 Acute ischemic stroke AIS affects over 700,000 Americans every year and is the leading cause of long-term disability. Early neurological deterioration after AIS typically occurs within 72 hours of stroke onset and affects 30 of all stroke patients, who have a higher rate of death or poor outcome. Several mechanisms account for early neurological deterioration, including hemorrhagic conversion, systemic illness, cerebral edema, and seizure, but the most common cause is extension of the stroke into the penumbra, a region of salvageable brain tissue surrounding the core of irreversible ischemic infarct. The penumbra is tenuously perfused by collateral blood vessels. AIS management is primarily focused on recanalizing the occluded artery causing the stroke, but an alternative and relatively unexplored approach is optimization of collateral blood flow. 