Acute and chronic carotid occlusion syndromes.

Clinical manifestations of acute internal carotid artery (ICA) occlusion are the most variable among all cerebrovascular syndromes. This extreme variability is related essentially to three variables: collateral circulation, cerebral vasoreactivity with hemodynamic factors, and the characteristics of occlusion. Intracranial circulation is represented by a mirabilis network connecting both anterior-posterior and deep-shallow circulation systems. The compensation mechanisms in ICA occlusion can be influenced by preexisting risk factors. Moreover, an alteration in cerebral hemodynamic function related to previous stroke, chronic hypoperfusion and vascular risk factors play a relevant role in the clinical features of ICA occlusion. On the other hand, also after an acute event, the clinical evolution in a patient with ICA occlusion, which is defined here as chronic occlusion, is extremely variable: some patients remain asymptomatic, while others suffer recurrent TIA or minor/major stroke. The factors set forth above associated with other underlying conditions also affect clinical development. However, a fundamental role is played by the proper management of vascular risk factors whether in acute or chronic ICA occlusion.