Brain Disorders & Therapy

Asymptomatic carotid stenosis and risk stratification

Global Summit on Stroke

August 03-05, 2015 Birmingham, UK

Andrew Nicolaides

Posters-Accepted Abstracts: Brain Disord Ther

Abstract:

Best evidence indicates that the annual risk of ipsilateral cerebral stroke in patients with moderate-severe asymptomatic
internal carotid stenosis (ACS) receiving optimal medical intervention alone has fallen to approximately 1% making
routine carotid endarterectomy unjustified. However, if patient subgroups with sufficiently higher average risk, despite current
optimal medical intervention could be reliably identified then carotid surgery may still be justified.The ACSRS performed
under the auspices of the IUA was a prospective, multicentre, cohort study of patients undergoing medical intervention for
vascular disease that has answered this question. Hazard ratios for stenosis, clinical features and plaque texture features
associated with ipsilateral cerebrovascular or retinal ischemic (CORI) events were calculated using proportional hazards
models.1121 patients with 50-99% asymptomatic ICA stenosis in relation to the bulb (ECST method) were followed-up for
6-96 (mean 48) months. A total of 130 ipsilateral CORI events occurred. Severity of stenosis, age, systolic blood pressure,
increased serum creatinine, smoking history of more than 10 pack-years, history of contralateral TIAs or stroke, low gray scale
median (GSM), increased plaque area, plaque types 1, 2 and 3 and presence of discrete white areas without acoustic shadowing
(DWA) were associated with increased risk. ROC curves were constructed for predicted risk versus observed CORI events as a
measure of model validity. The areas under the ROC curves for a model of stenosis alone, a model of stenosis combined with
clinical features and a model of stenosis combined with clinical and plaque features were 0.59 (95% CI 0.54 to 0.64), 0.66
(0.62 to 0.72) and 0.82 (0.78 to 0.86) respectively. In the last model, stenosis, history of contralateral TIAs or stroke, GSM,
plaque area and DWA were independent predictors of ipsilateral CORI events. Combinations of these could stratify patients
into different levels of risk for ipsilateral CORI and stroke with predicted risk close to observed risk. Of the 923 patients with
≥70% stenosis, the predicted cumulative five year stroke rate was <5% in 495, 5-9.9% in 202, 10-19.9% in 142 and ≥20% in
84 patients.Thus, cerebrovascular risk stratification is possible using a combination of clinical and ultrasonic plaque features.