The field of endovascular or neurointerventional therapy for patients harboring various intra and extracranial processes has evolved significantly in the past decade. Currently, most tertiary care facilities offer these therapeutic maneuvers in the United States. Because medical care of this patient population is usually provided in the neurosciences critical care unit (NSU) it seems appropriate to discuss this topic in this book. We will describe current indications as well as pre-and postprocedural management in patients with acute ischemic stroke, arterial stenosis, subarachnoid hemorrhage (SAH), cerebral venous thrombosis (CVT), neoplasms, traumatic arterial lesions, and arteriovenous malformations (AVM).