RT Journal Article SR Electronic T1 E-174 Severity of vasospasm associated with development of collaterals following aneurysmal subarachnoid hemorrhage JF Journal of NeuroInterventional Surgery JO J NeuroIntervent Surg FD BMJ Publishing Group Ltd. SP A135 OP A135 DO 10.1136/neurintsurg-2018-SNIS.250 VO 10 IS Suppl 2 A1 Al-Mufti, F A1 Manning, N A1 Crimmins, M A1 Amuluru, K A1 Majmundar, N A1 El-Ghanem, M A1 Patel, V A1 Agarwal, S A1 Park, S A1 Willey, J A1 Kamel, H A1 Connolly, S A1 Meyers, P A1 Claassen, J YR 2018 UL http://jnis.bmj.com/content/10/Suppl_2/A135.1.abstract AB Introduction Cerebral collateral circulation has been studied extensively in ischemic stroke where it has been shown to be a predictor of reperfusion, final infarct size, and outcome. Little is known about the significance of the collaterals in the setting of aneurysmal subarachnoid hemorrhage (aSAH). We sought to evaluate the effect of cerebral vasospasm on the development of cerebral collaterals following aneurysmal subarachnoid hemorrhage and the effects of the later on delayed cerebral ischemia (DCI).Methods We retrospectively evaluated 64 aSAH patients with evidence of DCI between day 5 and 7, enrolled in a prospectively maintained observational cohort study. Angiograms were evaluated by 4 blinded neurointerventionalists. We compared good collateral grades to poor collateral grades, additionally we compared enrolled individuals with any collaterals versus patients who had no collaterals.Results Inter-rater reliability for collateral grades was substantial (weighted kappa 0.632). Mild vasospasm was more frequent in patients with poor collateral grades compared to patients with good collateral grades (32% vs 4% p=0.012). There was no difference between the collateral groups with regards to DCI, functional or cognitive outcome. Patients adjudicated to have any collaterals were more likely to have severe vasospasm (62% vs 33% p=0.023) and less likely to have mild vasospasm (37% vs 9% p=0.007). In a multivariable model, vasospasm severity remained associated with collateral status, while aneurysm location was not.Conclusions The severity of vasospasm following aSAH was associated with the development of collaterals. There was no difference between collateral grades with regards to DCI or outcome.Disclosures F. Al-Mufti: None. N. Manning: None. M. Crimmins: None. K. Amuluru: None. N. Majmundar: None. M. El-Ghanem: None. V. Patel: None. S. Agarwal: None. S. Park: None. J. Willey: None. H. Kamel: None. S. Connolly: None. P. Meyers: None. J. Claassen: None.