Noninvasive carotid studies are often performed in patients with asymptomatic neck bruit or in those who are to undergo cardiac, aortic, or peripheral vascular surgery. These are controversial uses of the vascular laboratory, except when carried out as research to determine the natural history of carotid disease.
Endarterectomy in the asymptomatic patient is a more individually defined procedure than investigations in those with symptoms, which can be more of a more standardised nature.
Even known tight carotid stenosis can run a harmless course in some people. Furthermore, knowledge of the presence of narrowing in the carotid artery can cause anxiety in patients.
The most common cause of arterial stenosis in the Western world is atherosclerosis, which is most prevalent in the cerebral vasculature at the carotid bifurcation. Because of this, it is important to determine the condition of the carotid bifurcation in many patients with stroke.
Brain infarction occurs when an artery is occluded or becomes stenotic to the point that an insufficient amount of blood is delivered to a portion of brain. Rupture of an artery or vein allows blood to flow into or around the brain.
The stroke syndrome consists of the rapid development of focal neurological deficit (generally within minutes) that is usually localised to an area of brain supplied by a specific artery.
The word stroke implies brain cell death caused by infarction, and thus the deficit endures for days and often longer.
A brief ischaemic episode is called TIA (transient ischaemic attack). Most TIAs last from 1 to 30 minutes, but they may be longer. According to common use and for epidemiological reasons, a neurological deficit lasting less than 24 hours and otherwise consistent with ischaemia is considered a TIA.