The concept of acute cerebrovascular syndrome.

Early after the onset of transient ischemic attack (TIA), patients are at very high risk of stroke. There is no meaning to differentiate TIA in acute settings from acute ischemic stroke (AIS) only by the duration of symptoms. Acute TIA and AIS are on the same spectrum of acute ischemic syndrome in the central nervous system. We proposed a new concept termed acute cerebrovascular syndrome (ACVS), which includes TIA in acute settings and AIS. The concept of ACVS is comparable to acute coronary syndrome (ACS), which includes unstable angina and acute myocardial infarction. When a focal symptomatic reversible ischemia occurs in the brain, it is called TIA, and when a focal symptomatic irreversible ischemia occurs in the brain, it is called AIS. Patients with ACS share a single pathophysiological mechanism, that is rupture of unstable plaque followed by formation of platelet-rich thrombi to plug up coronary arteries. Unlike ACS, the mechanism of ACVS is complicated, which is not only large artery atherosclerosis similar to ACS but also cardioembolism or small vessel occlusion. In addition, there are no measurable biomarkers for ACVS, while there are practical biomarkers for ACS. Nevertheless, the concept of ACVS is practical to emphasize the importance of immediate evaluation and starting treatment to prevent subsequent stroke in acute settings of TIA. Therefore, TIA in acute settings as well as AIS should be recognized as ACVS, which is a medical emergency.