Association between intraplaque neovascularization assessed by contrast-enhanced ultrasound and the risk of stroke

Added Clinical Value of Intraplaque Neovascularization Detection to Color Doppler Ultrasound for Assessing Ischemic Stroke Risk

Purpose

Intraplaque neovascularization, assessed using contrast-enhanced ultrasound (CEUS), is associated with ischemic stroke. It remains unclear whether detection of intraplaque neovascularization combined with color Doppler ultrasound (CDUS) provides additional value compared with CDUS alone in assessing ischemic stroke risk. Therefore, we investigated the clinical value of combined CEUS, CDUS, and clinical features for ischemic stroke risk stratification.

Patients and Methods

We recruited 360 patients with ≥50% carotid stenosis between January 2019 and September 2022. Patients were examined using CDUS and CEUS. Covariates associated with ischemic stroke were identified using multivariate logistic regression analysis. The discrimination and calibration were verified using the C-statistic and Hosmer-Lemeshow test. The incremental value of intraplaque neovascularization in the assessment of ischemic stroke was analyzed using the Delong test.

Results

We analyzed the data of 162 symptomatic and 159 asymptomatic patients who satisfied the inclusion and exclusion criteria, respectively. Based on multivariate logistic regression analysis, we constructed a nomogram using intraplaque neovascularization, degree of carotid stenosis, plaque hypoechoicity, and smoking status, with a C-statistic of 0.719 (95% confidence interval [CI]: 0.666-0.768) and a Hosmer-Lemeshow test p value of 0.261. The net reclassification index of the nomogram was 0.249 (95% CI: 0.138-0.359), and the integrated discrimination improvement was 0.053 (95% CI: 0.029-0.079). Adding intraplaque neovascularization to the combination of CDUS and clinical features (0.672; 95% CI: 0.617-0.723) increased the C-statistics (p=0.028).

Conclusion

Further assessment of intraplaque neovascularization after CDUS may help more accurately identify patients at risk of ischemic stroke. Combining multiparametric carotid ultrasound and clinical features may help improve the risk stratification of patients with ischemic stroke with ≥50% carotid stenosis.

Carotid plaque score and ischemic stroke risk stratification through a combination of B-mode and contrast-enhanced ultrasound in patients with low and intermediate carotid stenosis

Objective

The occurrence of ischemic stroke (IS) is closely related to the characteristics of carotid plaque (CP). Due to the effect of stroke risk stratification based on B-mode ultrasound (US) and contrast-enhanced ultrasound (CEUS) that has not been studied in patients with low and intermediate carotid stenosis, we construct and validate a CP score and ischemic stroke risk stratification (ISRS) using a combination of B-mode and CEUS, in order to provide new convenient strategies to stratify these patients to prevent stroke.

Materials and methods

This retrospective study evaluated 705 patients with low and intermediate carotid stenosis who underwent B-mode and CEUS from November 2021 to April 2023. Qualitative B-mode and CEUS features of carotid plaques were analyzed using a univariable and multivariable logistic regression to construct the CP score. Then, we combined the CP score with Essen stroke risk score (ESRS) to develop ISRS.

Results

This study included a total of 705 patients with low and intermediate carotid stenosis, of which 394 were symptomatic patients (with a mean age of 71.03 ± 10.48 years) and 311 were asymptomatic patients (with a mean age of 65.13 ± 10.31 years). Plaque echogenicity, plaque morphology, carotid intima-media thickness in B-mode US and intraplaque neovascularization grading and perfusion pattern in CEUS were significantly associated with IS. The ISRS incorporating these five predictors and ESRS showed good discrimination and calibration in both primary cohort [area under the curve (AUC), 0.91; Hosmer-Lemeshow test, p = 0.903] and validation cohort (AUC, 0.84; Hosmer-Lemeshow test, p = 0.886).

Conclusion

We developed an effective and practical tool to identify and stratify patients with low and intermediate carotid stenosis, based on the CP score and ISRS estimation. Our study may provide new insights into managing patients with no indication of surgery.

Value of Intraplaque Neovascularization on Contrast-Enhanced Ultrasonography in Predicting Ischemic Stroke Recurrence in Patients With Carotid Atherosclerotic Plaque

OBJECTIVE

Patients with a history of ischemic stroke are at risk for a second ischemic stroke. This study aimed to investigate the relationship between carotid plaque enhancement on perfluorobutane microbubble contrast-enhanced ultrasonography (CEUS) and future recurrent stroke, and to determine whether plaque enhancement can contribute to risk assessment for recurrent stroke compared with the Essen Stroke Risk Score (ESRS).

MATERIALS AND METHODS

This prospective study screened 151 patients with recent ischemic stroke and carotid atherosclerotic plaques at our hospital between August 2020 and December 2020. A total of 149 eligible patients underwent carotid CEUS, and 130 patients who were followed up for 15-27 months or until stroke recurrence were analyzed. Plaque enhancement on CEUS was investigated as a possible risk factor for stroke recurrence and as a possible adjunct to ESRS.

RESULTS

During follow-up, 25 patients (19.2%) experienced recurrent stroke. Patients with plaque enhancement on CEUS had an increased risk of stroke recurrence events (22/73, 30.1%) compared to those without plaque enhancement (3/57, 5.3%), with an adjusted hazard ratio (HR) of 38.264 (95% confidence interval [CI]:14.975-97.767; P < 0.001) according to a multivariable Cox proportional hazards model analysis, indicating that the presence of carotid plaque enhancement was a significant independent predictor of recurrent stroke. When plaque enhancement was added to the ESRS, the HR for stroke recurrence in the high-risk group compared to that in the low-risk group (2.188; 95% CI, 0.025-3.388) was greater than that of the ESRS alone (1.706; 95% CI, 0.810-9.014). A net of 32.0% of the recurrence group was reclassified upward appropriately by the addition of plaque enhancement to the ESRS.

CONCLUSION

Carotid plaque enhancement was a significant and independent predictor of stroke recurrence in patients with ischemic stroke. Furthermore, the addition of plaque enhancement improved the risk stratification capability of the ESRS.

Effect of evolocumab on the progression of intraplaque neovascularization of the carotid based on contrast-enhanced ultrasonography (EPIC study): A prospective single-arm, open-label study

Background and Purpose: The aim of this study was to explore the effect of half a year of evolocumab plus moderate-intensity statin treatment on carotid intraplaque neovascularization (IPN) and blood lipid levels. Methods: A total of 31 patients with 33 carotid plaques who received evolocumab plus statin treatment were included. Blood lipid levels, B-mode ultrasound and contrast-enhanced ultrasonography (CEUS) at baseline and after half a year of evolocumab plus statin therapy were collected. The area under the curve (AUC) reflected the total amount of acoustic developer entering the plaque or lumen within the 180 s measurement period. The enhanced intensity reflected the peak blood flow intensity during the monitoring period, and the contrast agent area reflected the area of vessels in the plaques. Results: Except for high-density lipoprotein cholesterol (HDL-c), all other lipid indices decreased. Compared with baseline, low-density lipoprotein cholesterol (LDL-c) decreased by approximately 57% (p < 0.001); total cholesterol (TC) decreased by approximately 34% (p < 0.001); small dense low-density lipoprotein (sd-LDL) decreased by approximately 52% (p < 0.001); and HDL-c increased by approximately 20% (p < 0.001). B-mode ultrasonography showed that the length and thickness of the plaque and the hypoechoic area ratio were reduced (p < 0.05). The plaque area, calcified area ratio, and lumen cross-sectional area changed little (p > 0.05). CEUS revealed that the area under the curve of plaque/lumen [AUC (P/L)] decreased from 0.27 ± 0.13 to 0.19 ± 0.11 (p < 0.001). The enhanced intensity ratio of plaque/lumen [intensity ratio (P/L)] decreased from 0.37 ± 0.16 to 0.31 ± 0.14 (p = 0.009). The contrast agent area in plaque/area of plaque decreased from 19.20 ± 13.23 to 12.66 ± 9.59 (p = 0.003). The neovascularization score decreased from 2.64 ± 0.54 to 2.06 ± 0.86 (p < 0.001). Subgroup analysis based on statin duration (<6 months and ≥6 months) showed that there was no significant difference in the AUC (P/L) or intensity ratio (P/L) at baseline or after half a year of evolocumab treatment. Conclusion: This study found that evolocumab combined with moderate-intensity statins significantly improved the blood lipid profile and reduced carotid IPN. Clinical Trial Registration: https://www.clinicaltrials.gov; identifier: NCT04423406.

Contrast-enhanced ultrasound for the evaluation of symptomatic and asymptomatic carotid plaques: A systematic review and meta-analysis

BACKGROUND

Contrast-enhanced ultrasound (CEUS) is a promising imaging modality for the assessment of plaque vulnerability. We aimed to systematically review and meta-analyze the ability of CEUS parameters to differentiate between symptomatic and asymptomatic carotid plaques and to assess its reproducibility.

METHODS

PubMed, EMBASE, and Cochrane Library databases were searched for studies that potentially evaluated carotid plaques using CEUS. From the initial 2870 searches, 11 relevant publications comprising a total of 821 carotid plaques were reviewed. Data on CEUS parameters including quantitative and semi-quantitative parameters were extracted and analyzed.

RESULTS

The overall analysis showed significantly higher CEUS parameters in symptomatic carotid plaques compared to asymptomatic carotid plaques (standardised mean difference (SMD) .95, 95% confidence interval (CI) .56-1.27, p < .01). Intra and inter-observer reproducibility of quantitative CEUS parameters were excellent (intra-observer, r = .95, 95% CI .87-1; inter-observer, r = .93, 95% CI .80-.1). Semi-quantitative CEUS parameters showed good intra-observer reliability and moderate inter-observer reliability (intra-observer, r = .77, 95% CI .64-.89; inter-observer, r = .75, 95% CI .61-.89). Heterogeneity among studies compared CEUS parameters in symptomatic and asymptomatic plaques and studies assessed inter-observer reproducibility, and significant biases in studies assessing CEUS reproducibility were present.

CONCLUSION

CEUS is a useful vascular imaging method to differentiate between symptomatic and asymptomatic carotid plaques with moderate to excellent reproducibility. Quantitative CEUS analysis appeared to be more sensitive and reliable in assessing carotid plaques than semi-quantitative parameters. Further longitudinal prospective trials evaluating carotid plaque in asymptomatic population using CEUS to determine plaque characteristics that can become symptomatic are required.

Carotid Intraplaque Neovascularization and Future Vascular Events in Patients With Asymptomatic Carotid Stenosis

Objective: Intraplaque neovascularization is a marker of plaque vulnerability and is used to predict the risk of future vascular events in patients with symptomatic carotid stenosis; however, its association with asymptomatic carotid stenosis has not been prospectively evaluated. Therefore, this study aimed to explore the association between intraplaque neovascularization assessed using contrast-enhanced ultrasound and the occurrence of future ischemic events in asymptomatic patients diagnosed with carotid stenosis.

Methods: We recruited patients with asymptomatic carotid stenosis from our center. Contrast-enhanced ultrasound was performed at baseline. The outcomes were ischemic stroke and cardiovascular events. We plotted Kaplan-Meier survival curves and performed a log-rank test to compare endpoint event probability in patients with and without grade 2 intraplaque neovascularization. Univariate and multivariate Cox proportional hazards models were used to assess predictors of future vascular events.

Results: The data of 50 participants were included in the analysis (median follow-up, 43.7 months). Endpoint events occurred in 12 participants (24%). The Kaplan-Meier survival curves showed that patients with grade 2 intraplaque neovascularization had a higher probability of future vascular events than those with grades 0 and 1 (p < .05). Grade 2 intraplaque neovascularization (hazard ratio: 4.530, 95% confidence interval, 1.337–15.343, p < .05) was an independent predictor of future vascular events in patients with asymptomatic carotid stenosis.

Conclusion: Grade 2 intraplaque neovascularization assessed using contrast-enhanced ultrasound independently predicted future ischemic events in patients with asymptomatic carotid stenosis, and contrast-enhanced ultrasound may be an effective screening method to identify high-risk subgroups of patients with asymptomatic carotid stenosis.

Impact of H-Type Hypertension on Intraplaque Neovascularization Assessed by Contrast-Enhanced Ultrasound

Aim: H-type hypertension is connected with carotid atherosclerotic plaques and stroke, whereas neovascularization is a dominant contributor to plaque vulnerability. However, the correlation between H-type hypertension and plaque vulnerability remains unclear. This study aims to explore the influence of H-type hypertension on intraplaque neovascularization (IPN).

Methods: We enrolled 235 patients with carotid plaques into the investigation and classified them into four groups: H-type hypertension group, simple hypertension group, isolated hyperhomocysteinemia group, and control group. Contrast-enhanced ultrasound (CEUS) was performed on them and IPN was evaluated using semi-quantitative visual grading: grade 1 (no microbubbles or microbubbles limited to the adventitial side and/or shoulder of plaque) and, grade 2 (diffused microbubbles within plaque or microbubbles enter plaque core). To analyze the correlation between H-type hypertension and the degree of plaque enhancement, logistic regression was used.

Results: Compared with those with CEUS grade 1 plaques, those with CEUS grade 2 plaques had higher frequency of ischemic stroke (29.0% vs. 45.1%, P ＜0.05), hypertension (41.0% vs. 56.3%, P ＜0.05), and H-type hypertension (18.0% vs. 29.6%, P ＜0.05). No significant differences existed in plaque morphology, plaque echogenicity, and the severity of carotid artery stenosis between the degree of plaque enhancement (all P ＞0.05). H-type hypertension (multivariate-adjusted OR: 3.036, 95% CI: 1.258–7.329) was independently connected with the degree of plaque enhancement even after adjusting for other covariates.

Conclusion: H-type hypertension is expressly connected with the degree of plaque enhancement and may facilitate plaque vulnerability. Our findings may offer a new insight for treating vulnerable plaque, lowering blood pressure, and lowering homocysteine equally crucial.

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.

Long-Term Clinical Effects of Carotid Intraplaque Neovascularization in Patients with Coronary Artery Disease

Objective

To investigate the predictive value of intraplaque neovascularization (IPN) for cardiovascular outcomes.

Materials and Methods

We evaluated 217 patients with coronary artery disease (CAD) (158 men; mean age, 68 ± 10 years) with a maximal carotid plaque thickness ≥ 1.5 mm for the presence of IPN using contrast-enhanced ultrasonography. We compared patients with (n = 116) and without (n = 101) IPN during the follow-up period and investigated the predictors of major adverse cardiovascular events (MACE), including cardiac death, myocardial infarction, coronary artery revascularization, and transient ischemic accident/stroke.

Results

During the mean follow-up period of 995 ± 610 days, the MACE rate was 6% (13/217). Patients with IPN had a higher maximal thickness than those without IPN (2.86 ± 1.01 vs. 2.61 ± 0.84 mm, p = 0.046). Common carotid artery-peak systolic velocity, left ventricular mass index (LVMI), and ventricular-vascular coupling index were significantly correlated with MACE. However, on multivariate Cox regression analysis, increased LVMI was independently related to MACE (p < 0.05). The presence of IPN could not predict MACE.

Conclusion

The presence of IPN was related to a higher plaque thickness but could not predict cardiovascular outcomes better than conventional clinical factors in patients with CAD.

Carotid Intraplaque Neovascularization on Contrast-Enhanced Ultrasound Correlates with Cardiovascular Events and Poor Prognosis: A Systematic Review and Meta-analysis

The goal of this meta-analysis is to investigate whether carotid intraplaque neovascularization (IPN) on contrast-enhanced ultrasound (CEUS) correlates with past cardiovascular events (CVEs) and prognosis. The present meta-analysis included 22 studies involving 3232 patients. The pooled analysis revealed that the presence of IPN was significantly associated with a higher incidence of future CVEs (pooled relative risk = 3.28, 95% confidence interval [CI]: 2.28-4.73) and a lower event-free probability (pooled hazard ratio = 2.51, 95% CI: 1.48-4.27). The presence of IPN was significantly associated with higher rates of past cardiac events (odds ratio = 4.25, 95% CI: 2.48-7.29) and past cerebrovascular accidents (odds ratio = 4.83, 95% CI: 2.66-8.78). Our results suggest that carotid IPN on CEUS significantly correlates with past cardiac events and cerebrovascular accidents and can predict future CVEs. Carotid CEUS is useful in CVE risk stratification.