Contemporary vascular neurosurgery cannot sometimes avoid electively used focal brain ischemia. In aneurysm surgery, for example, it is sometimes necessary to close temporarily the parent vessel for a safer dissection of the aneurysm sac. Also carotid endarterectomy cannot be done without a temporary closure of the artery. One of possible neuroprotective methods to be used during this controled focal ischemia is a systemic hypertension. The knowledge of anatomical and functional capabilities of the brain circulation is crucial for understanding the advantages but also the limits of this neuroprotective method.

        Key words: systemic hypertension, brain ischemia