The significance of collateral circulation in acute ischemic stroke

The human brain accounts for about 2% of the total body weight, but it consumes about 15% of cardiac output and about 20% of the total body energy at rest [1]. The neurovascular coupling in the brain is a mechanism that increases the blood flow in the part of the brain where neurons are the most active [1]. If, for whatever reason, the blood flow drops below the threshold and there is a loss of ionic homeostasis and anoxic depolarization, consequent neuronal necrosis, i.e. brain infarction develops. Complete arrest of blood supply, or inadequate supply of neurons with glucose and oxygen, leads to metabolic and neuronal disorders (within 30 seconds), then functional disorders occur (after 1 minute), and finally (after 5 minutes) irreversible changes and neuronal death occur; this leads to brain infarction, which clinically manifests as ischemic stroke [2]. If the flow of oxygenated blood is re-established quickly enough, the neuronal damage is reversible.