Background and Purpose—Recurrent hemodynamic and neurological changes with persisting arterial occlusions may be attributable to cerebral blood flow steal from ischemic to nonaffected brain.

Methods—Transcranial Doppler monitoring with voluntary breath-holding and serial NIH Stroke Scale (NIHSS) scores were obtained in patients with acute middle cerebral artery or internal carotid artery occlusions. The steal phenomenon was detected as transient, spontaneous, or vasodilatory stimuli-induced velocity reductions in affected arteries at the time of velocity increase in normal vessels. The steal magnitude (%) was calculated as [(MFVm-MFVb)/MFVb]x100, where m=minimum and b=baseline mean flow velocities (MFV) during the 15- to 30-second period of a total 30 second of breath-holding.

Results—Six patients had steal phenomenon on transcranial Doppler (53 to 73 years, NIHSS 4 to 15 points). Steal magnitude ranged from -15.0% to -43.2%. All patients also had recurrent neurological worsening (>2 points increase in NIHSS scores) at stable blood pressure. In 3 of 5 patients receiving noninvasive ventilatory correction for snoring/sleep apnea, no further velocity or NIHSS score changes were noted.

Conclusions—Our descriptive study suggests possibility to detect and quantify the cerebral steal phenomenon in real-time. If the steal is confirmed as the cause of neurological worsening, reversed Robin Hood syndrome may identify a target group for testing blood pressure augmentation and noninvasive ventilatory correction in stroke patients.