 1.35% and 2.92 %, respectively. The rate of death in the intradural and subarachnoid spaces was 10.81% and 1.59%, respectively. In Cox proportional hazards analyses, the risk of ipsilateral ischemic stroke (HR 1.08, P = 0.46), cerebral hemorrhage (HR 1.05, P = 0.59) and death (HR 0.9, P = 0.9) was not significantly different between patients with intradural arterial stenosis and those with subarachnoid arterial stenosis. The interaction between location of stenosis and treatment (intracranial stent versus best medical treatment) was not significant for the either ipsilateral ischemic stroke (p= 0.21), cerebral hemorrhage (p= 0.18) or death (p=0.15). Conclusion: We did not find any evidence to suggest that there was any difference in natural history or response to intracranial stent placement in patients with intradural location of stenosis compared with those with subarachnoid location.