Performance of the Prevalence of asymptomatic Carotid artery Stenosis risk Score in the cohort of the Cyprus epidemiological Study on atherosclerosis

Background: There has been a continuous debate on the value of screening for asymptomatic carotid artery stenosis (CAS) because of the low prevalence in the general population as well as the risk of complications associated with surgical intervention. The aim of the study was to determine the association between the Prevalence of Asymptomatic Carotid Artery Stenosis (PACAS) risk score and (a) the prevalence of asymptomatic CAS ≥50%, ≥70%, <50%, and the prevalence of two or more bifurcations with plaque (carotid or common femoral), (b) the risk of stroke/transient ischemic attack (TIA) and atherosclerotic cardiovascular disease (ASCVD), and (c) the effect of two or more bifurcations (carotid or common femoral) with plaque (BWP) in up classifying subjects into higher risk in the cohort of the Cyprus Epidemiological Study on Atherosclerosis (CESA). Methods: CESA is a prospective study in the Republic of Cyprus with 1102 subjects aged 40-89 at baseline of which 1000 were free of ASCVD at recruitment. Follow-up was for a mean of 15.5±4.6 years (range 1-20). Both carotid bifurcations and both common femoral bifurcations were scanned with ultrasound to determine presence of plaques and degree of CAS. Results: The prevalence of CAS ≥50% and ≥70% in the cohort was 3.3% and 0.7% respectively. A PACAS score of ≥11 (11-20) was able to identify a subgroup of 230 (23%) with a prevalence of 26 (2.6%) CAS ≥50%. This subgroup contained 26 (72%) of the 36 plaques that produced a CAS ≥50%. A PACAS score ≥15 was able to identify a subgroup of 37 (3.7%) with a prevalence of 5 (13.5%) CAS ≥70%. PACAS scores of 0-4, 5-10, 11-14 and 15-20 identified four groups of 10-year observed ASCVD risk of 2% (low-risk), 13% (moderate-risk), 22% (high-risk) and 63% (very high- risk) respectively. The presence of two or more BWP could up classify 31 (14.5%) out of 225 in the low risk to the moderate risk group and 298 (48.2%) out of 619 subjects in the moderate risk group into a high-risk group. Conclusions: PACAS risk score performed well in the CESA cohort. It identified s ubgroups w ith a high prevalence of moderate and severe carotid artery stenosis. In addition, it identified four groups of 10-year risk of ASCVD: Low, moderate, high and very high risk. Modulation of this risk could be achieved by the number of bifurcations with plaque.