Severe Asymptomatic Carotid Artery Stenosis Risk Model Accurate at Detection

A risk model can accurately identify patients with a high risk for severe asymptomatic carotid artery stenosis (ACAS) among those with atherothrombotic disease or multiple atherothrombotic risk factors, according to a study in Stroke.

Researchers validated a risk model for the prevalence of asymptomatic carotid artery stenosis (PACAS) using severe baseline ACAS as the predicted outcome, which was defined as narrowing of the carotid artery of 70% or more. They also calculated the incidence of fatal or nonfatal stroke and CVD events (composite of nonfatal or fatal stroke or myocardial infarction, or vascular death) during follow-up.

Data were obtained from patients in the REACH registry, which enrolled participants from 2003 to 2004 who were aged 45 years or older from 5000 sites in 44 countries, and who had symptomatic coronary artery disease, cerebrovascular disease, peripheral artery disease, or at least 3 predefined atherothrombotic risk factors.

The PACAS model included age, sex, and vascular risk factors such as smoking status, diabetes, and history of stroke or transient ischemic attack, among others, as predictors. Incidence rates of stroke and CVD were calculated during follow-up for 4 risk groups.

The cohort included 26,384 patients (mean age, 66 years; 65% men), of whom 1662 (6.3%) had severe baseline ACAS. The discriminative performance of the PACAS showed an area under the receiver operating characteristic (AUROC) curve of 0.65 (95% CI, 0.64-0.67), which was slightly increased using the risk equation, with an AUROC curve of 0.67 (95% CI, 0.65-0.68). The calibration plot had good concordance between the predicted and observed prevalence of severe baseline ACAS after recalibration.

In a mean follow-up of 2.7 years (70,799 patient-years for stroke and 69,949 for CVD), 1124 patients had a stroke and 2484 had CVD. Stroke and CVD incidence rates were significantly increased for patients with severe baseline ACAS vs those without severe ACAS, with an incidence rate ratio of 1.97 (95% CI, 1.62-2.38) and 1.89 (95% CI, 1.66-2.15), respectively.

Incidence rates of stroke in patients with ACAS increased with higher PACAS sum scores, with a similar increase occurring for incidence rates of CVD.

Selective screening for severe ACAS among patients who had PACAS sum scores of 14 or higher yielded a prevalence of 11.4%, with a number needed to screen (NNS) of 9. Selective screening for severe ACAS in patients who had PACAS sum scores of 18 or higher had a prevalence of 23.9%, with an NNS of 4.

Limitations include the unknown status of the carotid arteries in a substantial proportion of patients, and there were potential differences in determining the degree of stenosis among centers. In addition, recruitment of the REACH registry ended about 20 years ago, and the follow-up was relatively short.

“…[because] incidence rates of stroke and CVD during follow-up were significantly elevated in patients with higher PACAS sum scores, selective screening using the PACAS risk model will detect patients with ACAS at high risk of major adverse cardiovascular events,” the investigators wrote.

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on The Cardiology Advisor