All patients fulfilling the inclusion and exclusion criteria and who are willing to participate will receive intervention to induce hypertension, including intravenous saline, phenylephrine (neosynephrine) or levophed, and possibly oral midodrine. Blood pressure will be increased to a maximum mean arterial pressure (MAP) that is 30% above the baseline MAP as measured in the emergency department. The acute phase of the study will last for 3-5 days (for responders) and all patients will be followed up at 1 and 3 months post stroke onset. All patients will undergo neurologic, cognitive, and physical examinations as well as serial MRI studies with diffusion and perfusion-weighted imaging.