Additionally, increased blood and CSF levels of certain inflammatory biomarkers (IL-6, hsCRP, etc) have been correlated to aSAH patients with poor clinical outcomes. Unfractionated heparin (UFH) has known anti-inflammatory actions. As a result, a secondary objective of this study will be to evaluate whether LDIVH can reduce blood and CSF inflammatory biomarkers levels compared to controls and whether there is any association between inflammatory biomarker levels and cognitive outcomes in aSAH.