Echolucent Plaques Are Associated With High Risk of Ischemic Cerebrovascular Events in Carotid Stenosis

Abstract

Background-The purpose of the study was to assess in a prospective design whether plaque morphology is associated with risk of ischemic stroke and other cerebrovascular events in subjects with carotid stenosis. Methods and Results-A total of 223 subjects with carotid stenosis (123 with 35% to 49% degree of stenosis, 100 with 50% to 99% stenosis) and 215 control subjects matched by age and sex who participated in a population health survey at baseline were followed up for 3 years. Plaque echogenicity was assessed by ultrasound at baseline and scored as echolucent, predominantly echolucent, predominantly echogenic, or echogenic. Forty-four subjects experienced Ն1 ischemic cerebrovascular events in the follow-up period. Plaque echogenicity, degree of stenosis, and white blood cell count were independent predictors of cerebrovascular events. The unadjusted relative risk for cerebrovascular events was 13.0 (95% CI 4.5 to 37.4) in subjects with echolucent plaques and 3.7 (95% CI 0.7 to 18.2) in subjects with echogenic plaques when subjects without stenosis were used as the reference. The adjusted relative risk for cerebrovascular events in subjects with echolucent plaques was 4.6 (95% CI 1.1 to 18.9), and there was a significant linear trend (Pϭ0.015) for higher risk with increasing plaque echolucency. The adjusted relative risk for a 10% increase in the degree of stenosis was 1.2 (95% CI 1.04 to 1.4). Conclusions-Subjects with echolucent atherosclerotic plaques have increased risk of ischemic cerebrovascular events independent of degree of stenosis and cardiovascular risk factors. Subjects at high risk for ischemic vascular events may be identified by ultrasound assessment of plaque morphology.

Age dependency of ischaemic stroke subtypes and vascular risk factors in western Norway: the Bergen Norwegian Stroke Cooperation Study

“…Large‐artery atherosclerosis is classified according to rather rigid TOAST criteria, which requires occlusion or ≥50% stenosis in a related artery 7, not paying attention to atherosclerotic plaque instability which may lead to arterio‐arterial embolism even from stenosis of low or moderate degree 33, 34. Hence, true large‐artery atherosclerosis is in general likely to be underestimated due to an arbitrary TOAST definition.…”

Long-term treatment with low-dose metoprolol CR/XL is associated with increased plaque echogenicity: The Beta-blocker Cholesterol-lowering Asymptomatic Plaque Study (BCAPS)

“…Several lines of evidence suggest that this could possibly reflect a stabilizing effect on the lesion. Previous studies have shown that echogenic plaques have a more stable phenotype and are associated with a lower risk for development of clinical events [6,7].…”

“…The possibility to assess carotid plaque morphology in terms of echogenicity expressed as gray scale median (GSM) on ultrasound images has been explored during recent years. The results of these studies indicate that echolucent plaques are associated with an increased risk for ischemic cerebrovascular events independent of degree of stenosis [6,7]. Echolucent plaques have been shown to contain more lipids [8], macrophages [9], and elastin [10] in comparison to more echogenic lesions.…”

Carotid atherosclerotic plaque characterisation by measurement of ultrasound sound speed in vitro at high frequency, 20MHz

“…This evidence has been buoyed by the Tromsø study which followed up 223 patients with 35-99% stenosis and 215 controls for 3 years. It found that the RRs of ipsilateral cerebrovascular events for the predominantly echolucent and wholly echolucent groups were 3.5 (95% CI, 1.0 -12.4) and 3.6 (95% CI, 0.8 -16.8) respectively compared to the echogenic plaques (Mathiesen, Bonaa, & Joakimsen 2001). A further study (Grønholdt et al 2001) looked at the RR of ischaemic stroke, as opposed to cerebrovascular events, between the two groups and found it to be 3.1 (95% CI, 1.3 -7.3).…”