Stroke risk and critical carotid stenosis.
The risk of stroke from carotid stenosis is proportionate to the degree of stenosis, but whether this is a direct and linear relationship is unknown. Using the degree of carotid stenosis in 500 patients with asymptomatic carotid bruits as a continuous variable, we plotted the frequency distribution and related this to the risk of ischaemic cerebral events and the progression of the arterial lesion. There was a bi-modal distribution, with the junction of the two populations at 85% stenosis. The frequency of ischaemic cerebral events was maximal at 75-90% stenosis. Our data suggest that there is a critical degree of carotid stenosis at which stroke risk becomes maximal. This may represent a window of therapeutic opportunity.
Norris
J W
JW
Stroke Research Unit, Sunnybrook Medical Centre, University of Toronto, Canada.
Zhu
C Z
CZ
D002340:Carotid Artery Diseases / Q000175:diagnosis*; D002343:Carotid Artery, Internal / Q000473:pathology; D002544:Cerebral Infarction / Q000175:diagnosis*; D003251:Constriction, Pathologic / Q000175:diagnosis; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002546:Ischemic Attack, Transient / Q000175:diagnosis; D011446:Prospective Studies; D014463:Ultrasonography