The Pathophysiology of Collateral Circulation in Acute Ischemic Stroke

Cerebral collateral circulation is a network of blood vessels which stabilizes blood flow and maintains cerebral perfusion whenever the main arteries fail to provide an adequate blood supply, as happens in ischemic stroke. These arterial networks are able to divert blood flow to hypoperfused cerebral areas. The extent of the collateral circulation determines the volume of the salvageable tissue, the so-called penumbra. Clinically, this is associated with greater efficacy of reperfusion therapies (thrombolysis and thrombectomy) in terms of better short- and long-term functional outcomes, lower incidence of hemorrhagic transformation and of malignant oedema, and smaller cerebral infarctions. Recent advancements in brain imaging techniques (CT and MRI) allow us to study these anastomotic networks in detail and increase the likelihood of making effective therapeutic choices. In this narrative review we will investigate the pathophysiology, the clinical aspects, and the possible diagnostic and therapeutic role of collateral circulation in acute ischemic stroke.

Automated summary

Cerebral collateral circulation is a network of blood vessels that ensures adequate blood flow in the brain when the main arteries fail, as seen in ischemic stroke. The extent of this collateral circulation plays a crucial role in determining treatment efficacy and outcomes. The use of advanced brain imaging techniques has enabled a better understanding of these networks, leading to more effective therapeutic strategies. This narrative review discusses the pathophysiology, clinical aspects, and potential diagnostic and therapeutic roles of collateral circulation in acute ischemic stroke.