Clinical and Imaging Features Associated with an Increased Risk of Early and Late Stroke in Patients with Symptomatic Carotid Disease

OBJECTIVE: The aim of this review was to identify clinical and/or imaging parameters that are associated with an increased (decreased) risk of early/late stroke in patients with symptomatic carotid disease. IN THE FIRST 14 DAYS: Natural history studies suggest that 8-15% of patients with 50-99% stenoses will suffer a stroke within 72 hours of their index symptom. Currently, there are insufficient validated data to identify highest-risk patients for emergency carotid endarterectomy (CEA), but an increased risk of stroke appears to be predicted by (i) an ABCD(2) score of 4-7; (ii) the presence of acute cerebral injury on CT/MRI; (iii) Gray Scale Median (GSM) <15, (iv) spontaneous embolisation on Transcranial Doppler (TCD); and (v) increased fluorodeoxyglucose (FDG) uptake in the carotid plaque on positron emission tomography (PET). A future goal must be to develop predictive algorithms (based on accessible imaging strategies) for identifying acutely symptomatic patients with highly unstable plaques for emergency CEA.

MEDIUM TO LONG TERM: In the randomised trials, about 70% of patients with symptomatic 70-99% stenoses were stroke-free on "best medical therapy" at 5 years. Clinical predictors of increased stroke risk include (i) male gender; (ii) age >75; (iii) hemispheric symptoms; and (iv) increasing comorbidity. Imaging features associated with increased stroke risk include (i) irregular stenoses; (ii) contralateral occlusion; (iii) increasing stenosis severity, but not subocclusion; (iv) tandem intracranial disease; (v) a failure to recruit intracranial collaterals; (vi) low GSM; (vii) MR diagnosis of intra-plaque haemorrhage; (vii) spontaneous embolisation on TCD; and (viii) increased FDG uptake in the carotid plaque on PET. Clinical/imaging parameters associated with a lower risk of stroke include (i) female gender, especially those with 50-99% stenoses; (ii) ocular symptoms/lacunar stroke; (iii) smooth stenoses; and (iv) chronic subocclusion.