Assessment of the vulnerable carotid atherosclerotic plaque using contrast-enhanced ultrasonography

Factors Associated with High-Risk Plaque Characteristics Among Patients with Medium to Severe Carotid Artery Stenosis

BACKGROUND

There has been a large discussion in literature regarding the proper management of asymptomatic patients with significant carotid artery stenosis. This study aims to identify potential risk factors associated with high-risk carotid plaques.

METHODS

This is a retrospective study based on a prospective database. Eligible patients had medium to severe symptomatic or asymptomatic carotid stenosis (≥50%, North American Symptomatic Carotid Endarterectomy Trial criteria). This study will analyze patients recruited by our institution as part of the multicenter TAXINOMISIS project (NCT03495830). According to protocol, all patients underwent a colored Duplex ultrasound examination and a magnetic resonance angiography at baseline. Carotid plaques were classified according to Gray-Weale ultrasonographic criteria (types I-V). Main outcomes included the occurrence of symptoms, the high/low echogenicity of the plaque, the existence of intraplaque hemorrhage and the existence of lipidic/necrotic core. Secondary, risk factors associated with the aforementioned outcomes were evaluated.

RESULTS

A total of 62 patients (mean age: 68.7 ± 9.3 years, 66.1% males, 24.2% symptomatic) were recruited by our department. Mean carotid stenosis was 70.81% ± 13.53%. In multivariate regression analysis, C-reactive protein > 2 mg/l was strongly associated with symptomatic stenosis (odds ratio [OR] = 9.92 [1.12-88.178]; P = 0.039), and low high-density lipoprotein levels (<1200 mmol/l) were associated with lipidic/necrotic plaque core (OR = 16.88 [1.10-259.30]; P = 0.043). Low high-density lipoprotein levels (OR = 7.22 [1.00-51.95], P = 0.049) and HbA1c >7% (OR = 0.08 [0.01-0.93], P = 0.044) were associated with type III/IV plaques whereas HgAbc1 >7% (OR = 14.26 [1.21-168.34], P = 0.035) was associated with type V plaques.

CONCLUSIONS

This preliminary study has revealed some potential risk factors associated with unstable carotid plaques. These data could help the future development of prognostic models for early detection patients that could benefit from further intervention.

Pathological Intraplaque Hemorrhage as the Gold Standard to Assess the Efficacy of Ultrasound in Predicting Vulnerable Carotid Plaque Rupture

OBJECTIVE

To assess the clinical utility of ultrasound in predicting the risk of carotid vulnerable plaque rupture using pathological intraplaque hemorrhage as the gold standard.

METHODS

A total of 118 patients who underwent endarterectomy due to symptomatic carotid artery stenosis were enrolled. Conventional ultrasound assessed the plaque thickness, area stenosis rate, echo, and surface morphology. Neovascularization were assessed by contrast-enhanced ultrasound (CEUS) and tracing intraplaque nonenhanced areas. According to neovascularization grade (0-4), plaques were classified as low-, intermediate-, and high risk. Fresh intraplaque hemorrhage within the pathology was adopted as the gold standard for diagnosing plaque rupture risk. Thus, we divided patients into ruptured risk and nonruptured risk groups to assess the value of crucial factors for plaque rupture risk using ultrasound.

RESULTS

Of the 118 patients, hypertension accounted for 71.2%, hyperlipidemia 68.6%, diabetes 52.5%, and statin history 64.4%. In the rupture risk group, diabetes, smoking, and stenosis rate were significantly higher than the nonrupture risk group (P < .001); plaque thickness ≥4 mm (P > .05); and mainly hypoechoic with irregular surface morphology (P < .001), nonenhanced areas in the plaques (P < .001), and neovascularization >grade 2 (P < .001). Compared with the low-risk group, plaque rupture risk was 7.219 times higher in the medium-risk group and 18.333 times higher in the high-risk group. The kappa value of the interobserver consistency of crucial ultrasound parameters was >0.75, and the intraclass correlation coefficient was 0.919 (P < .01).

CONCLUSIONS

Both conventional ultrasound and CEUS have significant clinical importance in the prediction of rupture risk in vulnerable carotid plaques, thereby enabling stroke risk stratification and the assessment of plaque rupture risk.

Diagnostic Performance of Atherosclerotic Carotid Plaque Neovascularization with Contrast-Enhanced Ultrasound: A Meta-Analysis

Objectives

To evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) for atherosclerotic carotid plaque neovascularization.

Methods

The electronic databases like PubMed, Embase, OVID, and Web of Science were used to search for the relevant studies, which are involved in the evaluation of the diagnostic parameters of QUS for atherosclerotic carotid plaque neovascularization. Review Manager 5.4 and Stata 14.0 were used to estimate the pooled diagnostic value of CEUS. Forest plots, sensitivity analysis, and Deeks' funnel plots were performed on the included studies.

Results

Ten studies eventually met the final inclusion criteria. For diagnostic performance, CUES showed that the pooled values of sensitivity, specificity, positive likelihood odds ratios, negative likelihood odds ratios, and diagnostic odds ratios were 0.83 (95% CI 0.78-0.86), 0.77 (95% CI 0.68-0.84), 3.61 (95% CI 2.59-5.03), 0.23 (95% CI 0.18-0.28), and 16.02 (95% CI 10.02-25.60), respectively. The estimate of the area under curve (AUC) was 0.85 (95% CI 0.82-0.88).

Conclusion

Our research supported that CEUS had high sensitivity and specificity in the diagnosis of atherosclerotic carotid plaque neovascularization. More high-quality prospective multicenter studies focusing on the accuracy of CEUS for carotid atherosclerotic plaque should be performed to verify our conclusions.

Recent advances in vascular ultrasound imaging technology and their clinical implications

In this paper recent advances in vascular ultrasound imaging technology are discussed, including three-dimensional ultrasound (3DUS), contrast-enhanced ultrasound (CEUS) and strain- (SE) and shear-wave-elastography (SWE). 3DUS imaging allows visualisation of the actual 3D anatomy and more recently of flow, and assessment of geometrical, morphological and mechanical features in the carotid artery and the aorta. CEUS involves the use of microbubble contrast agents to estimate sensitive blood flow and neovascularisation (formation of new microvessels). Recent developments include the implementation of computerised tools for automated analysis and quantification of CEUS images, and the possibility to measure blood flow velocity in the aorta. SE, which yields anatomical maps of tissue strain, is increasingly being used to investigate the vulnerability of the carotid plaque, but is also promising for the coronary artery and the aorta. SWE relies on the generation of a shear wave by remote acoustic palpation and its acquisition by ultrafast imaging, and is useful for measuring arterial stiffness. Such advances in vascular ultrasound technology, with appropriate validation in clinical trials, could positively change current management of patients with vascular disease, and improve stratification of cardiovascular risk.

Neurovascular disease, diagnosis, and therapy: Cervical and intracranial atherosclerosis, vasculitis, and vasculopathy

Stroke is a leading cause of death, disability, and financial burden in the United States. Perhaps more than any other disease process, the rapidity with which the diagnosis and treatment of stroke are successfully achieved is paramount to the reduction of its associated morbidity and mortality. Steno-occlusive intracranial vascular disease, the most notorious culprit of cerebral ischemia and/or hemorrhage, traces its etiology to native and embolic atherosclerosis as well as various forms of vascular inflammation, insult, and dysfunction. Distinguishing between these causes is a critical first step in the diagnosis and treatment of a patient presenting with cerebrovascular compromise. In this chapter, we delineate the clinical and imaging features of cervical and intracranial atherosclerosis, vasculitis, and vasculopathy, along with the evidence behind the treatments which comprise their current-day standard of care. The modern imaging armamentarium is diverse and complex, with contrast-enhanced and non-contrast MR angiography, CT angiography, digital subtraction angiography, and ultrasound; each playing an important role in providing rapid insight into the patient's disease process. Understanding these imaging techniques and their application in the acute setting is critical for the provider caring for stroke patients.

Association Between Serum Apolipoprotein A1 Levels, Ischemic Stroke Subtypes and Plaque Properties of the Carotid Artery

Background

This study aimed to investigate the association between serum apolipoprotein A1 (ApoA1) levels, ischemic stroke subtypes and plaque properties.

Methods

We enrolled 92 patients with ischemic stroke and 21 age-matched controls (CONT). The stroke patients were divided into three subtypes: cardioembolic (CE, n = 15), atherothrombotic infraction (ATBI, n = 52), and lacunar infarction (LI, n = 25). Carotid plaques were classified as low, intermediate, or high intensity, and either simple or mixed type. Serum lipids (total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG)), ApoA1, and ApoB were analyzed using commercially available kits.

Results

There was no difference in TC, LDL-C, HDL-C, and ApoB levels among the four groups. Serum ApoA1 levels in the ATBI group were significantly lower compared with the CONT group. Among the ATBI group, the serum ApoA1 levels in the low-intensity plaque-type were significantly lower than those in the intermediate or hard-intensity plaque-type. Furthermore, serum ApoA1 levels in the mixed plaque-type were significantly lower than those in the simple type.

Conclusions

These findings suggest that serum ApoA1 levels might be associated with the development of ATBI and plaque properties of the carotid artery.

Characteristics of the carotid plaque in hypertensive patients with hyperhomocysteinemia using multimode ultrasound

BACKGROUND

Ischemic stroke is related to the level of total homocysteine and the stability of carotid atherosclerotic plaque. In this study, the characteristics of carotid plaque in hypertensive patients with hyperhomocysteinemia were preliminarily studied by conventional ultrasound, contrast-enhanced ultrasound and virtual touch image quantification.

METHODS

Hypertensive patients (n=196) hospitalised in the Department of Neurology and Cardiology of our hospital from April 2016 to February 2019 were studied to compare and analyse differences in general clinical data, conventional ultrasound, contrast-enhanced ultrasound and virtual touch image quantification between hypertension with hyperhomocysteinemia and hypertension with normal tHcy.

RESULTS

1. There was no statistical difference in other clinical data, except fasting blood sugar (P=0.021) and the history of cerebral infarction (P=0.0001). 2. There were significant differences in plaque thickness, stenosis degree, contrast-enhanced ultrasound level, The maximum shear wave velocity (SWVmax) , the minimum shear wave velocity (SWVmin) and the mean shear wave velocity (SWVmean) (P<0.05), except intima-media thickness between the two groups (t=0.160, P=0.873). 3. Blood tHcy level in hypertensive patients with hyperhomocysteinemia was positively correlated with carotid plaque thickness, stenosis degree and contrast-enhanced ultrasound level (r=0.349, 0.647, 0.421), but negatively correlated with SWVmax, SWVmin and SWVmean (r=-0.348, -0.409, -0.393).

CONCLUSIONS

Ultrasonography can reflect the vulnerability of hypertensive patients with hyperhomocysteinemia, providing reliable and comprehensive information for the prevention and treatment of stroke in hypertensive patients with hyperhomocysteinemia.

The Role of Contrast-Enhanced Ultrasound in Managing Vascular Pathologies

INTRODUCTION

Ultrasound is a useful first-line imaging modality for diagnosing and monitoring vascular pathologies. Compared with other modalities, it is relatively low cost, requires no ionizing radiation, is often available at bedside, and is noninvasive. However, the modality can have limitations when differentiating normal from pathologic tissues. In this review, we discuss the role of contrast-enhanced ultrasound (CEUS) in carotid, aortic, and peripheral vascular conditions.

DISCUSSION

CEUS is a developing modality that supersedes standard vascular ultrasound imaging and complements other modalities such as computed topography and magnetic resonance angiograms. Administered intravenously, the contrast are microbubbles filled with gas, surrounded by a stabilizing shell. They have the ability to enhance the quality of images and quantify vascular pathologies by acting as intravascular tracers of ultrasound energy. Based on these properties, CEUS has the potential to play a pivotal role in the management of vascular pathologies through its utility in detection, diagnosis, risk-stratification, follow-up, and monitoring.

CONCLUSION

Studies have suggested that CEUS is superior compared with standard ultrasound and on-par with computed topography angiograms in the detection of vascular pathologies, concluding that CEUS should be part of standardized routine practice.

Monocyte and Macrophage Dynamics in the Cardiovascular System: JACC Macrophage in CVD Series (Part 3)

It has long been recognized that the bone marrow is the primary site of origin for circulating monocytes that may later become macrophages in atherosclerotic lesions. However, only in recent times has the complex relationship among the bone marrow, monocytes/macrophages, and atherosclerotic plaques begun to be understood. Moreover, the systemic nature of these interactions, which also involves additional compartments such as extramedullary hematopoietic sites (i.e., spleen), is only just becoming apparent. In parallel, progressive advances in imaging and cell labeling techniques have opened new opportunities for in vivo imaging of monocyte/macrophage trafficking in atherosclerotic lesions and at the systemic level. In this Part 3 of a 4-part review series covering the macrophage in cardiovascular disease, the authors intersect systemic biology with advanced imaging techniques to explore monocyte and macrophage dynamics in the cardiovascular system, with an emphasis on how events at the systemic level might affect local atherosclerotic plaque biology.

Contrast-enhanced ultrasonography for assessing neovascularization of carotid atherosclerotic plaque

Neovascularization of a carotid atherosclerotic plaque (AP) is associated with an increased risk of stroke. Contrast-enhanced ultrasonography (CEUS) is a widely used method for imaging intraplaque neovascularization in vivo. Unfortunately, there are no standardized guidelines for CEUS interpretation. The aim of this study was to identify the most reliable method for CEUS-based assessment of AP neovascularization. Seventy-eight AP were removed during carotid endarterectomy in 73 patients, of whom 5 had AP on both sides, and examined morphologically. All patients underwent preoperative duplex scanning and CEUS; Sonovue was used as a contrast agent. AP neovascularization was assessed on a 4-grade visual scale and with 3 different quantitative methods using QLAB software. On the visual scale (method 1), poorly (37%) and moderately (51%) vascularized plaques were the most common. Quantitative analysis (data were presented as Me (Q1; Q3)) revealed that the number of blood vessels per 1 cm2 of the plaque (method 2) was 16 (10; 26), the ratio of the total vessel area to the plaque area (method 3) was 6% (3; 9), and AP ROI (method 4) was 2.6 dB (1.8; 4.1). Significant correlations were demonstrated between the results produced by method 2 and method 3 (р < 0.0001), method 3 and method 2 (p = 0.0006), and between pathomorphological findings and the results produced by methods 1–3, especially method 2 (p < 0.004). AP ROI brightness did not correlate with other results. The presence of hyperechoic components (calcifications) in AP dramatically reduced the reliability of US-based intraplaque neovascularization assessment. The most accurate CEUS-based quantitative method for assessing intraplaque neovascularization is estimation of blood vessel number per 1 cm2 of the plaque.

Invasive treatment in peripheral artery disease

Invasive treatment in peripheral artery disease (PAD) has evolved as a viable alternative to surgical treatment. However, beyond the common pathophysiological substrate, as far as treatment is concerned, each site of atherosclerotic disease (subclavian and vertebral arteries; carotid arteries; intracranial arterial tree; renal arteries; lower extremity arteries) features unique characteristics. Treatment options include medical treatment, endovascular management and/or surgery. Sound clinical evaluation is required as individual patient assessment often limits intervention options, while available data regarding benefits of invasive and surgical management are questioned by advances in medical treatment. In the present article, we aim to summarize existing evidence and guidance on the role of invasive procedures in PAD.

Late Sac Rupture due to a Type IV Endoleak after Previous Endovascular Aortic Aneurysm Repair: A Case Report

Type IV endoleaks have been identified as endoleaks of low flow, and rupture risk has been estimated to be minimal in literature. Therefore, conservative treatment has been recommended in most cases. We are presenting a rare case of late rupture due to type IV endoleak that was treated with open repair applying a novel surgical technique.

Lectin Pathway of Complement Activation Is Associated with Vulnerability of Atherosclerotic Plaques

Inflammatory mechanisms may be involved in atherosclerotic plaque rupture. By using a novel histology-based method to quantify plaque instability here, we assess whether lectin pathway (LP) of complement activation, a major inflammation arm, could represent an index of plaque instability. Plaques from 42 consecutive patients undergoing carotid endarterectomy were stained with hematoxylin-eosin and the lipid core, cholesterol clefts, hemorrhagic content, thickness of tunica media, and intima, including or not infiltration of cellular debris and cholesterol, were determined. The presence of ficolin-1, -2, and -3 and mannose-binding lectin (MBL), LP initiators, was assessed in the plaques by immunofluorescence and in plasma by ELISA. LP activation was assessed in plasma by functional in vitro assays. Patients presenting low stenosis (≤75%) had higher hemorrhagic content than those with high stenosis (>75%), indicating increased erosion. Increased hemorrhagic content and tunica media thickness, as well as decreased lipid core and infiltrated content were associated with vulnerable plaques and therefore used to establish a plaque vulnerability score that allowed to classify patients according to plaque vulnerability. Ficolins and MBL were found both in plaques’ necrotic core and tunica media. Patients with vulnerable plaques showed decreased plasma levels and intraplaque deposition of ficolin-2. Symptomatic patients experiencing a transient ischemic attack had lower plasma levels of ficolin-1. We show that the LP initiators are present within the plaques and their circulating levels change in atherosclerotic patients. In particular, we show that decreased ficolin-2 levels are associated with rupture-prone vulnerable plaques, indicating its potential use as marker for cardiovascular risk assessment in atherosclerotic patients.