Relationship between Plaque Echo, Thickness and Neovascularization Assessed by Quantitative and Semi-quantitative Contrast-Enhanced Ultrasonography in Different Stenosis Groups

Carotid Intraplaque Neovascularization Predicts Ischemic Stroke Recurrence in Patients with Carotid Atherosclerosis

INTRODUCTION

This study aimed to examine whether intraplaque neovascularization (IPN) of carotid plaques, as characterized by contrast-enhanced ultrasound (CEUS), is associated with ischemic stroke recurrence in patients with carotid atherosclerosis.

METHODS

We conducted a prospective study of consecutive patients with a recent stroke and at least one atherosclerotic plaque in the carotid artery on the side consistent with symptoms. All patients underwent CEUS after their first admission. IPN was graded on the basis of the presence and location of microbubbles within each plaque.

RESULTS

We eventually included 155 patients, all of whom underwent IPN analysis. After a follow-up of 24 months, we recorded 25 (16.1%) stroke recurrences in the whole population. All the recurrences occurred in patients presenting IPN. There was significant difference in the IPN between the 2 groups (p = 0.002). In the final Cox proportional-hazards multivariable models, IPN of grade 2 was independently associated with the risk of stroke recurrence (HR = 4.535; 95% CI: 1.892-10.870; p = 0.001). This association remained after adjusting for the degree of carotid stenosis (HR = 3.491; 95% CI: 1.410-8.646; p = 0.007).

CONCLUSIONS

IPN was an independent predictor of stroke recurrence in patients with a recent ischemic stroke and carotid atherosclerosis. In predicting stroke recurrence, IPN may be an earlier indicator than carotid stenosis and may help stratify the risk of stroke recurrence.

Carotid intraplaque neovascularization predicts atherosclerotic renal artery stenosis in patients with carotid artery stenosis

BACKGROUND AND AIMS

This study aimed to examine whether intraplaque neovascularization (IPN) of carotid plaques, as characterized by contrast-enhanced ultrasound (CEUS), is associated with atherosclerotic renal artery stenosis (ARAS) in patients with normal kidney function.

METHODS AND RESULTS

We investigated carotid IPN using CEUS in 198 consecutive patients with normal kidney function with and without ARAS. IPN was graded on the basis of the presence and location of microbubbles within each plaque (0, no visible microbubbles in the plaque; 1, moderate microbubbles confined to the shoulder and/or adventitial side of the plaque; and 2, extensive microbubbles throughout the plaque). The grades of each plaque were averaged to obtain an overall score per patient. ARAS was determined angiographically. We found that a higher CEUS-assessed carotid IPN score was associated with ARAS (Odd Ratio, OR: 7.281; 95% Confidence Interval, 95% CI: 3.246-16.336; P < 0.001). Furthermore, an IPN score >1.75 predicted severe stenosis with a sensitivity of 81% and specificity of 58%. Compared with using the IPN score alone, the addition of the homocysteine (HCY) cutoff value (>22.5 mmol/L) resulted in a stronger predictive value (Area Under Curve, AUC: 0.893 vs 0.834; P < 0.001) for severe ARAS.

CONCLUSION

Carotid plaque neovascularization combined with HCY levels is predictive of severe ARAS in patients with normal kidney function. CEUS-assessed carotid IPN is clinically useful for stratification of ARAS in patients with normal kidney function.

Contrast-Enhanced Ultrasound to Assess Carotid Intraplaque Neovascularization

Contrast-enhanced ultrasound (CEUS) is increasingly being used to identify patients with carotid plaques that are vulnerable to rupture, so-called vulnerable atherosclerotic plaques, by assessment of intraplaque neovascularization. A complete overview of the strengths and limitations of carotid CEUS is currently not available. The aim of this systematic review was to provide a complete overview of existing publications on the role of CEUS in assessment of carotid intraplaque neovascularization. The systematic review of the literature yielded 52 studies including a total of 4660 patients (mean age: 66 y, 71% male) who underwent CEUS for the assessment of intraplaque neovascularization. The majority of the patients (76%) were asymptomatic and had no history of transient ischemic attack (TIA) or stroke. The assessment of intraplaque neovascularization was mostly performed using a visual scoring system; several studies used time-intensity curves or dedicated quantification software to optimize analysis. In 17 studies CEUS was performed in patients before carotid surgery (endarterectomy), allowing a comparison of pre-operative CEUS findings with histologic analysis of the tissue sample that is removed from the carotid artery. In a total of 576 patients, the CEUS findings were compared with histopathological analysis of the plaque after surgery. In 16 of the 17 studies, contrast enhancement was found to correlate with the presence and degree of intraplaque neovascularization on histology. Plaques with a larger amount of contrast enhancement had significantly increased density of microvessels in the corresponding region on histology. In conclusion, CEUS is a readily available imaging modality for the assessment of patients with carotid atherosclerosis, providing information on atherosclerotic plaques, such as ulceration and intraplaque neovascularization, which may be clinically relevant. The ultimate clinical goal is the early identification of carotid atherosclerosis to start early preventive therapy and prevent clinical complications such as TIA and stroke.

Contrast-enhanced ultrasound perfusion patterns and serum lipid signatures of vulnerable carotid artery plaque in predicting stroke: A cohort study of carotid stenosis in Chinese patients

BACKGROUND

Early identification of vulnerable plaques at risk of rupture could help prevent cerebral ischemic stroke in patients with carotid artery disease.

OBJECTIVE

To investigate the correlation between contrast-enhanced ultrasound (CEUS) perfusion patterns and serum lipid signatures of carotid artery plaques with the degree of carotid stenosis.

METHODS

A total of 80 patients with carotid artery plaques who underwent CEUS were included. All patients underwent CEUS, computed tomography angiography or digital subtraction angiography, and serum lipid testing.

RESULTS

The contrast agent enhancement levels and the CEUS perfusion patterns in the plaques were associated with the degree of carotid stenosis (P < 0.05). Serum free fatty acid (FFA) was associated with the contrast agent enhancement levels (P < 0.05), but did not correlate with the degree of stenosis (P > 0.05). There was no significant difference in total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides with respect to contrast agent enhancement levels (P > 0.05) or the degree of stenosis (P > 0.05).

CONCLUSION

A high level of CEUS perfusion and increased serum FFA levels are indicative of vulnerable carotid plaques, which may be useful for the prediction of stroke in patients with carotid artery disease.

Assessment of Carotid Intraplaque Neovascularization Using Superb Microvascular Imaging in High Risk of Stroke Individuals: Results From a Community-Based Study

Background: Improved stroke risk stratification may improve stroke prevention. We aimed to study the value of a novel Doppler method, superb microvascular imaging (SMI), in correlating plaque thickness and evidence of intra-plaque neovascularization with a history stroke and TIA involving any cerebrovascular territory among community residents considered at high stroke risk.

Methods: We selected residents aged at least 40 years from the Donghuashi community in China who had at least three stroke risk factors (including a history of stroke or TIA) and carotid plaque thickness of at least 1.5 mm (but without heavy calcification) and no history of carotid endarterectomy or stenting. In this cross-sectional study, each subject underwent carotid plaque examination with standard ultrasound and SMI. SMI evidence of plaque neovascularization was categorized as none or mild (Grade 1) or moderate or marked (Grade 2) and correlated with past history of stroke or TIA.

Results: A total of 131 individuals (mean age 69 ± 8 years, 63% male) met the study inclusion criteria. SMI revealed no or mild neovascularization in 74 subjects (56.5%) and moderate or marked neovascularization in 57 subjects (43.5%). Subjects with moderate or marked neovascularization were more likely to have a history of any territory stroke or TIA, 43.9 vs. 17.6% (P = 0.001). Multivariate logistic regression analyses showed a thicker plaque (odds ratio: 2.272, 95% CI: 1.351–3.822, P = 0.002) and a history of stroke or TIA (odds ratio: 4.017, 95% CI: 1.719–9.387, P = 0.001) significantly correlated with evidence of moderate to marked intra-plaque neovascularization.

Conclusions: Moderate to marked intraplaque neovascularization detected by SMI was more likely in subjects with a history of any territory stroke or TIA or thicker plaque. This indicates a potential new role of SMI in stratifying future risk of stroke or other arterial disease complications.

Correlation between of small dense low-density lipoprotein cholesterol with acute cerebral infarction and carotid atherosclerotic plaque stability

Background

Acute cerebral infarction (ACI) is seriously harmful to human health worldwide. However, at present, the risk of disease onset is still not accurately predicted for some people.

Methods

Five hundred and nineteen patients with ACI and 300 healthy controls were included in this study. We divided the patients into three groups according to the results of cervical artery contrast‐enhanced ultrasound. Ninety‐five patients were in the CAS without plaque group, 108 patients were in the stable plaque group, and 316 patients were in the unstable plaque group. TC, TG, HDL‐C, LDL‐C, and sdLDL‐C were measured in all subjects.

Results

The level of small dense low‐density lipoprotein cholesterol (sdLDL‐C) in the ACI group was significantly higher than that in the control group (P < 0.001). Logistic regression analysis showed that sdLDL‐C was an independent risk factor for ACI (OR = 1.067, 95% CI: 1.041‐1.093, P < 0.001); serum sdLDL‐C was significantly higher in the unstable plaque group than in the stable plaque group and plaque‐free group (P < 0.05, P < 0.001); serum sdLDL‐C was also higher in the stable plaque group than the plaque‐free group (P < 0.001). Logistic regression analysis showed that sdLDL‐C was an independent risk factor for unstable carotid plaques (OR = 1.053, 95% CI: 1.038‐1.068, P < 0.001); Spearman correlation analysis showed that sdLDL‐C test results were positively correlated with carotid plaque stability (r = 0.363, P < 0.001).

Conclusion

Small dense low‐density lipoprotein cholesterol is an independent risk factor for the onset of ACI and may be an early serum marker for this disease.

Impact of Cardiovascular Risk Factors and Pharmacologic Treatments on Carotid Intraplaque Neovascularization Detected by Contrast-Enhanced Ultrasound

BACKGROUND

Neovascularization is a marker of plaque vulnerability that can be assessed noninvasively using contrast-enhanced ultrasound (CEUS). The presence and extent of plaque neovascularization and their relation to cardiovascular risk factors and treatments were assessed in asymptomatic patients with carotid stenosis of intermediate severity and no indication for revascularization.

METHODS

Sixty-six patients aged 69 ± 8 years (59% men) were prospectively enrolled. Plaque neovascularization was assessed using CEUS with sulfur hexafluoride contrast in each of the four carotid segments bilaterally (a total of 528 segments). In each plaque, the presence or absence of contrast enhancement was assessed semiquantitatively as CEUS grade 1 (no signal or signal confined to the adventitia and/or shoulder of the plaque) or CEUS grade 2 (signal within the plaque).

RESULTS

Plaques were detectable in 289 of 528 carotid segments (54.7%). CEUS grade 2 was present in at least one plaque in 48 of 66 patients (72.7%) and was not influenced by stenosis severity or morphology. The highest CEUS grade 2 prevalence was observed in patients with diabetes and the lowest in those treated with angiotensin-converting enzyme inhibitors and statins, especially when low-density lipoprotein cholesterol was <100 mg/dL. Patients with multiple CEUS grade 2 plaques (20 of 66 [30%]) had both higher low-density lipoprotein and higher C-reactive protein.

CONCLUSION

Intraplaque neovascularization is frequent in asymptomatic patients with intermediate carotid stenosis and is more prevalent in those with diabetes. Low-density lipoprotein cholesterol < 100 mg/dL and treatment with angiotensin-converting enzyme inhibitors seem to confer protection from neovascularization, although larger interventional studies are necessary to confirm these data.

Contrast Enhanced Ultrasound (CEUS) Is Not Able to Identify Vulnerable Plaques in Asymptomatic Carotid Atherosclerotic Disease

OBJECTIVES

Contrast enhanced ultrasound (CEUS) has been suggested as an imaging tool for detection of asymptomatic carotid atherosclerotic disease (ACAD) at high risk of cerebral embolisation. The objective of this study was to evaluate CEUS and immunohistochemical (IHC) patterns in ACAD (i.e., without any neurologic symptoms in the last 6 months) and their correlations with histology.

METHODS

CEUS analysis was classified on a semiquantitative basis using a three-point classification scale. Plaque morphology was assessed using the American Heart Association (AHA) classification of atherosclerotic plaques, then accordingly assigned as non-vulnerable (AHA Type IV/V) or vulnerable (AHA Type VI). IHC analysis for intra-plaque neo-angiogenesis (IPN) was identified by CD34/VEGF immunostaining and classified on a semiquantitative basis using a four-point classification scale. Both CEUS and IHC analyses were performed and scored by single observers.

RESULTS

Fifty-eight consecutive asymptomatic patients (mean age 73 years, 33 males) undergoing carotid endarterectomy were included in the final analysis. Nineteen had AHA Class IV/V plaques, and the remaining 39 had AHA Class VI plaques. There were two main findings of the study: (a) histologically proven vulnerable plaques compared with histologically proven non-vulnerable plaques had denser IPN (p = .004), but did not show more pronounced contrast enhancement; (b) the correlation between IHC analysis and CEUS analysis was significant for both vulnerable and non-vulnerable plaques (p = .04 and p = .01, respectively), but it was direct for AHA Type IV/V plaques and inverse for AHA Type VI plaques.

CONCLUSIONS

The main findings of the study were that histologically proven vulnerable plaques (i.e., AHA Class VI) as compared with histologically proven non-vulnerable plaques (i.e., AHA Class IV/V) had denser neo-vascularisation, but not more pronounced contrast enhancement.