Effect of Intraventricular tPA Following Aneurysmal Subarachnoid Hemorrhage

Inclusion Criteria: * Age greater than 18 years old. * SAH due to aneurysm, as determined by CT angiogram or cerebral angiogram. * Modified Fisher (mF) grade 3 or 4 SAH, defined as thick cisternal blood without (grade 3) or with (grade 4) intraventrciular blood. * Exclusion of the aneurysm from the parent circulation by endovascular embolization (Raymond class I or II) within 48 hours of ictus. * Ventriculostomy placement must occur prior to randomization. * Informed consent obtained from the patient or patient's decision maker Exclusion Criteria: * Determination by treating physician(s) that no ventriculostomy is needed. * Presence of intrinsic clotting disorders (e.g. due to hepatic failure, nephrotic syndrome, etc). Subjects whose pharmacologic anticoagulation is reversed, as determined by PT/INR, PTT within our institution's normal range, will be permitted to participate in this study. * Presence of significant anemia, defined as hemoglobin \< 8 gm/dL. * Patients who undergo endovascular techniques requiring post-operative dual anti-platelet therapy. * Residual aneurysm sac filling (Raymond class III occlusion). * Aneurysm or vessel perforation during the endovascular procedure. * Presence of craniectomy. * Significant neurologic disability prior to the onset of SAH. * Determination that administration of tPA/placebo cannot be initiated within 72 hours of symptom onset. * Presence of untreated intracranial aneurysms larger than 3mm on CT angiography or cerebral angiogram.