LAUSR

By use of magnetic resonance imaging (MRI), Xin et al compared plaque characteristics between symptomatic and asymptomatic sides in patients with bilateral vulnerable carotid plaques. Vulnerable plaques demonstrated greater plaque burden, a larger lipid-rich necrotic core/fibrous cap rupture and intraplaque hemorrhage volume, and more juxtaluminal intraplaque hemorrhage/fibrous cap rupture and/or thrombus compared with asymptomatic plaques. The authors concluded that plaques with greater plaque burden and more vulnerable features are at higher risk of cerebrovascular symptoms. Some additional comments may be of interest. An earlier study evaluated carotid plaques using computed tomography angiography (CTA) in symptomatic patients with bilateral intraplaque hemorrhage (n 1⁄4 343). Volume measurement, intraplaque hemorrhage volume, and percentage were larger in the carotid plaques on the symptomatic side compared with the asymptomatic one. Nevertheless, a limitation of both studies is that in patients with a “symptomatic” and a contralateral “asymptomatic” side there are confounding factors due to the arterial anastomoses in the Circle of Willis. The authors support the use of MRI as the imaging modality of choice for carotid atherosclerosis. Although MRI has considerable advantages as discussed by the authors (eg, detection of plaque burden, fibrous cap rupture, juxtaluminal intraplaque hemorrhage, and/or thrombus), it has a high cost and is not widely available. A recent multinational survey of current carotid imaging practice reported that Duplex ultrasound is the first examination used to evaluate and characterize the carotid atherosclerotic disease, followed by CTA and then MRI. Computed tomography angiography is a quicker and more cost-effective imaging technique thanMRI and may identify vulnerable carotid plaque features with similar sensitivity and specificity as MRI. European and US guidelines for the prevention of stroke in patients with carotid stenosis base their recommendations on quantification of the percentage reduction in luminal diameter due to the atherosclerotic process. Although this is a widely established classification, it is becoming clear that a better classification is required as some subtypes of carotid plaque (eg, vulnerable plaques) can predict the occurrence of stroke independent of the degree of stenosis. Moreover, it is useful to remember that the “degree of stenosis” is the indirect representation of plaque burden and it was the leading parameter for the choice of therapeutic options because when the cornerstone randomized controlled trials were performed in the 1980s, the North American Symptomatic Carotid Endarterectomy Trial and the European Carotid Surgery Trial, it was the only imaging option to study carotid arteries in vivo. Due to advances in imaging techniques, it has become possible to move beyond the luminographic representation of the carotid and routinely detect and characterize the specific features of plaque vulnerability, such as intraplaque hemorrhage, thrombus, carotid plaque volume, neovascularization, and inflammation. These promising biomarkers could change current management strategies based on the degree of stenosis. The 2018 European Society for Vascular Surgery recognized that certain plaque characteristics are associated with an increased risk of future stroke in patients with asymptomatic carotid stenosis (ACS). These features included juxtaluminal black area on computerized plaque analysis, intraplaque hemorrhage on MRI, plaque echolucency on Duplex ultrasound, and spontaneous embolization on transcranial Doppler ultrasound alone or in addition to uniformly or predominantly echolucent plaques (Table 1). It was recommended that in “average surgical risk” patients with a 60% to 99% ACS, carotid endarterectomy (CEA) should be considered in the presence of �1 imaging characteristics that may be associated with an increased risk of late ipsilateral stroke, provided documented perioperative stroke/death rates are <3% and the patient’s