Symptomatic Carotid Artery Disease Research Articles

Using machine learning to predict carotid artery symptoms from CT angiography: A radiomics and deep learning approach

PurposeTo assess radiomics and deep learning (DL) methods in identifying symptomatic Carotid Artery Disease (CAD) from carotid CT angiography (CTA) images. We further compare the performance of these novel methods to the conventional calcium score. MethodsCarotid CT angiography (CTA) images from symptomatic patients (ischaemic stroke/transient ischaemic attack within the last 3 months) and asymptomatic patients were analysed. Carotid arteries were classified into culprit, non-culprit and asymptomatic. The calcium score was assessed using the Agatston method. 93 radiomic features were extracted from regions-of-interest drawn on 14 consecutive CTA slices. For DL, convolutional neural networks (CNNs) with and without transfer learning were trained directly on CTA slices. Predictive performance was assessed over 5-fold cross validated AUC scores. SHAP and GRAD-CAM algorithms were used for explainability. Results132 carotid arteries were analysed (41 culprit, 41 non-culprit, and 50 asymptomatic). For asymptomatic vs symptomatic arteries, radiomics attained a mean AUC of 0.96(± 0.02), followed by DL 0.86(± 0.06) and then calcium 0.79(± 0.08). For culprit vs non-culprit arteries, radiomics achieved a mean AUC of 0.75(± 0.09), followed by DL 0.67(± 0.10) and then calcium 0.60(± 0.02). For multi-class classification, the mean AUCs were 0.95(± 0.07), 0.79(± 0.05), and 0.71(± 0.07) for radiomics, DL and calcium, respectively. Explainability revealed consistent patterns in the most important radiomic features. ConclusionsOur study highlights the potential of novel image analysis techniques in extracting quantitative information beyond calcification in the identification of CAD. Though further work is required, the transition of these novel techniques into clinical practice may eventually facilitate better stroke risk stratification.

Derivation of a clinical prediction score for the diagnosis of clinically significant symptomatic carotid artery disease.

Emergent vascular imaging identifies a subset of patients requiring immediate specialized care (i.e. carotid stenosis > 50%, dissection or free-floating thrombus). However, most TIA patients do not have these findings, so it is inefficient to image all TIA patients in crowded emergency departments (ED). Our objectives were to derive and internally validate a clinical prediction score for clinically significant carotid arterydisease in TIA patients. This was a planned secondary analysis of a prospective cohort study from 14 Canadian EDs. Among 11555 consecutive adult ED patients with TIA/minor stroke symptoms over 12 years, 9882 had vascular imaging and were included in the analysis. Our main outcome was clinically significant carotid artery disease, defined as extracranial internal carotid stenosis ≥ 50%, dissection, or thrombus in the internal carotid artery, with contralateral symptoms. Of 9882 patients, 888 (9.0%) had clinically significant carotid artery disease. Logistic regression was used to derive a 13-variable reduced model. We simplified the model into a score (Symcard [Symptomatic carotid artery disease] Score), with suggested cut-points for high, medium, and low-risk stratification. A substantial portion (38%) of patients were classified as low-risk, 33.8% as medium risk, and 28.2% as high risk. At the low-risk cut-point, sensitivity was 92.9%, specificity 41.1%, and diagnostic yield 1.7%. This simple score can predict carotid artery disease in TIA patients using readily available information. It identifies low-risk patients who can defer vascular imaging to an outpatient or specialty clinic setting. Medium-risk patients may undergo imaging immediately or with slight delay, depending on local resources. High-risk patients should undergo urgent vascular imaging.

Individualized MRI-based stroke PRediction scOre using plaque Vulnerability for symptomatic carotid artEry disease patients (IMPROVE).

In TIA and stroke patients with carotid stenosis, estimations of future ipsilateral ischemic stroke risk and treatment decisions are currently primarily based on the degree of stenosis. Intraplaque hemorrhage (IPH), which can be readily visualized on carotid MRI, is increasingly established as an easy to assess and a very strong and independent predictor for ipsilateral stroke risk, stronger than any clinical risk factor. We developed a clinical prediction model (IMPROVE) incorporating IPH, degree of stenosis, and clinical risk factors to select patients with symptomatic carotid stenosis at high risk for stroke. IMPROVE was developed on pooled clinical and MRI data from five cohort studies of 760 recent TIA or minor stroke patients with carotid plaque who received optimal medical treatment. We used Cox proportional hazards models to determine the coefficients of IMPROVE. IMPROVE was internally validated using bootstrapping and converted to one- and three-year ipsilateral ischemic stroke risk. The development dataset contained 65 ipsilateral incident ischemic strokes that occurred during a median follow-up of 1.2 years (IQR: 0.5-4.1). The IMPROVE model includes five predictors, which are in order of importance: degree of stenosis, presence of IPH on MRI, classification of last event (cerebral vs ocular), sex, and age. Internal validation revealed a good accuracy (C-statistic: 0.82; 95% CI: 0.77-0.87) and no evidence for miscalibration (calibration slope: 0.93). Using presence of IPH on MRI and only four conventional parameters, the IMPROVE model provides accurate individual stroke risk estimates, which may facilitate stratification for revascularization.

Atherosclerotic carotid artery disease Radiomics: A systematic review with meta-analysis and radiomic quality score assessment

BackgroundStroke, a leading global cause of mortality and neurological disability, is often associated with atherosclerotic carotid artery disease. Distinguishing between symptomatic and asymptomatic carotid artery disease is crucial for appropriate treatment decisions. Radiomics, a quantitative image analysis technique, and ML have emerged as promising tools in medical imaging, including neuroradiology. This systematic review and meta-analysis aimed to evaluate the methodological quality of studies employing radiomics for atherosclerotic carotid artery disease analysis and ML algorithms for culprit plaque identification using CT or MRI. Materials and methodsPubmed, WoS and Scopus databases were searched for relevant studies published from January 2005 to May 2023. RQS assessed methodological quality of studies included in the review. QUADAS-2 assessed the risk of bias. A meta-analysis and three meta regressions were conducted on study performance based on model type, imaging modality and segmentation method. ResultsRQS assessed methodological quality, revealing an overall low score and consistent findings with other radiology domains. QUADAS-2 indicated an overall low risk, except for a single study with high bias. The meta-analysis demonstrated that radiomics-based ML models for predicting culprit plaques had a satisfactory performance, with an AUC of 0.85, surpassing clinical models. However, combining radiomics with clinical features yielded the highest AUC of 0.89. Meta-regression analyses confirmed these findings. MRI-based models slightly outperformed CT-based ones, but the difference was not significant. ConclusionIn conclusion, radiomics and ML hold promise for assessing carotid plaque vulnerability, aiding in early cerebrovascular event prediction. Combining radiomics with clinical data enhances predictive performance.

Cerebral Blood Flow Patterns in Patients With Low-Flow Carotid Artery Stenosis, a 4D-PCMRI Assessment.

Compromised cerebral blood flow can contribute to future ischemic events in patients with symptomatic carotid artery disease. However, there is limited knowledge of the effects on cerebral hemodynamics resulting from a reduced internal carotid artery (ICA) blood flow rate (BFR). Investigate how reduced ICA-BFR, relates to BFR in the cerebral arteries. Prospective. Thirty-eight patients, age 72 ± 6 years (11 female). 3-Tesla, four-dimensional phase-contrast magnetic resonance imaging (4D-PCMRI). Patients with ischemic stroke or transient ischemic attack were evaluated regarding the degree of stenosis. 4D-PCMRI was used to measure cerebral BFR in 38 patients with symptomatic carotid stenosis (≥50%). BFR in the cerebral arteries was assessed in two subgroups based on symptomatic ICA-BFR: reduced ICA-flow (<160 mL/minutes) and preserved ICA-flow (≥160 mL/minutes). BFR laterality was defined as a difference in the paired ipsilateral-contralateral arteries. Patients were grouped based on ICA-BFR (reduced vs. preserved). Statistical tests (independent sample t-test/paired t-test) were used to compare groups and hemispheres. Significance was determined at P < 0.05. The degree of stenosis was not significantly different, 80% (95% confidence interval [CI] = 73%-87%) in the reduced ICA-flow vs. 72% (CI = 66%-76%) in the preserved ICA-flow; P = 0.09. In the reduced ICA-flow group, a significantly reduced BFR was found in the ipsilateral middle cerebral artery and anterior cerebral artery (A1), while significantly increased in the contralateral A1. Retrograde BFR was found in the posterior communicating artery and ophthalmic artery. Significant BFR laterality was present in all paired arteries in the reduced ICA-flow group, contrasting the preserved ICA-flow group (P = 0.14-0.93). 4D-PCMRI revealed compromised cerebral BFR due to carotid stenosis, not possible to detect by solely analyzing the degree of stenosis. In patients with reduced ICA-flow, collaterals were not sufficient to maintain symmetrical BFR distribution to the two hemispheres. 2 TECHNICAL EFFICACY: Stage 3.

A SINGLE-CENTER COMPARATIVE STUDY OF ENDARTERECTOMY AND STENTING FOR SYMPTOMATIC CAROTID ARTERY DISEASE: DECISION-MAKING PROCESSES AND EARLY TO MID-TERM OUTCOMES

Introduction: Ischemic stroke constitutes a significant burden on global health. Carotid artery atherosclerosis is a significant contributor to the occurrence of ischemic strokes. Both carotid endarterectomy and stenting are viable treatment options for symptomatic carotid artery disease, yet the optimal choice between them remains debated, particularly in elderly patients with multiple comorbidities. This study aims to compare decision-making processes and early to mid-term outcomes between carotid endarterectomy and carotid artery stenting in elderly symptomatic carotid artery disease patients. Materials and Method: A total of 88 symptomatic carotid artery disease patients (carotid endarterectomy: n=35, mean age: 71.72±7.87 years; carotid artery stenting: n=53, mean age: 70.64±7.46 years) were retrospectively analyzed. Results: No significant differences were observed in demographic characteristics between carotid endarterectomy and stenting groups. Chronic renal disease was more prevalent in the carotid endarterectomy group. Carotid artery stenting patients had a higher prevalence of 50–69% stenosis and less plaque ulceration. Complication rates were comparable between groups, with longer intensive care and hospitalization durations in the carotid endarterectomy group. Mid-term mortality rates and major complications did not significantly differ between groups. Conclusion: Both carotid endarterectomy and carotid artery stenting are effective treatments for symptomatic carotid artery disease. Despite differences in lesion characteristics, complication rates were similar between carotid endarterectomy and carotid artery stenting. This study emphasized the efficacy of a full cooperation between the cardiovascular surgery and neurology teams through an in-depth evaluation of each of the patients and the creation of individualized treatment strategies that optimized overall outcomes. Keywords: Aged; Endarterectomy; Carotid; Carotid Stenosis; Stents.

Identification of symptomatic carotid artery plaque: a predictive model combining angiography with optical coherence tomography.

Symptomatic carotid artery disease is indicative of an elevated likelihood of experiencing a subsequent stroke, with the morphology of plaque and its specific features being closely linked to the risk of stroke occurrence. Our study based on the characteristics of carotid plaque assessed by optical coherence tomography (OCT), the plaque morphology evaluated by digital subtraction angiography (DSA) and clinical laboratory indicators were combined, develop a combined predictive model to identify symptomatic carotid plaque. Patients diagnosed with carotid atherosclerotic stenosis who underwent whole-brain DSA and OCT examination at the Affiliated Hospital of Jining Medical University from January 2021 to November 2023 were evaluated. Clinical features, as well as DSA and OCT plaque characteristics, were analyzed for differences between symptomatic and asymptomatic cohorts. An analysis of logistic regression was carried out to identify factors associated with the presence of symptomatic carotid plaque. A multivariate binary logistic regression equation was established with the odds ratio (OR) serving as the risk assessment parameter. The receiver operating characteristic curve was utilized to assess the combined predictive model and independent influencing factors. A total of 52 patients were included in the study (symptomatic: 44.2%, asymptomatic: 55.8%). Symptomatic carotid stenosis was significantly linked to four main factors: low-density lipoprotein-cholesterol >3.36 mmol/L [OR, 6.400; 95% confidence interval (CI), 1.067-38.402; p = 0.042], irregular plaque (OR, 6.054; 95% CI, 1.016-36.083; p = 0.048), ruptured plaque (OR, 6.077; 95% CI, 1.046-35.298; p = 0.048), and thrombus (OR, 6.773; 95% CI, 1.194-38.433; p = 0.044). The combined predictive model generated using four indicators showed good discrimination (Area Under Curve, 0.924; 95% CI, 0.815-0. 979). The p value was <0.05 with 78.26% sensitivity and 93.10% specificity. OCT is valuable in evaluating the plaque characteristics of carotid atherosclerotic stenosis. The combined predictive model comprising low-density lipoprotein-cholesterol >3.36 mmol/L, irregular plaque, ruptured plaque, and thrombus could help in the detection of symptomatic carotid plaque. Further research conducted on additional independent cohorts is necessary to confirm the clinical significance of the predictive model for symptomatic carotid plaque.

Socioeconomic disparities in surgery for carotid artery disease in England.

Carotid artery disease and stroke are more prevalent in socioeconomically deprived areas. The aim was to investigate socioeconomic disparities in carotid artery disease surgery rates and in outcomes following surgery. The study used population-based ecological and cohort study designs, 31 672 census areas in England, hospital admissions from April 2006 to March 2018, the Index of Multiple Deprivation 2010 as the area-level deprivation indicator, and Poisson, logistic, and Cox regression. A total of 54 377 patients (67 per cent men) from a population aged 55 years and older of 14.7 million had carotid artery disease procedures (95 per cent carotid endarterectomy). Carotid endarterectomy rates were 116 per cent (95% c.i. 101 to 132) higher in men and 180 per cent (95% c.i. 155 to 207) higher in women aged 55-64 years in the most compared with the least socioeconomically deprived areas by quintile. However, this difference diminished and appeared to reverse with increasing age, with 24 per cent (95% c.i. 14 to 33) and 12 per cent (95% c.i. -3 to 24) lower carotid endarterectomy rates respectively in men and women aged 85 years and older in the most deprived areas. Patients in deprived areas having carotid endarterectomy were more likely to have been admitted as symptomatic emergency carotid artery disease admissions. Mortality, and a combined outcome of mortality or stroke-related re-admission, were both worse in patients living in more deprived areas and were only partially accounted for by the higher prevalence of co-morbidities. There was, however, no clear pattern of association between deprivation and elective waiting time for carotid endarterectomy. These results provide evidence of socioeconomic disparities in surgery for carotid artery disease. Clear policies are needed to address these disparities.

The influence of gender on 30-day adverse clinical outcomes in patients undergoing carotid surgery.

We aimed to further evaluate sex differences of perioperative and 30-day complications after carotid surgery in patients with both asymptomatic and symptomatic carotid artery stenosis. This was a single-center prospective cohort study including 2013 consecutive patients, who were treated surgically due to extracranial carotid artery stenosis and prospectively followed. Patients who underwent carotid artery stenting and who were treated conservatively were excluded. The primary endpoints for this study were hospital stroke/transitory ischemic attack (TIA) and overall survival rates. Secondary outcomes included all other hospital adverse events, 30-day stroke/TIA, and 30-day mortality rates. Hospital mortality was higher in female patients with symptomatic carotid stenosis (3% vs. 0.5%, P=0.018). Bleeding requiring re-intervention occurred more often in female patients with both asymptomatic (1.5% vs. 0.4%, P=0.045) and symptomatic carotid stenosis (2.4% vs. 0.2%, P=0.022). 30-day stroke/TIA and mortality rates were higher in female patients with both asymptomatic (stroke/TIA 4.4% vs. 2.5%, P=0.041; mortality 3.3% vs. 1.6%, P=0.046) and symptomatic carotid stenosis (stroke/TIA 8.3% vs. 4.2%, P=0.040; mortality 4.1% vs. 0.7%, P=0.006). After adjusting for all confounding factors, female gender remained an important predicting factor for 30-day stroke/TIA in asymptomatic (OR=1.4, 95%CI 1.0-4.7, P=0.041) and symptomatic patients (OR=1.7, 95%CI 1.1-5.3, P=0.040), as well as for 30-day all-cause mortality in patients with asymptomatic (OR=1.5, 95%CI 1.1-4.1, P=0.030) and symptomatic carotid artery disease (OR=1.2, 95%CI 1.0-5.2, P=0.048). Female gender is important predicting factor for stroke/TIA and all-cause mortality, both perioperative and during the first 30 days after carotid surgery.

Changes in intra- and extracranial carotid plaque calcification: a 2-year follow-up study

Extra- and intracranial carotid plaque calcification might have plaque-stabilizing effects, yet information on changes in plaque calcification remains scarce. We evaluated changes in carotid plaque calcification over 2 years follow-up in patients with symptomatic carotid artery disease. This study is based on the PARISK-study, a multicenter cohort study, with TIA/minor stroke patients with ipsilateral mild-to-moderate carotid artery stenosis (< 70%). We included 79 patients (25% female, mean age 66 years) who underwent CTA imaging with 2 year interval. We assessed the volume of extra- and intracranial carotid artery calcification (ECAC and ICAC) and calculated the difference between baseline and follow-up ECAC and ICAC volume. We performed multivariable regression analyses to investigate the association between change of ECAC or ICAC with cardiovascular determinants. ECAC. We found increase (46.2%) and decrease (34%) in ECAC volume during 2 year follow-up, both significantly correlation with baseline ECAC volume (OR = 0.72, 95% CI 0.58–0.90 respectively OR = 2.24, 95% CI 1.60–3.13).We found significant correlation for change in ECAC volume with diabetes (β = 0.46, 95% CI 0.03–0.89) and baseline ECAC volume (β = 0.81, 95% CI 0.73–0.88). ICAC. We found increase (45.0%) and decrease (25.0%) in ICAC volume. The ICAC decrease was significantly correlated with baseline ICAC volume (OR = 2.17, 95% CI 1.48–3.16), age (OR = 2.00, 95% CI 1.19–3.38) and use of antihypertensive drugs (OR = 3.79, 95% CI 1.20–11.96]).The overall change of ICAC volume was also significantly correlated with diabetes (β = 0.92, 95% CI 1.59–7.02), use of oral hypoglycemic drugs (β = 0.86, 95% CI 0.12–1.59) and baseline ICAC volume (β = 0.71, 95% CI 0.55–0.87). We provide novel insights into the dynamics of carotid plaque calcification in symptomatic stroke patients.

Early postoperative outcome after carotid artery endarterectomy with bifurcation advancement.

Background: The aim of this study is to review the single center experience in surgical treatment of carotid artery disease (CAD) using bifurcation advancement carotid endarterectomy (BA-CEA) and compare the in-hospital outcome with one of the largest nationwide carotid endarterectomy (CEA) databases worldwide, the German statutory quality assurance database (GD). Patients and methods: Data of BA-CEA procedures in the period of 2006-2015 were analyzed retrospectively. The primary endpoint was defined as combined stroke and death rate. Secondarily, isolated stroke, TIA, patient death, myocardial infarction, major neck hematoma and cranial nerve injuries were analyzed. Symptomatic and asymptomatic CAD patients were divided into two subgroups. The results were compared to extracted published data from the German database (GD). Results: Of 239 included BA-CEA procedures188 (78.7%) procedures were carried out in patients with symptomatic carotid artery stenosis. The overall perioperative combined stroke and death rate after BA-CEA was 2.5%.Five (2.1%) patients suffered from a stroke (one minor and four major strokes), of which two hemorrhagic strokes ended fatally. Overall, four (1.7%) patients died perioperatively. The combined stroke and death rate was higher in the symptomatic subgroup (3.2%; 0% in the asymptomatic group). No significant differences were found between the results of BA-CEA and the German database (n=142'074) for combined stroke and death rates and isolated stroke. Significant differences were found among the overall mortality rate (BA-CEA: 1.7% vs. GD: 0.6, p=0.04). The risk of postoperative cranial nerve injuries was also significantly higher after BA-CEA overall (BA-CEA: 5.0% vs. GD: 1.2%, p=<0.0001), in symptomatic CAD patients (BA-CEA: 4.8% vs. GD: 1.2%, p=<0.0001) and in asymptomatic CAD patients (BA-CEA: 5.9% vs. GD: 1.3%, p=0.01). Conclusions: CEA with bifurcation advancement provides comparable perioperative results, focusing on combined stroke and mortality, but seems to have some technical drawbacks, which may lead to more frequent local neurological complications.

Shear Wave Elastography for the Assessment of Carotid Plaque Vulnerability: A Systematic Review

Evidence for the management of asymptomatic carotid stenosis and possibly symptomatic nonstenosing carotid artery disease is limited. In contrary to calcified plaques, soft plaques are considered vulnerable and prone to rupture. Shear wave elastography (SWE), a novel ultrasound technique which uses acoustic wave force to propagate shear wave in tissues, can quantify tissue stiffness through the estimation of Young’s modulus (YM) in kPa or shear wave velocity in meter/second. This systematic review is aimed at evaluating the feasibility of SWE in carotid plaque risk stratification in relation to ischemic stroke (PROSPERO registration: CRD42022309709). 18 studies, obtained via search on PubMed, Cochrane, and Embase from inception until November 1, 2022, assessed SWE’s feasibility in carotid plaque risk stratification in humans (13 studies) and phantom models (5 studies). Human studies showed heterogeneity with respect to SWE devices, acquisition settings, and methodology, which consequently reflected in the between-study variability of YM values used for distinguishing vulnerable/symptomatic (27–52 kPa) and stable/asymptomatic (28–115 kPa) carotid plaques. However, within-study assessment of all human studies indicated SWE’s feasibility in carotid plaque risk stratification. Furthermore, four out of five carotid plaque phantom studies showed the potential of SWE to discriminate tissues of different stiffness comparable to the carotid vessel wall, soft and hard plaques, and with good reproducibility. SWE may potentially offer a bedside risk stratification tool for identifying patients with vulnerable carotid plaques, who may benefit from carotid surgery, stenting, or prolonged dual antiplatelet therapy. Patients with stable carotid plaques could be spared the risks of potentially harmful treatments and complications. However, available data are not enough to facilitate the immediate clinical application of SWE, and therefore, larger prospective clinical are warranted.

390 Real World Analysis of Outcomes After Revascularization Surgery for Symptomatic Non-stenotic Carotid (SyNC) Artery Disease

INTRODUCTION: Symptomatic non-stenotic carotid (SyNC) artery disease is emerging as one of the primary causes of embolic stroke of unknown source. The optimal secondary prevention strategies including medical therapy and revascularization (Carotid Endarterectomy (CEA) versus Carotid Artery Stenting (CAS)) continue to be controversial. METHODS: The National Surgical Quality Improvement Program (NSQIP) targeted dataset for CEA and CAS was queried for symptomatic patients with &lt;50% stenosis of the ipsilateral carotid artery undergoing CEA and CAS between 2012-2019. Data analysis for continuous and categorical variables was carried out. RESULTS: A total of 363 symptomatic patients with &lt;50% stenosis of the ipsilateral carotid artery were identified of which 22 underwent CAS and 341 underwent CEA. Statistical analysis showed that patients undergoing CEA were more likely to be male as compared to those undergoing CAS (68% vs 54.5%, p &lt; 0.001). Additionally, patients in the CAS group were more likely to present with high-risk anatomy features compared to patients in the CEA group (31.8% vs 11.7%, p = 0.007) whereas patients undergoing CEA were more likely to have &lt;50% stenosis contralateral ICA stenosis when compared to patients undergoing CAS (65.1% vs 36.4%, p = 0.001). Furthermore, patients undergoing CAS were more likely to experience post procedural stroke at 30 days compared to those undergoing CEA (13.6% vs 3.8%, p = 0.03). Upon multivariable analysis, CEA was associated with lower odds of post procedural stroke as compared to CAS (OR = 0.17, 95% CI 0.033-0.82, p = 0.027). CONCLUSIONS: Carotid revascularization for SyNC is being performed despite current guidelines and CEA is associated with lower odds of post-procedural stroke compared to CAS.

392 A Morphological Study of Non-Stenotic Carotid Atheromas Causing Recurrent Strokes: Chronicle of Disruption and Stabilization

INTRODUCTION: Symptomatic non-stenotic carotid (SyNC) artery disease is a recognized etiology of ischemic strokes with a putative thromboembolic mechanism. To date, the structural phenotypes expressed at the lumen/wall interface of these lesions are not completely understood resulting in misdiagnosis and hindering the development of targeted therapies. METHODS: After IRB approval, en block endarterectomy specimen were obtained from patients with recurrent strokes from SyNC (n=9). Additionally, segments of superficial temporal artery (STA) of patients undergoing cerebral artery bypass surgeries were obtained as controls (n=3). The endovascular surfaces of the samples were imaged with laser microangioscopy and scanning electron microscopy (SEM). Images were benchmarked with histological sections and immunohistochemistry (IHC). RESULTS: Normal endothelial surfaces in STA were light pink, smooth and homogenous by angioscopy with typical cobblestone endothelial pattern. Features recognized as those associated with plaque disruption and thrombosis were de-endothelialization, inflammatory infiltrates within and under the endothelium, delamination (flaps oriented to the flow) with superficial intimal hemorrhages, plaque erosion and disruption of the fibrous cap with fissuring, ulceration, excavation and plaque hemorrhage. Additionally, cellular and acellular structures actively involved in plaque stabilization, seen on SEM and confirmed with histology and IHC, were also identified including activated platelets, fibrin band, bridges and webs, neutrophil extracellular traps and endothelial progenitor cells. CONCLUSIONS: This ultrastructural study of the vascular surface of SyNC specimens reveals concurrent phenotypes of flow-dependent disruption and stabilization that could become new imaging biomarkers and enable the development of targeted therapies.

Quantification of new intracerebral lesions on diffusion-weighted magnetic resonance imaging after transcarotid artery revascularization for treatment of carotid artery stenosis

Transcarotid artery revascularization (TCAR) has been used with increasing prevalence for treatment of carotid artery stenosis. TCAR holds potential benefits over traditional carotid endarterectomy (CEA) or transfemoral carotid artery stenting by its nature of being less invasive than CEA but more neuroprotective than transfemoral carotid artery stenting. The purpose of this pilot study is to evaluate the effectiveness of the neuroprotection system of TCAR with flow reversal by quantifying the incidence and degree of new intracerebral lesions using diffusion-weighted magnetic resonance imaging (DW-MRI). This study is the first to evaluate these findings in a real-world, high-risk cohort, who would have been excluded from the ROADSTER and ENROUTE transcarotid neuroprotection system DW-MRI studies. Patients undergoing unilateral TCAR for symptomatic or asymptomatic severe internal carotid artery disease were eligible and prospectively enrolled in the study. All patients had high risk features, including comorbidities or medications, which excluded them from industry-sponsored DW-MRI trials. Patients underwent a preoperative DW-MRI to obtain a baseline intracerebral evaluation within 1 week of the scheduled surgery. The follow-up DW-MRI occurred within 48hours postoperatively. The primary outcome was new, acute postoperative lesion(s) identified on DW-MRI. Secondary outcomes include any major stroke, myocardial infarction, or death during hospitalization. Five consecutive patients underwent TCAR with preoperative and postoperative imaging. All five patients were on dual antiplatelet therapy before their procedure and verified to be therapeutic on these agents. All patients underwent a right-sided TCAR and three were symptomatic as the indication for their procedure. All five patients demonstrated chronic lesions on the preoperative DW-MRI. Technical success was achieved in all five patients, with one operative complication involving a dissection of the common carotid at the access site, which was stented using the TCAR system. Postoperative DW-MRI did not identify any new intracerebral lesions in any patient following the procedure. No patient had a stroke, myocardial infarction, or death during hospitalization. In this real-world, high-risk cohort, TCAR was completed with no evidence of new, postoperative DW-MRI lesions. These data further demonstrate that TCAR with flow reversal is an effective neuroprotective strategy for carotid revascularization. Further study is warranted to evaluate DW-MRI differences between TCAR and CEA.

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.

Atherosclerotic Carotid Artery Disease: Where to from the emergency room? University hospital experience.

Stroke is the second leading cause of death worldwide, resulting in 5.5 million deaths in 2016. Vascular interventions, including carotid endarterectomy (CEA) and carotid artery stenting, play a major role in stroke prevention, especially when performed early after onset of symptoms. This study aimed to define the role of vascular surgeons in ischaemic stroke management and hence improve referral patterns by creating an algorithm for the referral process. This could reduce time to intervention and optimise patient benefit from intervention. This retrospective study reviewed symptomatic and asymptomatic patients with atherosclerotic disease of the carotid artery who were referred to the Vascular Surgery Unit of Sultan Qaboos University Hospital, Muscat, Oman, from April 2018 to March 2020 to examine factors influencing recognition of suitable candidates for intervention. Following analysis of the data, algorithms/protocols were created to simplify the referral process of symptomatic and asymptomatic carotid artery disease for surgical intervention. A total of 38 patients with ischaemic stroke were recognised as having carotid artery stenosis and were referred to the vascular surgery service during the study period. Only six met the criteria for CEA, four of which underwent the procedure. Choice of patients for CEA involves multiple steps, with potential for missed opportunities. By involving a multidisciplinary team approach, the recommended protocol aims to lead to early and appropriate referral to a vascular surgeon or an interventional radiologist, resulting in increased and optimised intervention in stroke prevention.

Quantification of New Intracerebral Lesions on Diffusion-weighted Magnetic Resonance Imaging After Transcarotid Artery Revascularization for Treatment of Carotid Stenosis

Quantification of New Intracerebral Lesions on Diffusion-weighted Magnetic Resonance Imaging After Transcarotid Artery Revascularization for Treatment of Carotid Stenosis

Changes in intra- and extracranial carotid plaque calcification: A two-year follow-up study

Background and Aims : Extra- and intracranial carotid plaque calcification has gained rapid interest given its potential plaque-stabilizing effects, yet information on temporal changes in plaque calcification remains scarce. Hence, we evaluated changes in carotid plaque calcification over two years follow-up in patients with symptomatic carotid artery disease.

Extracranial-to-Intracranial Bypass for Distal Internal Carotid Artery and/or Proximal Middle Cerebral Artery Steno-Occlusive Disease: A Case Series of Clinical Outcomes at a Single, High-Volume Cerebrovascular Center.

Extracranial-to-intracranial (EC-IC) bypass was first described by Yasargil in the 1960s for treatment of symptomatic distal internal carotid artery (ICA) and/or proximal middle cerebral artery (MCA) steno-occlusive disease through direct anastomosis. Subsequent bypass trials failed to demonstrate benefit for overall outcomes and stroke rates compared with best medical therapy. However, the procedure remained in the neurosurgeon's armament, with studies showing benefits in select patient populations. With advancements in technology, patient selection has become more comprehensive. To provide a contemporary evaluation of EC-IC bypass from our high-volume cerebrovascular center, focusing on associated clinical outcomes. Consecutive patients who underwent direct EC-IC bypass surgeries for symptomatic distal ICA and/or proximal MCA steno-occlusive disease between April 2015 and September 2019 were identified retrospectively. Medical records were reviewed to collect demographics, clinical presentation, computed tomography perfusion imaging findings, transcranial Doppler results, procedure indication, donor vessel types, anastomosis site, bypass patency, periprocedural complications, postprocedural complications, symptom recrudescence, repeat or new interventions, subjective improvements, and modified Rankin Scale scores. We identified 27 patients who underwent 32 EC-IC bypass procedures. The rate of ipsilateral stroke was 9.4%, with a median follow-up of 8 months (IQR, 4-13 months). Patients experienced a 22.3% improvement in modified Rankin Scale scores, and 70.3% of patients reported subjective improvement and satisfaction at follow-up. Direct EC-IC bypass remains a viable option for revascularization in symptomatic patients with distal ICA and/or proximal MCA steno-occlusive disease.