This was a prospective, multicenter, cohort study of patients undergoing medical intervention for
vascular disease. Hazard ratios for ICA
stenosis, clinical features, and plaque texture features associated with ipsilateral cerebrovascular or
retinal ischemic (CORI) events were calculated using proportional hazards models.
RESULTS: A total of 1121 patients with 50% to 99% asymptomatic ICA
stenosis in relation to the bulb (European Carotid Surgery Trial [ECST] method) were followed-up for 6 to 96 months (mean, 48). 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
transient ischemic attacks (TIAs) or
stroke, low grayscale median (GSM), increased plaque area, plaque types 1, 2, and 3, and the presence of discrete white areas (DWAs) without acoustic shadowing were associated with increased risk. Receiver operating characteristic (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% confidence interval [CI] 0.54-0.64), 0.66 (0.62-0.72), and 0.82 (0.78-0.86), respectively. In the last model,
stenosis, history of contralateral TIAs or
stroke, GSM, plaque area, and DWAs 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 5-year
stroke rate was <5% in 495, 5% to 9.9% in 202, 10% to 19.9% in 142, and ≥ 20% in 84 patients.
CONCLUSION: Cerebrovascular risk stratification is possible using a combination of clinical and ultrasonic plaque features. These findings need to be validated in additional prospective studies of patients receiving optimal medical intervention alone.