Intracranial Large and Medium Artery Atherosclerotic Disease and Stroke

Mendelian Randomization Study Investigating the Causal Relationship Between Thyroid Dysfunction and Cerebral Infarction

BACKGROUND

There is an association between thyroid dysfunction and cerebral infarction (CI), but the causality cannot be determined. A two-sample two-way Mendelian randomization (MR) study was conducted to assess the causal relationship between thyroid function and CI.

METHODS

We selected single-nucleotide polymorphisms (SNPs) associated with five phenotypes, including CI from the UK Biobank (n = 361,194), hyperthyroidism from the IEU Open GWAS database (n = 484,598), hypothyroidism from the IEU Open GWAS database (n = 473,703), normal thyroid-stimulating hormone (TSH) (n = 271,040), and normal free thyroxine (FT4) (n = 119,120) from the Thyroidomics Consortium database. For the forward MR analysis, the exposures were hyperthyroidism, hypothyroidism, TSH, and FT4. The inverse variance weighted (IVW) method, weighted median (WM), and MR-Egger revealed the causality with CI. For the reverse MR analysis, CI was regarded as the exposure, and four thyroid function phenotypes were the outcomes. The sensitivity and heterogeneity test was assessed using Cochran's Q test, MR-Egger regression, and leave-one-out analysis.

RESULTS

The MR analysis indicated that genetic susceptibility to hyperthyroidism increased the risk of CI (IVW-OR = 1.070; 95% CI: 1.015-1.128; p = 0.003). In reverse MR, genetic susceptibility to RA is not associated with hyperthyroidism (IVW-OR = 1.001; 95% CI: 1.000-1.001; p = 0.144). Any positive or reverse causal relationship between hypothyroidism, FT4, and TSH with CI could not be established. Sensitivity and heterogeneity test consolidated our findings.

CONCLUSION

The causality between CI and hyperthyroidism demonstrated patients with hyperthyroidism have a risk of genetic variants for CI. In the future, further studies are needed to fully explore their mechanisms of action.

Prevalence, diagnosis and management of intracranial atherosclerosis in White populations: a narrative review

BACKGROUND

Intracranial atherosclerotic disease (ICAD) represents a leading cause of ischemic stroke worldwide, conferring increased risk of recurrent stroke and poor clinical outcomes among stroke survivors. Emerging evidence indicates a paradigm shift, pointing towards increasing detection rates of ICAD among White populations and an evolving epidemiological profile across racial and ethnic groups. The present review aims to provide a comprehensive overview of ICAD, focusing on its pathophysiology, diagnostic approach, and evolving epidemiological trends, including underlying mechanisms, advanced neuroimaging techniques for diagnostic evaluation, racial disparities in prevalence, and current and emerging management strategies.

MAIN BODY

Atherosclerotic plaque accumulation and progressive arterial stenosis of major intracranial arteries comprise the pathophysiological hallmark of ICAD. In clinical practice, the diagnosis of intracranial artery stenosis (ICAS) or high-grade ICAS is reached when luminal narrowing exceeds 50% and 70%, respectively. Advanced neuroimaging, including high-resolution vessel wall MRI (HRVW-MRI), has recently enabled ICAD detection before luminal stenosis occurs. While earlier studies disclosed significant racial disparities in ICAS prevalence, with higher rates among Asians, Hispanics, and Blacks, recent evidence reveals rising detection rates of ICAD among White populations. Genetic, environmental and epigenetic factors have been suggested to confer an increased susceptibility of certain ethnicities and races to ICAD. Nevertheless, with improved accessibility to advanced neuroimaging, ICAD is increasingly recognized as an underlying stroke etiology among White patients presenting with acute ischemic stroke and stroke of undetermined etiology. While conventional management of ICAS entails risk factor modification, pharmacotherapy, and endovascular treatment in selected high-risk patients, substantial progress remains to be made in the management of ICAD at its early, pre-stenotic stages.

CONCLUSION

ICAD remains a critical yet underappreciated risk factor for ischemic stroke across all populations, highlighting the need for increased awareness and improved diagnostic strategies. The emerging epidemiological profile of ICAD across racial groups necessitates a reassessment of risk factors, screening protocols and preventive strategies. Future research should focus on refining the diagnostic criteria and expanding the therapeutic options to cover the full spectrum of ICAD, with the aim of improving patient outcomes and reducing the global burden of intracranial atherosclerosis and stroke.

Emergent Large Vessel Occlusion due to Intracranial Stenosis: Identification, Management, Challenges, and Future Directions

This comprehensive literature review focuses on acute stroke related to intracranial atherosclerotic stenosis (ICAS), with an emphasis on ICAS-large vessel occlusion. ICAS is the leading cause of stroke globally, with high recurrence risk, especially in Asian, Black, and Hispanic populations. Various risk factors, including hypertension, diabetes, hyperlipidemia, smoking, and advanced age lead to ICAS, which in turn results in stroke through different mechanisms. Recurrent stroke risk in patients with ICAS with hemodynamic failure is particularly high, even with aggressive medical management. Developments in advanced imaging have improved our understanding of ICAS and ability to identify high-risk patients who could benefit from intervention. Herein, we focus on current management strategies for ICAS-large vessel occlusion discussed, including the use of perfusion imaging, endovascular therapy, and stenting. In addition, we focus on strategies that aim at identifying subjects at higher risk for early recurrent risk who could benefit from early endovascular intervention The review underscores the need for further research to optimize ICAS-large vessel occlusion treatment strategies, a traditionally understudied topic.

Multimodal imaging approach for the diagnosis of intracranial atherosclerotic disease (ICAD): Basic principles, current and future perspectives

PURPOSE

To review the different imaging modalities utilized in the diagnosis of Intracranial Atherosclerotic Disease (ICAD) including their latest development and relevance in management of ICAD.

METHODS

A review of the literature was conducted through a search in google scholar, PubMed/Medline, EMBASE, Scopus, clinical trials.gov and the Cochrane Library. Search terms included, "imaging modalities in ICAD," "ICAD diagnostic," "Neuroimaging of ICAD," "Evaluation of ICAD". A summary and comparison of each modality's basic principles, advantages and disadvantages were included.

RESULTS

A total of 144 articles were identified and reviewed. The most common imaging used in ICAD diagnoses were DSA, CTA, MRA and TCD. They all had proven accuracy, their own benefits, and limitations. Newer modalities such as VWI, IVUS, OCT, PWI and CFD provide more detailed information regarding the vessel walls, plaque characteristics, and flow dynamics, which play a tremendous role in treatment guidance. In certain clinical scenarios, using more than one modality has been shown to be helpful in ICAD identification. The rapidly evolving software related to imaging studies, such as virtual histology, are very promising for the diagnostic and management of ICAD.

CONCLUSIONS

ICAD is a common cause of recurrent ischemic stroke. Its management can be both medical and/or procedural. Many different imaging modalities are used in its diagnosis. In certain clinical scenario, a combination of two more modalities can be critical in the management of ICAD. We expect that continuous development of imaging technique will lead to individualized and less invasive management with adequate outcome.

Elevated RANTES levels are associated with increased risk of cerebral atherosclerotic stenosis

BACKGROUND

Cerebral atherosclerotic stenosis (CAS) is a significant factor in the development of acute ischemic stroke (AIS). Previous studies have reported that cytokines are involved in atherosclerotic diseases, although the relationship between serum levels of the chemokine RANTES (regulated on activation, normal T-cell expressed and secreted) and the presence of CAS remains unclear.

METHODS

In total, 127 participants (65 non-AIS controls and 62 patients with AIS) were involved in this study. CAS was defined as the presence of ≥ 50% stenosis in major intracranial or extracranial artery by a Digital Substraction Angiography (DSA) examination, and we classified all participants into four groups according to stroke and CAS status. Serum concentrations of 8 cytokines, including RANTES, were measured by the Human ProcartaPlex Multiplex Immunoassay Kit.

RESULTS

Seventy-eight participants (61.41%) had CAS, of which 39 cases with AIS and 39 case with non-AIS. Patients with CAS had higher RANTES levels compared to non-CAS patients in both the non-AIS group (10.54 ± 0.80 vs. 13.20 ± 0.71, p = 0.016) and stroke group (11.96 ± 0.87 vs. 15.03 ± 0.75, p = 0.011), and multivariate logistic regression analysis showed that the RANTES level is independently associated with CAS in both the non-AIS group (adjusted odds ratio (OR), 1.07; 95% CI, 1.02-1.12, P = 0.004) and stroke group (adjusted OR, 1.32; 95% CI, 1.10-1.58, P = 0.003).

CONCLUSION

Patients with CAS have higher levels of serum RANTES than non-CAS patients regardless of stroke status suggesting that RANTES may play an important role in the formation of CAS.

Relationship between the stroke mechanism of symptomatic middle cerebral artery atherosclerotic diseases and culprit plaques based on high-resolution vessel wall imaging

Purpose

For patients with symptomatic middle cerebral artery (MCA) atherosclerotic stenosis, identifying the potential stroke mechanisms may contribute to secondary prevention. The purpose of the study is to explore the relationship between stroke mechanisms and the characteristics of culprit plaques in patients with atherosclerotic ischemic stroke in the M1 segment of the middle cerebral artery (MCA) based on high-resolution vessel wall imaging (HR-VWI).

Methods

We recruited 61 patients with acute ischemic stroke due to MCA atherosclerotic stenosis from Shenzhen Bao'an District People's Hospital. According to prespecified criteria based on infarct topography and magnetic resonance angiography, possible stroke mechanisms were divided into parent artery atherosclerosis occluding penetrating artery (P), artery-to-artery embolism (A), hypoperfusion (H), and mixed mechanisms (M). The correlation between the characteristics of MCA M1 culprit plaque and different stroke mechanisms was analyzed using HR-VWI. The indicators included plaque surface irregularity, T1 hyperintensity, location, plaque burden (PB), remodeling index (RI), enhancement rate, and stenosis rate.

Results

Parental artery atherosclerosis occluding penetrating artery was the most common mechanism (37.7%). The proposed criteria showed substantial to excellent interrater reproducibility (κ, 0.728; 0.593–0.863). Compared with the P group, the surface irregularity, T1 hyperintensity, and obvious enhancement of the culprit plaque in the A group were more common (p < 0.0125). Compared with the other stroke mechanisms, positive remodeling of culprit plaques was more common (p < 0.0125), the RI was greater (p < 0.05), and the PB was the smallest (p < 0.05) in the P group. The enhancement ratio (ER) was smaller in the P group (p < 0.05). Compared with the A group, T1 hyperintensity of the culprit plaque was more common in the H group (p < 0.0125), and the stenosis rate was greater (p < 0.05). After adjustment for clinical demographic factors in the binary logistic regression analysis, the enhancement level (odds ratio [OR] 0.213, 95% CI (0.05–0.91), p = 0.037) and PB of culprit plaque (OR 0, 95% CI (0–0.477), p = 0.034) were negatively associated with P groups.

Conclusion

The culprit plaque characteristics of patients with symptomatic MCA atherosclerotic in different stroke mechanisms may be evaluated using HR-VWI. The plaque characteristics of different stroke mechanisms may have clinical value for the selection of treatment strategies and prevention of stroke recurrence.

Clinical trial registration

Identifier: ChiCTR1900028533.

Mechanical Thrombectomy with or without Intravenous Thrombolysis in Acute Ischemic Stroke: A Meta-Analysis for Randomized Controlled Trials

INTRODUCTION

The combination of mechanical thrombectomy (MT) and intravenous thrombolysis (IVT) is more effective than IVT alone in patients with large vessel occlusion, which has been proven in recent studies. However, there are still debates over whether IVT benefits patients treated with only direct mechanical thrombectomy (dMT).

METHODS

PubMed, Embase, and Cochrane Library were searched on June 15, 2021, for randomized controlled trials (RCTs). Seven RCTs with 2,143 patients were enrolled in our study.

RESULTS

MT combined with IVT had comparable efficacy and safety outcome compared with dMT in proximal anterior circulation occlusion at 90 days. For the primary outcome, pooled data showed no significant difference in the modified Rankin Scale (mRS) 0-2 at 90 days between the dMT and MT+IVT groups (pooled odds ratio 0.96, 95% confidence interval, 0.79, 1.17, p = 0.39). As for the mRS score 0-1 at 90 days, the degree of benefit conferred by dMT was substantial: for every 100 patients treated, the number of patients which had an excellent outcome in the dMT group was 10 higher than that of the MT+IVT group.

CONCLUSION

In this meta-analysis including 7 RCTs, MT had comparable consequences to bridging treatment in efficacy and safety outcomes for patients with ischemic stroke caused by the occlusion of proximal anterior circulation, irrespective of geographical location. These findings support the adoption of dMT in acute ischemic stroke treatments and have higher cost-effectiveness in global applications.

Rescue Endovascular Treatment for Emergent Large Vessel Occlusion With Underlying Intracranial Atherosclerosis: Current State and Future Directions

Intracranial atherosclerosis (ICAS) is one of the most common causes of stroke worldwide and is associated with high risk of stroke recurrence. While the most common clinical presentation is acute–subacute transient ischemic attack or ischemic stroke, occasionally, patients with underlying ICAS present with acute occlusion of the affected vessel. Diagnosis and endovascular management of ICAS-related emergent large vessel occlusion (ELVO) can be challenging. Herein, we review the current evidence supporting endovascular management of ICAS-related ELVO and discuss future directions.

Outcomes of Rescue Endovascular Treatment of Emergent Large Vessel Occlusion in Patients With Underlying Intracranial Atherosclerosis: Insights From STAR

Background

Some emergent large vessel occlusions (ELVOs) are refractory to reperfusion because of underlying intracranial atherosclerosis (ICAS), often requiring rescue therapy (RT) with balloon angioplasty, stenting, or both. In this study, we investigate the safety, efficacy, and long‐term outcomes of RT in the setting of mechanical thrombectomy for ICAS‐related ELVO.

Methods and Results

We queried the databases of 10 thrombectomy‐capable centers in North America and Europe included in STAR (Stroke Thrombectomy and Aneurysm Registry). Patients with ELVO who underwent ICAS‐related RT were included. A matched sample was produced for variables of age, admission National Institute of Health Stroke Scale, Alberta Stroke Program Early CT Score, onset to groin puncture time, occlusion site, and final recanalization. Out of 3025 patients with MT, 182 (6%) patients required RT because of underlying ICAS. Balloon angioplasty was performed on 122 patients, and 117 patients had intracranial stenting. In the matched analysis, 141 patients who received RT matched to a similar number of controls. The number of thrombectomy passes was higher (3 versus 1, P<0.001), and procedural time was longer in the RT group (52 minutes versus 36 minutes, P=0.004). There was a higher rate of symptomatic hemorrhagic transformation in the RT group (7.8% versus 4.3%, P=0.211), however, the difference was not significant. There was no difference in 90‐day modified Rankin scale of 0 to 2 (44% versus 47.5%, P=0.543) between patients in the RT and control groups.

Conclusions

In patients with ELVO with underlying ICAS requiring RT, despite longer procedure time and a more thrombectomy passes, the 90 days favorable outcomes were comparable with patients with embolic ELVO.

Neutrophil-to-lymphocyte ratio predicts early worsening in stroke due to large vessel disease

Background

Inflammation plays an important role in atherosclerosis and its complications. Since a dysregulated inflammatory response is associated with early neurological deterioration (END), serum neutrophil-to-lymphocyte ratio (NLR) could be a marker of END as well.

Aim

In this study, we evaluated the relationship between the serum NLR and END in patients with ischemic stroke due to large-artery atherosclerosis (LAA).

Methods

We evaluated consecutive patients with ischemic stroke due to LAA between January 2010 and December 2015. END was defined as an increase ≥ 2 on the total NIHSS score or ≥ 1 on the motor NIHSS score within the first 72 hours of admission. The NLR was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count.

Results

Of the 349 included patients, 18.1% (n = 63) had END events. In multivariate analysis, serum NLR was independently associated with END (adjusted odds ratio, 1.08; 95% confidence interval [1.00–1.16], P = 0.043). Time to admission, and in-situ thrombosis and artery-to-artery embolization mechanisms were also significantly associated with END events. In an analysis of the relationship between serum NLR and vascular lesion burden, serum NLR was positively correlated with both the degree of stenotic lesions (P for trend = 0.006) and the number of vessel stenosis (P for trend = 0.038) in a dose-response manner. We also compared serum NLR by the stroke mechanisms: patients with hypoperfusion or in-situ thrombosis had the highest levels of NLR: however, only those with in-situ thrombosis had significantly higher NLR in the END group compared to the non-END group (P = 0.005).

Conclusions

Serum NLR levels were associated with END events in patients with ischemic stroke due to LAA. Since NLR was also closely correlated with the underlying vascular lesions, our results indicated clues for mechanisms of END events.

Relationship Between Asymptomatic Intracranial Stenosis and Extracranial Arteriosclerotic Findings in Workplace Health Checkups: A Pilot Study

BACKGROUND

Intracranial arteriosclerotic disease (ICAD) is common in Asians and has been presumed to be largely associated with metabolic syndrome (MetS), but the risks for asymptomatic ICAD detectable in examinations of the brain, among other tests, are not well known. The present study is aimed at identifying the risks for asymptomatic ICAD using data on risk factors obtained in health checkups, including data from magnetic resonance imaging (MRI), chest computed tomography (CT), and neck echography.

METHODS

Subjects comprised 103 examinees more than equal to 40 years old (56.9 ± 4.7 years, 93 men) who underwent head MRI, chest CT, and carotid echography in the same period in a workplace health checkup between April and September 2014. Subjects were evaluated for ICAD based on stenosis of bilateral middle cerebral arteries and the basilar artery on previously reported scores from magnetic resonance angiography. Evaluations for extracranial arteriosclerotic disease (ECAD) were based on findings from carotid echography, and total calcium scores were calculated based on the number, areas, and peak Hounsfield computed tomographic numbers of the aortic arch calcified lesion detected.

RESULTS

ICAD, including mild cases with stenosis less than 50%, was seen in 21 subjects (20.3%); and MetS was evident in 12 subjects (11.7%). Logistic regression analysis with multivariate adjustment for major vascular risk factor demonstrated that echogenic of plaque was significantly associated with the ICAD (OR 3.69, 95%CI 1.02-13.3), however age was significant predictor of the risk profile in patients with ECAD.

CONCLUSIONS

Carotid atherosclerosis could predict intracranial atherosclerosis in middle-aged people. However, further study with large sample size is warranted.

Distribution of atherosclerotic lesions in various arteries of WHHLMI rabbits, an animal model of familial hypercholesterolemia

In WHHLMI rabbits, arterial lesions develop spontaneously in various arteries even with standard chow. Here, we examined the development of arterial lesions in various arteries to demonstrate standard characteristics of arterial lesions in WHHLMI rabbits. For WHHLMI rabbits at 6, 12, 20, and 30 months of age, lesion areas and areas of arterial lumen surfaces were measured using image analysis software. Histopathological sections of arterial lesions were stained with elastic van Gieson staining. Arterial lesions developed around bifurcations and expanded with aging. In the aorta, atheromatous lesions were severe in the thoracic aorta but were mild in the distal part of the abdominal aorta. Carotid artery lesions progressed in the proximal region and at bifurcations, and the histopathological features were similar to those of coronary lesions. Pulmonary artery lesions contained many foam cells. Fibrous lesions were observed in the proximal and distal areas of the renal arteries, at the bifurcation of the iliac-femoral artery and mesenteric artery, and around the anastomosis of vertebral arteries. Lesions in the celiac artery contained foam cells and/or lipid droplets within fibrous lesions. In a pair of right and left arteries, the arterial lesions tended to progress more in the right artery. Gender did not affect analysis of arterial lesions. In conclusion, the arterial lesions expanded from bifurcations, and the morphological features of the arterial lesions varied depending on the type of artery. These results serve as reference data for arterial lesions in studies using WHHLMI rabbits.