Delayed postischemic hypoperfusion: a potentially damaging consequence of stroke.

Cerebral blood flow (CBF) was assessed with radioactive butanol and antipyrine during and after 1 hour of unilateral carotid artery occlusion in gerbils. Animals with clinical evidence of stroke demonstrated a marked fall in ipsilateral CBF during occlusion "no-reflow" phenomenon did not develop; instead, blood flow returned to normal 5 minutes after the termination of carotid occlusion. Flow subsequently fell to half the control value, however, and remained depressed for several hours despite local metabolic demands. This delayed imbalance in energy supply and demand creates a potential for additional brain damage that might be prevented by appropriate therapeutic intervention.