Large but Nonstenotic Carotid Artery Plaque in Patients With a History of Embolic Stroke of Undetermined Source

Dual Antiplatelet Therapy After Embolic Stroke of Undetermined Source: A Subgroup Analysis of the CHANCE-2 Trial

BACKGROUND

The atherosclerotic sources of embolism are a significant contributor to embolic stroke of undetermined source (ESUS). However, there is limited evidence for the efficacy of intensive dual antiplatelet therapy for ESUS. We conducted an investigation to determine whether gene-directed dual antiplatelet therapy could reduce the risk of recurrent stroke in patients with ESUS.

METHODS

CHANCE-2 (Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events-II) was an investigator-initiated, multicenter, randomized, double-blind, placebo-controlled trial that objectively compared ticagrelor plus aspirin and clopidogrel plus aspirin in patients with minor stroke or transient ischemic attack who carried CYP2C19 loss-of-function alleles in China. All study participants were classified into ESUS and non-ESUS groups for the prespecified exploratory analysis. Cox proportional hazards models were used to assess the interaction of the state of ESUS with the effects of dual antiplatelet therapy with ticagrelor-aspirin versus clopidogrel-aspirin, adjusting for sociodemographic and clinical factors.

RESULTS

The subgroup analysis comprised 5796 participants (90.4% of the total 6412 participants) in the CHANCE-2 trial, with a median age of 64.9 years (range, 57.0-71.4 years), of whom 1964 (33.9%) were female. These participants underwent diffusion-weighted imaging as part of the study protocol. After systematic evaluation, 15.2% of patients (881/5796) were deemed to have ESUS. The incidence of stroke recurrence in patients with ESUS was found to be 5.6% in the ticagrelor-aspirin group and 9.2% in the clopidogrel-aspirin group (hazard ratio, 0.57 [95% CI, 0.33-0.99]; P=0.04). In patients without ESUS, the respective incidence rates were 5.6% and 7.5% (hazard ratio, 0.72 [95% CI, 0.58-0.90]; P<0.01). The P value was 0.56 for the treatment × ESUS status interaction effect.

CONCLUSIONS

In this prespecified exploratory analysis, ticagrelor with aspirin was superior to clopidogrel with aspirin for preventing stroke at 90 days in patients with acute ischemic stroke or transient ischemic attack who carried CYP2C19 loss-of-function alleles and were classified as ESUS.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04078737.

Thin aortic arch plaque is associated with the development of atrial fibrillation for embolic stroke of undetermined source in patients with an insertable cardiac monitor

BACKGROUND AND OBJECTIVE

This study's objective is to investigate whether mild aortic arch plaque is associated with the development of atrial fibrillation (AF) in stroke patients with embolic stroke of undetermined source (ESUS) during the first year following the implantation of an insertable cardiac monitor (ICM).

METHODS

The participants in this cross-sectional observational study were consecutive patients with ESUS, even after transesophageal echocardiography. We assessed the relationship between the thickness of the participants' aortic arch plaque and AF detected after ICM implantation.

RESULTS

Of the 50 consecutive patients with ESUS enrolled in this study, 12 (24%) developed AF. We observed that thicker aortic arch plaque was associated with undetected AF (2.3 mm vs. 1.2 mm, p < 0.001). Aortic arch plaque thickness was independent associated with undetected AF (OR 54.00, 95% CI 2.706-1077.544, p = 0.009). When the cut-off value for aortic arch plaque thickness was 1.8 mm, the sensitivity and specificity were 71.1% and 91.7%, respectively (95% CI = 0.75-0.98, p < 0.001). Also, patients having both aortic arch plaque with a thickness < 1.8 mm and a CHADS2 score ≥ 4 were more likely to have detectable AF than no AF (88% vs. 12%, p < 0.001).

CONCLUSION

A thinner aortic arch plaque was associated with the development of AF. Patients with mild aortic plaques below 4 mm but ≥1.8 mm in thickness and without other high-risk features are less likely to have paroxysmal AF on ICM, and these plaques may be a possible source of embolism for their strokes.

Editorial: New Advances in Cerebrovascular Disorders

Cerebrovascular disorders constitute major causes of disability and mortality worldwide [...].

Dual Antiplatelet Therapies and Causes in Minor Stroke or Transient Ischemic Attack: A Prespecified Analysis in the CHANCE-2 Trial

BACKGROUND

It is unclear whether patients with different stroke/transient ischemic attack etiologies benefit differently from gene-directed dual antiplatelet therapy. This study explored the efficacy and safety of ticagrelor-aspirin versus clopidogrel-aspirin in transient ischemic attack or minor stroke with different causes in the CHANCE-2 trial (Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events-II).

METHODS

This was a prespecified analysis of the CHANCE-2 trial, which enrolled 6412 patients with minor stroke or transient ischemic attack who carried CYP2C19 loss-of-function alleles. Patients with centralized evaluation of TOAST (Trial of ORG 10172 in Acute Stroke Treatment) classification of large-artery atherosclerosis, small-vessel occlusion, and stroke of undetermined cause were included. The primary efficacy outcome was new stroke, and the primary safety outcome was severe or moderate bleeding, both within 90 days. Cox proportional hazards models were used to assess the interaction of TOAST classification with the effects of dual antiplatelet therapy with ticagrelor-aspirin versus clopidogrel-aspirin.

RESULTS

A total of 6336 patients were included in this study. In patients administered ticagrelor-aspirin and clopidogrel-aspirin, respectively, stroke recurred in 85 (9.8%) and 88 (10.7%) patients with large-artery atherosclerosis (hazard ratio, 0.86 [95% CI, 0.63-1.18]; P=0.34); 32 (3.6%) and 61 (7.0%) patients with small-vessel occlusion (hazard ratio, 0.51 [95% CI, 0.33-0.79]; P=0.002); and 68 (4.8%) and 87 (5.9%) patients with stroke of undetermined cause (hazard ratio, 0.80 [95% CI, 0.58-1.10]; P=0.17), with P=0.08 for the treatment×cause subtype interaction effect. There were no significant differences in severe or moderate bleeding events in patients with different cause and different treatment.

CONCLUSIONS

In this prespecified analysis of the CHANCE-2 trial, the efficacy and safety of ticagrelor-aspirin versus clopidogrel-aspirin in preventing new stroke were consistent in patients with different causes. The influence of stroke cause on benefit of gene-guided antiplatelet therapy should be explored by further trials.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04078737.

Associations Between GGT/ALT Ratio and Carotid Plaque in Inpatients With Coronary Artery Disease: A RCSCD-TCM Study

This study investigated the relationship between gamma-glutamyltransferase/alanine aminotransferase (GGT/ALT) ratio and carotid plaques in patients with coronary artery disease (CAD). This multicenter retrospective study included 8,255 patients with CAD who were divided according to GGT/ALT quartiles: Q1 (GGT/ALT ≤ 1.00), Q2 (1.00 < GGT/ALT ≤ 1.41), Q3 (1.41 < GGT/ALT ≤ 2.05), and Q4 (GGT/ALT > 2.05). Logistic regression was used to analyze the relationship between GGT/ALT, carotid plaques, and carotid plaque echogenicity. GGT/ALT ratio (odds ratio [OR]: 1.16; 95% confidence interval [CI]: 1.11-1.21; P < .001) was significantly associated with carotid plaque risk. The degree of relevance was higher in men (OR: 1.71; 95% CI: 1.35-2.15; P < .001) than in women (OR: 1.56; 95% CI: 1.28-1.91; P < .001). The ORs value of carotid plaque risk was higher in middle-aged patients (OR: 2.23; 95% CI: 1.78-2.80; P < .001) than in older patients (OR: 1.77; 95% CI: 1.44-2.18; P < .001). The GGT/ALT ratio was significantly associated with different carotid plaque echogenicity, and the highest OR values were for isoechoic plaques (OR: 1.18; 95% CI: 1.12-1.24; P < .001). These findings suggest that the GGT/ALT ratio might be associated with a high risk of developing carotid plaques and different types of plaque echoes and was more significantly associated with isoechoic plaques.

Vulnerable plaque of the petrous internal carotid artery in embolic stroke of undetermined source

BACKGROUND AND PURPOSE

The association between nonstenotic plaque at the petrous internal carotid artery (ICA) and embolic stroke of undetermined source (ESUS) remains unknown. We aimed to test the hypothesis that the presence of a larger build-up of petrous plaque is more prevalent in the ipsilateral versus the contralateral side among ESUS patients without plaque in the intracranial and proximal ICA.

METHODS

From a total of 243 patients with ESUS and 160 patients with small-vessel disease (SVD) without proximal ICA plaque, we enrolled 88 ESUS and 103 SVD patients without ipsilateral nonstenotic intracranial and proximal ICA plaque in the present study. Targeting the petrous segment of the ICA on two sides, plaque burden including plaque thickness, lumen area, vessel area, wall area, and percentage of luminal stenosis, and composition features (presence/absence of the ruptured fibrous cap, ulcer plaque, thrombus, discontinuity of plaque surface [DPS], intraplaque hemorrhage and complicated plaque) were assessed by high-resolution magnetic resonance imaging.

RESULTS

We found a higher prevalence of petrous plaque thickness ≥3.5 mm ipsilateral versus contralateral to the stroke (25/88 [28.4%] vs. 12/88 [13.6%], odds ratio [OR] 3.60, 95% confidence interval [CI] 1.34-9.70), but this imbalance was not seen in SVD. In patients with plaque thickness ≥3.5 mm, the presence of DPS (OR 4.05, 95% CI 1.11-14.78) and complicated plaque (OR 5.00, 95% CI 1.10-22.82) was more closely related to an index ESUS, a finding that was not evident in the subgroup with petrous plaque <3.5 mm (p for interaction = 0.027).

CONCLUSIONS

The present study provided the first evidence supporting a potential etiological role of vulnerable petrous plaque in ESUS.

Nonstenotic Carotid Plaques and Embolic Stroke of Undetermined Source: A Multimodality Review

Symptomatic nonstenotic carotid artery disease has been increasingly recognized as a thromboembolic source in patients who would otherwise be classified as having embolic stroke of undetermined source. Evidence suggests that certain plaque features seen on sonography, CT, and MR imaging in nonstenotic carotid artery disease may predispose to recurrent stroke in patients with embolic stroke of undetermined source. We performed a focused literature review to further study plaque features in the context of embolic stroke of undetermined source and to determine which plaque features may be associated with ipsilateral ischemic events in such patients. Plaque thickness as seen on both ultrasound and CT appears to have a consistent association with ipsilateral stroke in patients with embolic stroke of undetermined source across multiple studies. Intraplaque hemorrhage as seen on MR imaging is now understood to have a strong association with ipsilateral stroke in patients with embolic stroke of undetermined source. Continued study of various plaque features as seen on different modalities is warranted to uncover other potential associations.

The role of non-stenosing carotid artery plaques in embolic stroke of undetermined source, is it a silent offender? A review of literature

PURPOSE

Atherosclerotic cervical internal carotid artery disease is one of the major causes of ischemic stroke and transient ischemic attacks. The risk of stroke from mild to moderate stenoses (i.e. <50% stenosis) might be underestimated. There is increasing evidence that plaque morphological features reflect plaque instability that may harbor high risk for embolization. In this narrative review, we will review the literature on plaque features that predict vulnerability beyond the degree of stenosis, discuss the clinical association with stroke, and evaluate the evidence that these lesions serve as a source for embolic stroke of unknown source (ESUS).

METHODS

We performed a literature search using PubMed, EMBASE, and Web of Science. The terms "embolic stroke of undetermined source" and "plaque morphology" were used either alone or in combination with "non-flow limiting stenosis," "non-stenosing plaques," "high-risk plaque features" or "internal carotid artery plaque." Data on plaque morphology and ESUS were mainly taken from review articles, observational studies including retrospective cohort and cross-sectional studies, meta-analyses, and systematic reviews.

CONCLUSION

Nonstenosing carotid artery plaques with high-risk features carry a remarkable risk for stroke occurrence and randomized clinical trials are warranted for further evaluation of using carotid artery stenting or carotid endarterectomy to mitigate the risk of stroke.

Advances in Noninvasive Carotid Wall Imaging with Ultrasound: A Narrative Review

Carotid atherosclerosis is a major cause for stroke, with significant associated disease burden morbidity and mortality in Western societies. Diagnosis, grading and follow-up of carotid atherosclerotic disease relies on imaging, specifically ultrasound (US) as the initial modality of choice. Traditionally, the degree of carotid lumen stenosis was considered the sole risk factor to predict brain ischemia. However, modern research has shown that a variety of other imaging biomarkers, such as plaque echogenicity, surface morphology, intraplaque neovascularization and vasa vasorum contribute to the risk for rupture of carotid atheromas with subsequent cerebrovascular events. Furthermore, the majority of embolic strokes of undetermined origin are probably arteriogenic and are associated with nonstenosing atheromas. Therefore, a state-of-the-art US scan of the carotid arteries should take advantage of recent technical developments and should provide detailed information about potential thrombogenic (/) and emboligenic arterial wall features. This manuscript reviews recent advances in ultrasonographic assessment of vulnerable carotid atherosclerotic plaques and highlights the fields of future development in multiparametric arterial wall imaging, in an attempt to convey the most important take-home messages for clinicians performing carotid ultrasound.

The role of cross-sectional imaging of the extracranial and intracranial vasculature in embolic stroke of undetermined source

Despite an extensive workup, nearly one third of ischemic strokes are defined as Embolic Stroke of Undetermined Source (ESUS), indicating that no clear etiologic cause has been identified. Since large vessel atherosclerotic disease is a major cause of ischemic stroke, we focus on imaging of large vessel atherosclerosis to identify further sources of potential emboli which may be contributing to ESUS. For a stroke to be considered ESUS, both the extracranial and intracranial vessels must have &lt;50% stenosis. Given the recent paradigm shift in our understanding of the role of plaque vulnerability in ischemic stroke risk, we evaluate the role of imaging specific high-risk extracranial plaque features in non-stenosing plaque and their potential contributions to ESUS. Further, intracranial vessel-wall MR is another potential tool to identify non-stenosing atherosclerotic plaques which may also contribute to ESUS. In this review, we discuss the role of cross-sectional imaging of the extracranial and intracranial arteries and how imaging may potentially uncover high risk plaque features which may be contributing to ischemic strokes.

Characteristics of non-stenotic carotid plaque in embolic stroke of undetermined source compared with cardiogenic embolism: a retrospective cross-sectional observational study

Background

Non-stenotic carotid plaque is considered an important etiology of embolic stroke of undetermined source (ESUS). However, only a few previous studies included a negative control group, and the characteristics of non-stenotic carotid plaque in ESUS have yet to be investigated. The objective of this study is to explore the clinical characteristics of ESUS and the correlation between non-stenotic carotid plaque and ESUS.

Methods

This is a single-center, retrospective cross-sectional observational study conducted to compare differences in clinical information among ESUS, CE, and large-artery atherosclerosis (LAA), as well as the prevalence of non-stenotic carotid plaque and non-stenotic carotid plaque with low echo between patients with ESUS and CE in Changzhou No.2 People’s Hospital from January 2020 to January 2022. Ultrasound was used to evaluate the characteristics of non-stenotic carotid plaque and vulnerable carotid plaque was defined as plaque with low echo. The binary logistic regression model was used to analyze the relationship between the characteristics of non-stenotic carotid plaque and ESUS. The receiver-operating characteristic curve was used to evaluate the diagnostic efficiency of the characteristics of non-stenotic carotid plaque for ESUS.

Results

We had a final studying population of 280 patients including 81 with ESUS, 37 with CE, and 162 with LAA. There were no differences in clinical features between ESUS and LAA, but in the comparison of CE and ESUS, there were differences in age, smoking, hypertension, levels of triglyceride, total cholesterol, and low density lipoprotein cholesterol. In ESUS, the prevalence of non-stenotic carotid plaque was more common on the ipsilateral side of stroke than in CE [55 (67.90%) vs. 18 (48.65%), p = 0.046], so was the prevalence of non-stenotic carotid plaque with low echo [38 (46.91%) vs. 5 (13.51%), p < 0.001]. Logistic regression analysis showed that the prevalence of non-stenotic carotid plaque (OR: 4.19; 95% CI: 1.45–12.11; p = 0.008) and the prevalence of non-stenotic carotid plaque with low echo (OR: 5.12; 95% CI: 1.55–16.93; p = 0.007) were, respectively, the independent predictors of ESUS. The results receiver-operating characteristic (ROC) curve showed that the combination of age, hypertension, and ipsilateral non-stenotic carotid plaque with low echo had the best diagnostic efficiency for ESUS (0.811; 95%CI: 0.727–0.896; p < 0.001).

Conclusion

Our results suggest that ipsilateral vulnerable non-stenotic carotid plaque is associated with ESUS in anterior circulation infarction.

Features of non-stenotic carotid plaque on computed tomographic angiography in patients with embolic stroke of undetermined source

Purpose

Embolic stroke of undetermined source (ESUS) is a subset of cryptogenic stroke constituting a large proportion of acute ischemic strokes. This study aimed to assess the features of non-stenotic carotid plaque (<50%) on computed tomographic angiography (CTA) and to evaluate the association between non-stenotic carotid plaque and ESUS.

Methods

From January 1 to December 31, 2019, a total of 60 consecutive patients with primary unilateral ESUS and <50% carotid artery stenosis, as determined using screening ultrasonography, were hospitalized in the Department of Neurology of our hospital. All enrolled patients underwent CTA to determine the composition and morphological features of non-stenotic carotid plaques using consecutive sections in both carotid arteries. The features of these plaques with and without ipsilateral stroke in patients with ESUS were compared.

Results

Sixty ESUS images were included in the study, with 85 plaques. Forty-five (52.9%) of these plaques were ipsilateral and 40 (47.1%) were contralateral to the stroke. Compared to that of the contralateral plaque group, the maximum carotid plaque thickness and plaque length of the ipsilateral group were greater (2.1 mm vs. 1.5 mm, p = 0.03; 20.8 mm vs. 12.1 mm, p = 0.02); however, there were no significant differences in the degree of luminal stenosis, presence of soft plaque and calcified plaque, and the number of ulcers on the plaque surface between the two groups. Similarly, the number of plaques with thickness >3 mm in the ipsilateral group was greater than in the contralateral group (30 vs. 13, p = 0.01). A lipid core was more common in individuals with ipsilateral strokes than in those with contralateral strokes (19 vs. 7, p = 0.02). Regression analysis showed that plaque lipid core area was an independent risk factor for ESUS (odds ratio, 1.92; 95% confidence interval, 1.22–3.04; p = 0.03).

Conclusions

Non-stenotic carotid plaques could be an etiology of acute ischemic strokes classified as ESUS. The presence of a lipid core was a risk factor in individuals with non-stenotic carotid plaques.

The Relationship Between Aortic Arch Calcification and Recurrent Stroke in Patients With Embolic Stroke of Undetermined Source-A Case-Control Study

Background

Aortic arch calcification (AoAC) is associated with plaque development and cardiovascular events. We aimed to estimate the predictive value of AoAC for stroke recurrence in patients with embolic stroke of undetermined source (ESUS).

Methods

Consecutive patients with ESUS who were admitted to our center between October 2019 and October 2020 and who had a 1-year follow-up of stroke recurrence were retrospectively reviewed. According to our AoAC grading scale (AGS), AoAC was classified into four grades based on chest computed tomography (CT) findings: no visible calcification (grade 0), spotty calcification (grade 1), lamellar calcification (grade 2), and circular calcification (grade 3).

Results

Of the 158 patients with ESUS (age, 62.1 ± 14.5 years; 120 men) enrolled, 24 (15.2%) had recurrent stroke within a 1-year follow-up. The Cox regression analysis showed that stroke history [hazard ratio (HR), 4.625; 95% confidence interval (CI), 1.828–11.700, p = 0.001] and AoAC (HR, 2.672; 95% CI, 1.129–6.319; p = 0.025) predicted recurrent stroke. AGS grade 1 was associated with a significantly higher risk of stroke recurrence than AGS grade 0 (HR, 5.033; 95% CI, 1.858–13.635, p = 0.001) and AGS grade 2 plus 3 (HR, 3.388; 95% CI, 1.124–10.206, p = 0.030). In patients with AoAC, receiver operating characteristic (ROC) analysis showed that AGS had a good value in predicting stroke recurrence in patients with ESUS, with an area under curve (AUC) of 0.735 (95% CI = 0.601–0.869, p = 0.005).

Conclusions

Aortic arch calcification, especially spotty calcification, had a good predictive value for stroke recurrence in patients with ESUS.

Review and update of the concept of embolic stroke of undetermined source

Ischaemic strokes have traditionally been classified according to the TOAST criteria, in which strokes with unclear aetiology are classified as cryptogenic strokes. However, the definition of cryptogenic stroke did not meet the operational criteria necessary to define patient populations for randomized treatment trials. To address this problem, the concept of embolic stroke of undetermined source (ESUS) was developed and published in 2014. A hypothesis that underpinned this concept was that most strokes in patients with ESUS are caused by embolic events, perhaps many cardioembolic, and that anticoagulation would prevent secondary ischaemic events. On this basis, two large randomized trials were conducted to compare the non-vitamin K antagonist oral anticoagulants (NOACs) dabigatran and rivaroxaban with aspirin. Neither NOAC was superior to aspirin in these trials, although subgroups of patients with ESUS seemed to benefit specifically from anticoagulation or antiplatelet therapy. The neutral results of the trials of anticoagulation and insights into ESUS from research conducted since the concept was introduced warrant reassessment of the ESUS construct as a research concept and a treatment target. In this Review, we discuss the evidence produced since the concept of ESUS was introduced, and propose updates to the criteria and diagnostic algorithm in light of the latest knowledge.

Classification of patients with embolic stroke of undetermined source in cardioembolic and non-cardioembolic profiles

BACKGROUND

It is currently thought that embolic stroke of undetermined source (ESUS) patients have diverse underlying hidden etiologies, of which cardioembolism is one of the most important. This subgroup of patients could theoretically benefit from oral anticoagulation, but it remains unclear if these of patients can be correctly identified from other ESUS-subgroups and which markers should be used. We aimed to determine whether a machine learning (ML) model could discriminate ESUS patients into cardioembolic and non-cardioembolic profiles using baseline demographic and laboratory variables.

METHODS

Based on a prospective registry of consecutive ischemic stroke patients submitted to acute revascularization therapies, a ML model was trained using data on age, sex and 11 selected baseline laboratory parameters of patients with known stroke etiology with the aim of correctly identifying patients with cardioembolic and non-cardioembolic etiologies. The resulting model was used to classify ESUS patients into either cardioembolic or non-cardioembolic profiles.

RESULTS

The ML model was able to distinguish patients with known stroke etiology into cardioembolic or non-cardioembolic with excellent accuracy (area under the curve = 0.82). When applied to ESUS patients, the model classified 40.3% of them as having cardioembolic profiles. ESUS patients with cardioembolic profiles were older, more frequently female, more frequently had hypertension, less frequently were active smokers, had higher CHA2DS2-VASc scores, and had more premature atrial complexes per hour.

CONCLUSIONS

A ML model based on baseline demographic and laboratory parameters was able to classify ESUS patients in cardioembolic and non-cardioembolic profiles and predicted that 40% of the ESUS patients have a cardioembolic profile.

Age Alters Prevalence of Left Atrial Enlargement and Nonstenotic Carotid Plaque in Embolic Stroke of Undetermined Source

BACKGROUND

Nonstenotic carotid plaque and undetected atrial fibrillation are potential mechanisms of embolic stroke of undetermined source (ESUS), but it is unclear which is more likely to be the contributing stroke mechanism. We explored the relationship between left atrial enlargement (LAE) and nonstenotic carotid plaque across age ranges in an ESUS population.

METHODS

A retrospective multicenter cohort of consecutive patients with unilateral, anterior circulation ESUS was queried (2015 to 2021). LAE and plaque thickness were determined by transthoracic echocardiography and computed tomography angiography, respectively. Descriptive statistics were used to compare plaque features in relation to age and left atrial dimensions.

RESULTS

Among the 4155 patients screened, 273 (7%) met the inclusion criteria. The median age was 65 years (interquartile range [IQR] 54-74), 133 (48.7%) were female, and the median left atrial diameter was 3.5 cm (IQR 3.1-4.1). Patients with any LAE more frequently had hypertension (85.9% versus 67.2%, P<0.01), diabetes (41.0% versus 25.6%, P=0.01), dyslipidemia (56.4% versus 40.0%, P=0.01), and coronary artery disease (22.8% versus 11.3%, P=0.02). Carotid plaque thickness was greater ipsilateral versus contralateral to the stroke hemisphere in the overall cohort (median 1.9 mm [IQR 0-3] versus 1.5 mm [IQR 0-2.6], P<0.01); however, this was largely driven by the subgroup of patients without any LAE (median 1.8 mm [IQR 0-2.9] versus 1.5 mm [IQR 0-2.5], P<0.01). Compared with patients ≥70 years, younger patients had more carotid plaque ipsilateral versus contralateral (mean difference 0.42 mm±1.24 versus 0.08 mm±1.54, P=0.047) and less moderate-to-severe LAE (6.3% versus 15.3%, P=0.02).

CONCLUSIONS

Younger patients with ESUS had greater prevalence of ipsilateral nonstenotic plaque, while the elderly had more LAE. The differential effect of age on the probability of specific mechanisms underlying ESUS should be considered in future studies.

Low-/high-density lipoprotein cholesterol ratio and carotid plaques in patients with coronary heart disease: a Chinese cohort study

BACKGROUND

Evidence on the relationship between the low-/high-density lipoprotein cholesterol ratio (LDL-C/HDL-C) and carotid plaques remains limited. This study aimed to examine the association between LDL-C/HDL-C and carotid plaques in participants with coronary heart disease (CHD) and to further explore the extent to which a healthy lifestyle reduces the risk of LDL-C/HDL-C-related carotid plaques.

METHODS

This large-scale and multi-centre retrospective study included 9426 CHD patients (aged 35-75 years) between January 1, 2014 and September 30, 2020. The LDL-C/HDL-C values were converted to the following tertiles: lowest (< 2.15), middle (2.15-3), and highest (> 3). Healthy lifestyle-related factors referred to whether or not the participant was a non-smoker and non-drinker. Participants were divided into an unfavourable group (those who did not adhere to healthy lifestyle factors), intermediate (only one unhealthy factor), and favourable (neither of the two unhealthy factors). Logistic regression was used for statistical analyses.

RESULTS

Of the 9426 participants, 6989 (74.15%) CHD patients had carotid plaques. After adjustment for confounders, each unit increase in the LDL-C/HDL-C was significantly associated with carotid plaques (OR: 1.61; 95%CI: 1.43-1.84; P <  0.001). Multivariate logistic regression revealed that carotid plaques risk for the highest tertile (> 3) was 1.18 times that of the lowest quartile (< 2.15). Compared with an unfavourable lifestyle, an intermediate or a favourable lifestyle was associated with a significant 30% (OR: 0.70; 95%CI: 0.64-0.78; P <  0.001) or 67% (OR: 0.33; 95%CI: 0.29-0.37; P <  0.001) reduction in carotid plaques risk, respectively, among CHD patients with high LDL-C/HDL-C. There were significantly additive and multiplicative interactions between lifestyle and LDL-C/HDL-C with regards to carotid plaques.

CONCLUSION

A high LDL-C/HDL-C is associated with a risk of carotid plaques developing in CHD patients. Adhering to a healthy lifestyle has additive beneficial effects on reducing the risk of carotid plaques, especially in relation to the highest LDL-C/HDL-C.

Supracardiac atherosclerosis in embolic stroke of undetermined source: the underestimated source

The term 'embolic stroke of undetermined source' (ESUS) is used to describe patients with a non-lacunar ischaemic stroke without any identified embolic source from the heart or the arteries supplying the ischaemic territory, or any other apparent cause. When the ESUS concept was introduced, covert atrial fibrillation was conceived to be the main underlying cause in the majority of ESUS patients. Another important embolic source in ESUS is the atherosclerotic plaque in the carotid, vertebrobasilar, and intracranial arteries, or the aortic arch-collectively described as supracardiac atherosclerosis. There is emerging evidence showing that the role of supracardiac atherosclerosis is larger than it was initially perceived. Advanced imaging methods are available to identify plaques which high embolic risk. The role of novel antithrombotic strategies in these patients needs to be assessed in randomized controlled trials. This review presents the evidence which points towards a major aetiological association between atherosclerotic plaques and ESUS, summarizes the imaging features which may aid to identify plaques more likely to be associated with ESUS, discusses strategies to reduce the associated stroke risk, and highlights the rationale for future research in this field.

Symptomatic nonstenotic carotid disease: Evaluation of a proposed classification scheme in a prospective cohort

INTRODUCTION

Unraveling symptomatic nonstenotic carotid disease (SyNC) as a stroke etiology from other cryptogenic stroke may have important implications for defining natural history and for tailoring secondary prevention strategies. We aim to describe the characteristics of the plaques in a prospectively-collected cohort of patients with non-invasive imaging suggesting symptomatic carotid stenosis but whose DSA demonstrated nonstenotic atheromatous disease, and to evaluate the recurrence rate depending on the type of SyNC.

METHODS

We reviewed prospectively-collected data for patients presenting with new neurologic events and non-invasive imaging suggestive of moderate or severe (≥50%) carotid stenosis between July 2016 and October 2018. Patients were included in the present study if the degree of stenosis on DSA was < 50%. We assigned these patients into groups based on a previously-proposed working definition of SyNC, and analyzed the rate of recurrent stroke in the following 6 months.

RESULTS

28 patients had DSA-confirmed < 50% stenosis and constituted the study cohort. The median age was 73 years and 64% were male; median presenting NIHSS was 1 (IQR 0-3). The great majority (86%) of carotid plaques had high-risk features including ulcerated plaque (n = 21, 75%) and plaque > 3 mm thick (n = 18, 64%). 17 of 28 patients (61%) met classification criteria for "definite" or "probable" SyNC. Three of five patients in the "definite SyNC" group experienced recurrent neurologic events.

CONCLUSION

The majority of patients with non-invasive imaging suggesting carotid stenosis harbor symptomatic carotid disease per current classifications despite DSA stenosis < 50%. Current classification schema may allow for risk stratification of SyNC patients and these findings warrant further study.

[Embolic stroke of undetermined source (ESUS) - Classification of a new stroke entity]

Embolic stroke of undetermined source (ESUS) represents a subpopulation of cryptogenic strokes defined by its embolic stroke pattern on imaging and if after a carefully performed diagnostic evaluation, a specific, well recognized cause of stroke has not been identified. This review article analyses the basics of the ESUS concept and provides an overview of the evidence from recent cohort studies. The definition, aetiology and diagnosis of ESUS are reassessed. Targeted diagnostics in ESUS patients can reduce the number of cryptogenic strokes by making a specific diagnosis.

Ultrasound Assessment of Extracranial Carotids and Vertebral Arteries in Acute Cerebral Ischemia

Assessing ischemic etiology and mechanism during the acute phase of an ischemic stroke is crucial in order to tailor and monitor appropriate treatment and determine prognosis. Cervical Duplex Ultrasound (CDU) has evolved since many years as an excellent screening tool for the evaluation of extracranial vasculature. CDU has the advantages of a low cost, easily applicable, bed side examination with high temporal and spatial resolution and without exposing the patients to any significant complications. It represents an easily repeatable test that can be performed in the emergency room as a first-line examination of cervical artery pathology. CDU provides well validated estimates of the type of the atherosclerotic plaque, the degree of stenosis, as well as structural and hemodynamic information directly about extracranial vessels (e.g., subclavian steal syndrome) and indirectly about intracranial circulation. CDU may also aid the diagnosis of non-atherosclerotic lesions of vessel walls including dissections, arteritis, carotid-jugular fistulas and fibromuscular dysplasias. The present narrative review outlines all potential applications of CDU in acute stroke management and also highlights its potential therapeutic implications.

Dynamic Cerebral Autoregulation in Embolic Stroke of Undetermined Source

BACKGROUND AND PURPOSE

Dynamic cerebral autoregulation (dCA) in acute ischemic stroke is probably compromised. Although the characteristics of dCA in different types of stroke have been largely investigated, dCA in embolic stroke of undetermined source (ESUS) remains poorly understood. In this group, we aimed to elucidate the characteristics of dCA and their relevance to clinical outcomes.

METHODS

The study enrolled 77 ESUS patients and 50 controls. Bilateral cerebral blood flow velocities (CBFV) of middle cerebral arteries and arterial blood pressure were simultaneously recorded using a transcranial Doppler combined with a servo-controlled finger plethysmograph. Transfer function analysis was used to obtain dCA parameters including phase, gain, coherence at very low frequency (VLF) and low frequency (LF), and the rate of recovery (RoRc) of CBFV. A multivariable logistic regression model was established to explore the relationship between dCA and clinical outcomes.

RESULTS

Gain at VLF and LF, phase at LF, and RoRc of CBFV in bilateral hemispheres of the ESUS group were consistently worse than those of the control group (all P < 0.001). Bilateral RoRc of CBFV was significantly higher in patients with favorable outcomes than in those with unfavorable outcomes (stroke hemisphere: P < 0.001; non-stroke hemisphere, P = 0.029). Rate of recovery of CBFV in stroke hemisphere >13.3%/s was an independent predictor of favorable clinical outcomes (adjusted odds ratio = 30.95, 95% CI: 5.33-179.81, P < 0.001).

CONCLUSIONS

Dynamic cerebral autoregulation was relatively impaired in both stroke and non-stroke hemispheres in ESUS patients, and functioning dCA after ESUS may indicate favorable clinical outcomes.

Carotid Atherosclerosis and Patent Foramen Ovale in Embolic Stroke of Undetermined Source

BACKGROUND

Carotid atherosclerosis and likely pathogenic patent foramen ovale (PFO) are two potential embolic sources in patients with embolic stroke of undetermined source (ESUS). The relationship between these two mechanisms among ESUS patients remains unclear.

AIM

To investigate the relation between carotid atherosclerosis and likely pathogenic PFO in patients with ESUS. We hypothesized that ipsilateral carotid atherosclerotic plaques are less prevalent in ESUS with likely pathogenic PFO compared to patients with likely incidental PFO or without PFO.

METHODS

The presence of PFO was assessed with transthoracic echocardiography with microbubble test and, when deemed necessary, through trans-oesophageal echocardiography. The presence of PFO was considered as likely incidental if the RoPE (Risk of Paradoxical Embolism) score was 0-6 and likely pathogenic if 7-10.

RESULTS

Among 374 ESUS patients (median age: 61years, 40.4% women), there were 63 (49.6%) with likely incidental PFO, 64 (50.4%) with likely pathogenic PFO and 165 (44.1%) with ipsilateral carotid atherosclerosis. The prevalence of ipsilateral carotid atherosclerosis was lower in patients with likely pathogenic PFO (7.8%) compared to patients with likely incidental PFO (46.0%) or patients without PFO (53.0%) (p<0.001). After adjustment for multiple confounders, the prevalence of ipsilateral carotid atherosclerosis remained lower in patients with likely pathogenic PFO compared to patients with likely incidental PFO or without PFO (adjusted OR=0.32, 95%CI:0.104-0.994, p=0.049).

CONCLUSIONS

The presence of carotid atherosclerosis is inversely related to the presence of likely pathogenic PFO in patients with ESUS.

Data-driven machine-learning analysis of potential embolic sources in embolic stroke of undetermined source

BACKGROUND AND PURPOSE

Hierarchical clustering, a common 'unsupervised' machine-learning algorithm, is advantageous for exploring potential underlying aetiology in particularly heterogeneous diseases. We investigated potential embolic sources in embolic stroke of undetermined source (ESUS) using a data-driven machine-learning method, and explored variation in stroke recurrence between clusters.

METHODS

We used a hierarchical k-means clustering algorithm on patients' baseline data, which assigned each individual into a unique clustering group, using a minimum-variance method to calculate the similarity between ESUS patients based on all baseline features. Potential embolic sources were categorised into atrial cardiopathy, atrial fibrillation, arterial disease, left ventricular disease, cardiac valvulopathy, patent foramen ovale (PFO) and cancer.

RESULTS

Among 800 consecutive ESUS patients (43.3% women, median age 67 years), the optimal number of clusters was four. Left ventricular disease was most prevalent in cluster 1 (present in all patients) and perfectly associated with cluster 1. PFO was most prevalent in cluster 2 (38.9% of patients) and associated significantly with increased likelihood of cluster 2 [adjusted odds ratio: 2.69, 95% confidence interval (CI): 1.64-4.41]. Arterial disease was most prevalent in cluster 3 (57.7%) and associated with increased likelihood of cluster 3 (adjusted odds ratio: 2.21, 95% CI: 1.43-3.13). Atrial cardiopathy was most prevalent in cluster 4 (100%) and perfectly associated with cluster 4. Cluster 3 was the largest cluster involving 53.7% of patients. Atrial fibrillation was not significantly associated with any cluster.

CONCLUSIONS

This data-driven machine-learning analysis identified four clusters of ESUS that were strongly associated with arterial disease, atrial cardiopathy, PFO and left ventricular disease, respectively. More than half of the patients were assigned to the cluster associated with arterial disease.

The Risk of Stroke and TIA in Nonstenotic Carotid Plaques: A Systematic Review and Meta-Analysis

BACKGROUND

Severe carotid stenosis carries a high risk of stroke. However, the risk of stroke with nonstenotic carotid plaques (<50%) is increasingly recognized.

PURPOSE

We aimed to summarize the risk of TIA or stroke in patients with nonstenotic carotid plaques.

DATA SOURCES

We performed a comprehensive systematic review and meta-analysis in patients with acute ischemic stroke in whom carotid imaging was performed using MEDLINE and the Cochrane Database, including studies published up to December 2019.

STUDY SELECTION

Included studies had >10 patients with <50% carotid plaques on any imaging technique and reported the incidence or recurrence of ischemic stroke/TIA. High-risk plaque features and the risk of progression to stenosis >50% were extracted if reported.

DATA SYNTHESIS

We identified 31 studies reporting on the risk of ipsilateral stroke/TIA in patients with nonstenotic carotid plaques. Twenty-five studies (n = 13,428 participants) reported on first-ever stroke/TIA and 6 studies (n = 122 participants) reported on the recurrence of stroke/TIA.

DATA ANALYSIS

The incidence of first-ever ipsilateral stroke/TIA was 0.5/100 person-years. The risk of recurrent stroke/TIA was 2.6/100 person-years and increased to 4.9/100 person-years if intraplaque hemorrhage was present. The risk of progression to severe stenosis (>50%) was 2.9/100 person-years (8 studies, n = 448 participants).

LIMITATIONS

Included studies showed heterogeneity in reporting stroke etiology, the extent of stroke work-up, imaging modalities, and classification systems used for characterizing carotid stenosis.

CONCLUSIONS

The risk of recurrent stroke/TIA in nonstenotic carotid plaques is not negligible, especially in the presence of high-risk plaque features. Further research is needed to better define the significance of nonstenotic carotid plaques for stroke etiology.

Embolic Stroke of Undetermined Source: Gateway to a New Stroke Entity?

Embolic stroke of unknown source (ESUS) is currently thought to represent a subpopulation of cryptogenic strokes defined by its embolic stroke pattern on imaging, and if after a carefully performed diagnostic evaluation, a specific, well-recognized cause of stroke has not been identified. The concept was primarily established to justify and enable the conduct of the ESUS trials, such as Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate versus Acetylsalicylic Acid in Patients with Embolic Stroke of Undetermined Source (RESPECT-ESUS) and New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial versus aspirin to Prevent Embolism in Embolic Stroke of Undetermined Source (NAVIGATE-ESUS). With both studies having neutral results, the question arises if the ESUS concept is misleading or rather a gateway for a modern understanding of stroke etiology. This review will analyze the background of the ESUS concept, overview the results and the impact of the recent multicenter trials and cohort studies, and discuss the definition, etiology, and diagnosis of ESUS.

Embolic Stroke of Undetermined Source and Sleep Disorders

Background and Purpose—

Compared with other causes of ischemic stroke, the mechanism of action of embolic stroke of undetermined source (ESUS) remains unclear, with previous literature suggesting that ESUS may be due to an undetected cardioembolic source. This study aimed to improve our understanding of the pathophysiology of ESUS through current knowledge of sleep disorders.

Methods—

Patients were included in this study if they sustained an ischemic stroke and completed either polysomnography or a home sleep apnea test. Strokes were classified into 1 of 6 mechanisms and were compared with the presence of sleep disorders (ie, obstructive sleep apnea, periodic limb movements, and abnormalities in sleep architecture).

Results—

There was a significant relationship between obstructive sleep apnea and cardioembolic stroke mechanism compared with the other stroke mechanisms ( P =0.018). There was no significant relationship between obstructive sleep apnea and ESUS ( P =0.585). Patients with ESUS were significantly more likely to have an elevated periodic limb movement index ( P =0.037) and prolonged sleep onset latency ( P =0.0166) compared with patients with other causes of stroke.

Conclusions—

ESUS was not associated with markers of cardioembolic stroke such as obstructive sleep apnea. There was a significant relationship between ESUS and elevated periodic limb movements and impaired sleep architecture, which suggests that ESUS may have a multifactorial underlying pathophysiology.

Clinical Features of Embolic Stroke of Undetermined Source

Background and Objective: One-third of ischemic strokes have no identifiable cause following standard evaluation. In 2014, researchers have proposed the concept of Embolic Stroke of Undetermined Source (ESUS). The purpose of this study was to report the clinical characteristics of ESUS and its difference from cardiogenic embolism (CE), large-artery atherosclerosis (LA), and small-artery occlusion lacunar (SA).

Methods: Acute ischemic stroke (AIS) patients admitted to the department of Beijing Haidian Hospital from January 2017 to December 2017 were prospectively and consecutively enrolled. Base-line characteristics were collected. Stroke etiologies were presented and compared. We compared the clinical features and infarct sites of patients with acute cerebral infarction of different etiologies.

Results: A total of 119 AIS patients were analyzed in the study. There were 33 (27.73%) cases in ESUS group, 11 (9.24%) cases in CE group, 45 (37.82%) cases in LAA group and 30 (25.21%) cases in SA group. There were significant differences between the ESUS group and the CE group in the NIHSS score [3 (1.5–5) vs. 6 (2–20), p = 0.007], Modified Rankin Score [19, (57.58) vs. 9, (81.82), p = 0.008], hemorrhagic transformation [0, (0) vs. 5, (45.45), p < 0.001], and left atrial diameter [37.09 ± 3.16 vs. 41.73 ± 5.00, p = 0.001]. ESUS group and LA group have different mRS scores [19, (57.58) vs. 42, (93.33), p < 0.001]. ESUS group and SA group have different mRS scores [19, (57.58) vs. 28, (93.33), p = 0.001]. During 1 year follow-up, there were 5 cases (15.15%) in ESUS group, 3 cases (27.27%) in CE group, 3 cases (6.67%) in LA group, and 1 case (3.33%) in SA group with ischemic stroke (cerebral infarction or transient ischemic attack).

Conclusion: ESUS is more similar to atherosclerotic cerebral infarction in clinical features, but the distribution of lesions is more similar to cardiogenic embolism, suggesting that the pathogenesis of ESUS needs to be further explored.

Prevalence of Nonstenotic Carotid Plaque in Stroke Due to Atrial Fibrillation Compared to Embolic Stroke of Undetermined Source

BACKGROUND

Embolic stroke of undetermined source (ESUS) accounts for about 20% of strokes. Nonstenotic cervical arterial plaque may be a mechanism of stroke in a subset of these patients.

METHODS

A cohort of consecutive patients with ischemic stroke was retrospectively identified from a stroke registry. Patients with unilateral anterior circulation embolic stroke due to atrial fibrillation (AF) or consistent with ESUS who underwent computed tomographic neck angiography were included. The prespecified primary outcome was a comparison of the prevalence of carotid plaque greater than or equal to 3 mm thickness ipsilateral versus contralateral to the infarct side.

RESULTS

Of 772 screened patients, 96 patients with ESUS and 99 patients with AF were included. Plaque greater than or equal to 3 mm was more frequently ipsilateral than contralateral to the infarct in patients with ESUS (41% versus 29%, P = .03), and plaque thickness was greater ipsilateral compared to contralateral (median 2.5 versus 2.2 mm, P = .02). No significant differences in plaque characteristics ipsilateral compared to contralateral were found in patients with AF. The prevalence of ipsilateral versus contralateral plaque was greater in ESUS patients less than or equal to 65 years old (48% versus 19%, P < .01), but no different in patients greater than 65 years old (35% versus 39%, P = .57).

CONCLUSIONS

Nonstenotic cervical carotid plaque is more common ipislateral to the infarction in patients with ESUS, but not in patients with AF, supporting an underlying atheroembolic mechanism in a subset of ESUS patients. This association might be greater in younger ESUS patients.

[Embolic stroke of undetermined source (ESUS) : How much monitoring is necessary?]

The clinical construct of embolic stroke of unknown source (ESUS) was first described in 2014. It is defined as cryptogenic ischemic stroke after the exclusion of a lacunar infarct, a significant (≥50%) stenosis of extracranial or intracranial arteries and a cardiac source of embolism. Initially, there was hope that these patients would benefit from anticoagulation. This was based on the suspicion that imaging criteria of stroke mimic features of embolism from cardiac sources or the great arteries. In two large randomized trials with 12,600 patients neither rivaroxaban nor dabigatran could reduce the risk of recurrent stroke. Based on these results, current research is focused on paroxysmal atrial fibrillation as a potential cause of stroke in these patients. Several randomized trials could show that by prolongation of monitoring to 30 days atrial fibrillation can be detected in approximately 10% of the patients. Using continuous monitoring (e. g. by implantable loop recorders) atrial fibrillation can even be detected in one quarter of the patients. Not all stroke patients can receive such an intensive monitoring. Therefore, this article summarizes the evidence and presents the resulting recommendations for patient selection and staged rhythm diagnostics and discusses a recently presented algorithm of an expert group for use in daily clinical practice.