In this study, we seek to determine if surgical anastomosis of the superficial temporal artery to the middle cerebral artery (STA-MCA) combined with best medical therapy can reduce subsequent ipsilateral ischemic stroke (fatal and non-fatal) at two years by 40%, despite perioperative stroke and death.  Eligible participants must have internal carotid artery occlusion producing hemispheric symptoms within the previous 120 days and  ipsilateral increased oxygen extraction fraction measured by positron emission tomography (PET).   We will test this hypothesis by conducting a randomized, non-blinded, controlled trial in 372 participants randomized equally to surgical or non-surgical treatment.