Carotid Plaque Score for Stroke and Cardiovascular Risk Prediction in a Middle-Aged Cohort From the General Population

Abstract

Background We aimed to explore the predictive value of the carotid plaque score, compared with the Systematic Coronary Risk Evaluation 2 (SCORE2) risk prediction algorithm, on incident ischemic stroke and major adverse cardiovascular events and establish a prognostic cutoff of the carotid plaque score. Methods and Results In the prospective ACE 1950 (Akershus Cardiac Examination 1950 study), carotid plaque score was calculated with ultrasonography at inclusion in 2012 to 2015. The largest plaque diameter in each extracranial segment of the carotid artery on both sides was scored from 0 to 3 points. The sum of points in all segments provided the carotid plaque score. The cohort was followed up by linkage to national registries for incident ischemic stroke and major adverse cardiovascular events (nonfatal ischemic stroke, nonfatal myocardial infarction, and cardiovascular death) throughout 2020. Carotid plaque score was available in 3650 (98.5%) participants, with mean±SD age of 63.9±0.64 years at inclusion. Only 462 (12.7%) participants were free of plaque, and and 970 (26.6%) had a carotid plaque score of >3. Carotid plaque score predicted ischemic stroke (hazard ratio [HR], 1.25 [95% CI, 1.15-1.36]) and major adverse cardiovascular events (HR, 1.21 [95% CI, 1.14-1.27]) after adjustment for SCORE2 and provided strong incremental prognostic information to SCORE2. The best cutoff value of carotid plaque score for ischemic stroke was >3, with positive predictive value of 2.5% and negative predictive value of 99.3%. Conclusions The carotid plaque score is a strong predictor of ischemic stroke and major adverse cardiovascular events, and it provides incremental prognostic information to SCORE2 for risk prediction. A cutoff score of >3 seems to be suitable to discriminate high-risk subjects. Registration Information clinicaltrials.gov. Identifier: NCT01555411.

Keywords: atherosclerosis; cardiovascular disease; carotid plaque; prediction; stroke; ultrasonography.

Figure 1. Calculation of carotid plaque score.

Top: B‐mode still image of the left carotid bifurcation, longitudinal plane. A carotid plaque with the largest diameter of 2.1 mm is located at the far wall of the artery. According to the carotid plaque scoring system (plaque diameters ≥1.5, ≥2.5, and ≥3.5 mm are given 1, 2, and 3 points, respectively), the plaque is given 1 point. The sum of the largest plaque in each extracranial segment of the carotid artery, both sides (common carotid artery [CCA], carotid bifurcation, internal carotid artery [ICA], and external carotid artery [ECA]), constitutes the carotid plaque score, ranging from 0 to 24. A score of 0 denotes a subject free of plaques. Bottom: the 4 segments of the carotid artery (1 side) in longitudinal plane. A 1.9‐mm plaque in CCA and a 2.6‐mm plaque in ICA are seen, representing a plaque score of 3 on this side. The sum of the 4 segments on both sides provides the carotid plaque score.

Figure 2. Flowchart of the study population.

ACE 1950 indicates Akershus Cardiac Examination 1950 study; and SCORE2, Systematic Coronary Risk Evaluation 2.

Figure 3. Carotid plaque score distribution.

The x axis shows the number of participants. The y axis shows the plaque score. ♀ Indicates female; and ♂, male.

Figure 4. Proportion of ischemic stroke, myocardial infarction, and cardiovascular death in major adverse cardiovascular events.