Prevalence and prognosis of coexistent asymptomatic intracranial stenosis

Prognostic Value of Mild Asymptomatic Intracranial Atherosclerotic Stenosis in Patients With Hypertension

BACKGROUND

Mild asymptomatic intracranial atherosclerotic stenosis (aICAS) is common in Chinese patients with hypertension. However, there are no data on its prognostic value in this population. The aim of the present study was to clarify the prevalence and associated cardiovascular risk factors of mild aICAS and determine its prognostic value for overall and cardiovascular mortality in patients with hypertension.

METHODS

In total, 1,813 participants were evaluated for aICAS using computed tomographic angiography. The predictive effect of mild to severe aICAS on all-cause and cardiovascular mortality was evaluated using Kaplan-Meier survival curves and Cox regression analyses.

RESULTS

The prevalence rate of mild aICAS was 35.7%. Poorly controlled hypertension, in combination with diabetes and dyslipidemia, was associated with aICAS. Patients with aICAS had an independently significant increase in the risk of all-cause and cardiovascular death, with adjusted hazard ratios (HRs) for mild to severe stenosis ranging from 1.56 to 3.30 for all-cause death and from 2.48 to 6.38 for cardiovascular death. Among the patients with mild aICAS, only those with more than two stenoses had increased mortality after adjustment, with an HR of 2.44 (95% CI: 1.42-4.18) for total death and 4.49 (95% CI: 1.82-11.05) for cardiovascular death.

CONCLUSIONS

A significant association between mild aICAS and mortality in stroke-free patients with hypertension was revealed. The results indicate that mild aICAS might be an imaging marker for cerebrovascular lesions in patients with hypertension and poor control of blood pressure and lipids in this population requires further research.

Development and validation of a SCORing systEm for pre-thrombectomy diagnosis of IntraCranial Atherosclerotic Disease (Score-ICAD)

BACKGROUND

Early identification of intracranial atherosclerotic disease (ICAD) may impact the management of patients undergoing mechanical thrombectomy (MT). We sought to develop and validate a scoring system for pre-thrombectomy diagnosis of ICAD in anterior circulation large vessel/distal medium vessel occlusion strokes (LVOs/DMVOs).

METHODS

Retrospective analysis of two prospectively maintained comprehensive stroke center databases including patients with anterior circulation occlusions spanning 2010-22 (development cohort) and 2018-22 (validation cohort). ICAD cases were matched for age and sex (1:1) to non-ICAD controls.

RESULTS

Of 2870 MTs within the study period, 348 patients were included in the development cohort: 174 anterior circulation ICAD (6% of 2870 MTs) and 174 controls. Multivariable analysis β coefficients led to a 20 point scale: absence of atrial fibrillation (5); vascular risk factor burden (1) for each of hypertension, diabetes, smoking, and hyperlipidemia; multifocal single artery stenoses on CT angiography (3); absence of territorial cortical infarct (3); presence of borderzone infarct (3); or ipsilateral carotid siphon calcification (2). The validation cohort comprised 56 ICAD patients (4.1% of 1359 MTs): 56 controls. Area under the receiver operating characteristic curve was 0.88 (0.84-0.91) and 0.82 (0.73-0.89) in the development and validation cohorts, respectively. Calibration slope and intercept showed a good fit for the development cohort although with overestimated risk for the validation cohort. After intercept adjustment, the overestimation was corrected (intercept 0, 95% CI -0.5 to -0.5; slope 0.8, 95% CI 0.5 to 1.1). In the full cohort (n=414), ≥11 points showed the best performance for distinguishing ICAD from non-ICAD, with 0.71 (95% CI 0.65 to 0.78) sensitivity and 0.82 (95% CI 0.77 to 0.87) specificity, and 3.92 (95% CI 2.92 to 5.28) positive and 0.35 (95% CI 0.28 to 0.44) negative likelihood ratio. Scores ≥12 showed 90% specificity and 63% sensitivity.

CONCLUSION

The proposed scoring system for preprocedural diagnosis of ICAD LVOs and DMVOs presented satisfactory discrimination and calibration based on clinical and non-invasive radiological data.

Recurrent stroke risk in intracranial atherosclerotic disease

Recurrent stroke risk secondary to intracranial atherosclerotic disease remains high despite aggressive medical treatment. This risk is further amplified in subgroups possessing biomarkers of hemodynamic insufficiency and potential for embolization, which have been shown to be independently and synergistically predictive of recurrent stroke. Luminal stenosis was predominantly used as entry criteria in major treatment trials, discounting the potential role of hemodynamics from primary analyses, limiting the strength of evidence and conclusions of these biomarkers to post-hoc analyses and other natural history studies. Future treatment trials should consider stratifying patients using a combination of these high-risk biomarkers. In the absence of trials, risk stratifying patients based on the presence of these markers may lend to more individualized clinical decisions. We aimed to summarize the studies that have investigated the relationship between biomarkers and their role in predicting recurrent stroke risk in intracranial atherosclerotic disease.

Identification of high-risk intracranial plaques with 3D high-resolution magnetic resonance imaging-based radiomics and machine learning

BACKGROUND

Identifying high-risk intracranial plaques is significant for the treatment and prevention of stroke.

OBJECTIVE

To develop a high-risk plaque model using three-dimensional (3D) high-resolution magnetic resonance imaging (HRMRI) based radiomics features and machine learning.

METHODS

136 patients with documented symptomatic intracranial artery stenosis and available HRMRI data were included. Among these patients, 136 and 92 plaques were identified as symptomatic and asymptomatic plaques, respectively. A conventional model was developed by recording and quantifying the radiological plaque characteristics. Radiomics features from T1-weighted images (T1WI) and contrast-enhanced T1WI (CE-T1WI) were used to construct a high-risk plaque model with linear support vector classification (linear SVC). The radiological and radiomics features were combined to build a combined model. Receiver operating characteristic (ROC) curves were used to evaluate these models.

RESULTS

Plaque length, burden, and enhancement were independently associated with clinical symptoms and were included in the conventional model, which had an AUC of 0.853 vs. 0.837 in the training and test sets. While the radiomics and the combined model showed an improved AUC: 0.923 vs. 0.925 for the training sets and 0.906 vs. 0.903 in the test sets. Both the radiomics model (p = 0.024, p = 0.018) and combined model (p = 0.042, p = 0.049) outperformed the conventional model in the two sets, whereas the performance of the combined model was not significantly different from that of the radiomics model in the two sets (p = 0.583 and p = 0.606).

CONCLUSION

The radiomics model based on 3D HRMRI can accurately differentiate symptomatic from asymptomatic intracranial arterial plaques and significantly outperforms the conventional model.

Follow-up assessment of atherosclerotic plaques in acute ischemic stroke patients using high-resolution vessel wall MR imaging

PURPOSE

Data on evolution of intracranial plaques in acute ischemic stroke patients after receiving medical therapy is still limited. We aimed to investigate the plaque features associated with culprit lesions and to explore the plaque longitudinal changes during treatment using high-resolution vessel wall MR imaging (VW-MRI).

METHODS

Twenty-three patients (16 men; mean age, 51.4 years ± 11.1) with acute ischemic stroke underwent 3-T VW-MRI for intracranial atherosclerosis and were taken follow-up assessments. Each identified plaque was retrospectively classified as culprit, probably culprit, or nonculprit. Plaque features were analyzed at both baseline and follow-up and were compared using paired t-test, paired Wilcoxon test, or McNemar's test.

RESULTS

A total of 87 intracranial plaques were identified (23 [26.4%] culprit, 10 [11.5%] probably culprit, and 54 [62.1%] nonculprit plaques). The median time interval between initial and follow-up MRI scans was 8.0 months. In the multiple ordinal logistic regression analysis, plaque contrast ratio (CR) (OR, 1.037; 95% CI, 1.013-1.062; P = 0.002) and surface irregularity (OR, 4.768; 95% CI, 1.064-21.349; P = 0.041) were independently associated with culprit plaques. During follow-up, plaque length, maximum thickness, normalized wall index (NWI), stenosis degree, and CR significantly decreased (all P-values < 0.05) in the culprit plaque group. The plaque NWI and CR dropped in the probably culprit plaques (P = 0.041, 0.026, respectively). In the nonculprit plaque group, only plaque NWI and stenosis degree showed significant decrement (P = 0.017, 0.037, respectively).

CONCLUSION

Follow-up VW-MRI may contribute to plaque risk stratification and may provide valuable insights into the evolution of different plaques in vivo.

Prevalence, prognosis, and treatment of atherosclerotic intracranial stenosis in Caucasians

BACKGROUND

Intracranial atherosclerotic stenosis is a highly prevalent cause of stroke worldwide with important ethnic disparities. Widely considered to be a common cause of stroke in Asian and Afro-Caribbean populations, relatively less is known about the burden and significance of intracranial atherosclerotic stenosis in Caucasians.

AIMS

We aim to highlight recent insights and advances into the prevalence, prognosis, and treatment of symptomatic and asymptomatic atherosclerotic intracranial atherosclerotic stenosis in Caucasian patients.

SUMMARY OF REVIEW

We identified 48 articles studying intracranial atherosclerotic stenosis in Caucasian patients with ischemic stroke or transient ischemic attack. Most studies were on hospital-based cohorts of consecutive patients and half were graded as "fair" quality. There was significant variation between studies in the definition of intracranial atherosclerotic stenosis and in the imaging modalities used to detect intracranial atherosclerotic stenosis. Overall, 12.1% of Caucasian patients were found to have any intracranial atherosclerotic stenosis, 6.4% symptomatic intracranial atherosclerotic stenosis and 11.1% asymptomatic intracranial atherosclerotic stenosis, with higher rates at older ages. In studies reporting prognosis, there were 61 and 10 same-territory ischemic strokes in 1000 person-years in patients with symptomatic and asymptomatic intracranial atherosclerotic stenosis, respectively. Percutaneous stenting and angioplasty have not proven superior to intensive medical management in patients with symptomatic intracranial atherosclerotic stenosis.

CONCLUSIONS

Intracranial atherosclerotic stenosis has previously been neglected as a cause of stroke in Caucasians but is highly prevalent at older ages and frequently discovered with the growing use of noninvasive angiography. Intensive medical therapy is the treatment of choice, but there is a need to develop novel treatments or therapeutic approaches to lower the risk of stroke in higher risk patients.

High-Resolution Magnetic Resonance Vessel Wall Imaging for the Evaluation of Intracranial Vascular Pathology

Intracranial vessel wall imaging (IVWI) is an advanced MR imaging technique that allows for direct visualization of the walls of intracranial blood vessels and detection of subtle pathologic vessel wall changes before they become apparent on conventional luminal imaging. When performed correctly, IVWI can increase diagnostic confidence, aid in the differentiation of intracranial vasculopathies, and assist in patient risk stratification and prognostication. This review covers the essential technical underpinnings of IVWI and presents emerging clinical research highlighting its utility for the evaluation of multiple intracranial vascular pathologies.

Prognosis of Asymptomatic Intracranial Stenosis in Patients With Transient Ischemic Attack and Minor Stroke

Importance

Asymptomatic intracranial stenosis (ICS) is a frequent finding on imaging results, particularly in the assessment of acute stroke. Although the management of symptomatic ICS is informed by randomized trials, to our knowledge there are few data on the prevalence and prognosis of asymptomatic ICS in patients with stroke and transient ischemic attack (TIA).

Objective

To study the age-specific prevalence and prognosis of asymptomatic ICS in a population-based cohort of patients with TIA and minor stroke.

Design, Setting, and Participants

All patients (predominantly white) recruited to the Oxford Vascular Study (Oxfordshire, England) between March 1, 2011, and March 1, 2018, with TIA and minor ischemic stroke (National Institutes of Health Stroke Scale score, ≤3), irrespective of age, were included (n = 1579). We determined the age-specific prevalence of 50% or more asymptomatic ICS and the associated stroke risk by face-to-face follow-up to 2018 on standard medical treatment without stenting.

Exposures

Patients underwent magnetic resonance angiography of the intracranial and cervicocranial arteries, computed tomography angiography if magnetic resonance angiography was contraindicated, or carotid/transcranial Doppler ultrasonography if computed tomography angiography was contraindicated.

Main Outcomes and Measures

The primary outcomes were the prevalence and prognosis of asymptomatic ICS.

Results

Of 1368 eligible patients (mean [SD] age, 69.2 [13.9] years; 700 men [51.2%]) with intracranial vascular imaging, 426 ICS were identified in 260 patients (19.0%): 58 (4.2%) with only symptomatic ICS, 155 (11.3%) with only asymptomatic ICS, and 47 (3.4%) with both. The prevalence of any asymptomatic ICS increased from 4.8% for patients younger than 70 years to 34.6% for patients 90 years or older (P for trend < .001; odds ratio per decade, 1.96; 95% CI, 1.69-2.27) and was greater than that of 50% or more asymptomatic carotid bifurcation stenosis (202 [14.8%] vs 105 patients [7.2%]; relative risk, 2.04; 95% CI, 1.63-2.55, P < .001). However, the 155 patients with only asymptomatic ICS had no increase in risk of ischemic stroke compared with those with no ICS (unadjusted HR, 1.03, 95% CI, 0.49-2.17), with 8 first recurrent events (5.2%) during 506 patient-years of follow-up and 3 in the territory of the ICS (annualized risk, 0.59%; 95% CI, 0.12-1.73).

Conclusions and Relevance

The prevalence of asymptomatic ICS increases with age in white patients with TIA and minor stroke and is greater than that of asymptomatic carotid stenosis, but asymptomatic ICS does not increase the short- or medium-term risk of distal recurrent ischemic stroke for patients receiving standard medical treatment.

Kongcun Town Asymptomatic Intracranial Artery Stenosis study in Shandong, China: cohort profile

PURPOSE

The population-based Kongcun Town Asymptomatic Intracranial Artery Stenosis (KT-aICAS) study aims to investigate the prevalence of aICAS and major cardiovascular risk factors (CRFs) or biomarkers related to the development and prognosis of aICAS.

PARTICIPANTS

The KT-aICAS study included 2311 rural residents who were aged ≥40 years and living in Kongcun Town, Shandong Province, China. Baseline examination was conducted from October 2017 to October 2018, during which information on demographics, socioeconomics, personal and family medical history, and lifestyle factors was collected through face-to-face interviews, physical examination and blood tests. aICAS was initially screened using transcranial Doppler examination and then diagnosed using magnetic resonance angiography. Atherosclerosis in carotid arteries was diagnosed via carotid ultrasonography. High-resolution MRI was further used to evaluate the vessel wall of aICAS. Neuropsychological assessments were performed in the participants diagnosed with aICAS and the age-matched and sex-matched controls.

FINDINGS TO DATE

Of the 2311 participants, 2027 (87.7%) completed the diagnostic procedure and aICAS was detected in 154 persons, resulting in an overall prevalence of 7.6%. The prevalence of aICAS increased with advancing age from 5.1% in participants aged 40-49 years to 12.7% in those aged ≥70 years (p<0.001). aICAS was detected in 305 intracranial arteries, including 221 (72.5%) in the anterior circulation and 84 (27.5%) in the posterior circulation (p<0.001). In addition, major CRFs were highly prevalent among middle-aged and elderly rural dwellers who were free of clinical stroke.

FUTURE PLANS

Follow-up examinations will be performed every 3 years following the baseline examination. This study will increase our knowledge about the natural history of aICAS and facilitate studies of aICAS-associated disorders among rural-dwelling Chinese adults, such as ischaemic stroke and vascular cognitive impairment.

TRIAL REGISTRATION NUMBER

ChiCTR1800017197.

Intracranial Atherosclerotic Stenoses: Pathophysiology, Epidemiology, Risk Factors and Current Therapy Options

Intracranial atherosclerotic stenoses (ICAS) are one of the most common causes of first and recurrent cerebrovascular ischaemic events worldwide, with highest prevalence in Asian, Hispanic and African populations. Clinical trials have improved the understanding of epidemiology, risk factors and imaging characteristics of patients with ICAS. Current therapeutic approaches concerning these patients include management of risk factors, best medical therapy, potentially endovascular and rarely surgical therapy. In our review, we elucidate the current epidemiology and evidence in evaluation of risk factors and therapeutic options for providing favourable outcome for patients with ICAS.

Design of stroke imaging package study of intracranial atherosclerosis: a multicenter, prospective, cohort study

Background

Intracranial atherosclerosis (ICAS) is a major cause of stroke worldwide. However, much remains unknown regarding its underlying pathophysiology. High-resolution magnetic resonance imaging (HR-MRI) can clearly display intracranial vessel wall lesions in vivo. The aim of stroke imaging package study of ICAS (SIPS-ICAS) study is to explore the stroke mechanisms of symptomatic ICAS, the dynamic changes under aggressive medical treatment and their associations with clinical events using conventional MRI sequences plus HR-MRI.

Methods

This is a multicenter, prospective, cohort study recruiting first-ever acute ischemic stroke patients attributed to intracranial large artery stenosis (>50% or occlusion). Subjects undergo a pre-designed stroke imaging packages at baseline and are recommended to receive aggressive medical treatments. Participants will be followed up for functional outcome, stroke recurrence, and death events at 3, 6 and 12 months and retake HR-MRI imaging at 6 months.

Results

Enrollment began in November 2018 and 96 patients have been enrolled as of September 2019.

Conclusions

The SIPS-ICAS study will provide insights into the pathophysiology of ICAS and identify specific imaging markers for risk stratification and prognosis prediction. At the same time, the feasibility and validity of the new stroke imaging package including HR-MRI will be assessed, which is promising for clinical routine use.

Prevalence of Systemic Atherosclerosis Burdens and Overlapping Stroke Etiologies and Their Associations With Long-term Vascular Prognosis in Stroke With Intracranial Atherosclerotic Disease

Importance

Patients who have experienced stroke with intracranial atherosclerotic disease (ICAD) may also have concomitant atherosclerosis in different arterial beds and other possible causes for ischemic stroke. However, little is known about the frequency and prognostic effect of such overlapping diseases.

Objectives

To describe the prevalence of systemic atherosclerotic burdens and overlapping stroke etiologies and their contributions to long-term prognoses among patients who have experienced stroke with ICAD.

Design, Setting, and Participants

The Asymptomatic Myocardial Ischemia in Stroke and Atherosclerotic Disease study is a single-center prospective study in which 405 patients with acute ischemic stroke within 10 days of onset were consecutively enrolled between June 2005 and December 2008 and followed up for 4 years. After excluding 2 patients because of incomplete investigations, 403 were included in this analysis.

Main Outcomes and Measures

Significant ICAD was defined as having 50% or greater stenosis/occlusion by contrast-enhanced/time-of-flight magnetic resonance angiography, computed tomography angiography, and/or transcranial Doppler ultrasonography. Systemic vascular investigations on atherosclerotic disease were performed with ultrasonography in carotid arteries, aorta and femoral arteries, and by angiography in coronary arteries. Coexistent stroke etiologies were assessed using the atherosclerosis, small-vessel disease, cardiac pathology, other cause, and dissection (ASCOD) grading system. We estimated the 4-year risk of major adverse cardiovascular events (MACE), including vascular death, nonfatal cardiac events, nonfatal stroke, and major peripheral arterial events.

Results

Of 403 participants, 298 (74%) were men and the mean (SD) age was 62.6 (13.1) years. Significant ICAD was found in 146 (36.2%). Patients with significant ICAD more often had aortic arch (70 [60.9%] vs 99 [49.0%]; P = .04) and coronary artery (103 [76.9%] vs 153 [63.2%]; P = .007) atherosclerosis than those without. Among patients with ICAD, concurrent stenosis in the extracranial carotid artery (24 [23.4%] vs 3 [9.0%]; P = .08; adjusted hazard ratio[aHR] = 2.12) and the coronary artery (19 [29.9%] vs 8 [12.8%]; P = .01; aHR = 1.90) increased the MACE risk. Furthermore, patients with ICAD who also had any cardiac pathology (ASCOD grade C1-3) were at a higher MACE risk than others (grade C0) (20 [28.2%] vs 7 [11.4%]; P = .01; aHR = 2.24). By contrast, patients with ICAD with any form of small vessel disease (grade S1-3) had a lower MACE risk than those without (grade S0) (20 [17.3%] vs 6 [34.6%]; P = .05; aHR = 0.23).

Conclusions and Relevance

Patients with ICAD often have coexisting systemic atherosclerosis and multiple potential stroke mechanisms that affect their prognosis, suggesting that extensive evaluations of overlapping diseases may allow better risk stratification.

Risk factors outperform intracranial large artery stenosis predicting unfavorable outcomes in patients with stroke

Background

This study examined how intracranial large artery stenosis (ILAS), symptomatic and asymptomatic ILAS, and risk factors affect unfavorable outcome events after medical treatment in routine clinical practice.

Methods

This was a 24-month prospective observational study of consecutively recruited stroke patients. All participants underwent magnetic resonance angiography, and their clinical characteristics were assessed. Outcome events were vascular outcome, recurrent stroke, and death. Cox regression analyses were performed to identify potential factors associated with an unfavorable outcome, which included demographic and clinical characteristics, the risk factors, and stenosis status.

Results

The analysis included 686 patients; among them, 371 were assessed as ILAS negative, 231 as symptomatic ILAS, and 84 as asymptomatic ILAS. Body mass index (p < .05), hypertension (p = .01), and old infarction (p = .047) were factors relating to vascular outcomes. Hypertension was the only factor for recurrent stroke (p = .035). Poor glomerular filtration rate (< 30 mL/min/1.73 m²) (p = .011) and baseline National Institutes of Health Stroke Scale scores (p < .001) were significant predictors of death.

Conclusions

This study extended previous results from clinical trials to a community-based cohort study by concurrently looking at the presence/absence of stenosis and a symptomatic/asymptomatic stenotic artery. Substantiated risk factors rather than the stenosis status were predominant determinants of adverse outcome. Although the degree of stenosis is often an indicator for treatment, we suggest risk factors, such as hypertension and renal dysfunction, should be monitored and intensively treated.

Collateral perfusion using arterial spin labeling in symptomatic versus asymptomatic middle cerebral artery stenosis

The purpose was to assess the difference of collaterals in symptomatic versus asymptomatic patients with unilateral middle cerebral artery (MCA) stenosis by comparing cerebral blood flow (CBF) at two post labeling delays (PLD) using three-dimensional pseudo-continuous arterial spin labeling (3D pCASL). Eighty-one patients (49 symptomatic and 32 asymptomatic) with unilateral MCA stenosis ≥50% who underwent pCASL with two PLDs were included. Mean CBF and CBF subtraction images between two PLDs of MCA territories were compared in symptomatic and asymptomatic groups, respectively. Compared with the asymptomatic group, patients with symptomatic MCA stenosis had significantly lower CBF in the MCA territory of stenotic side at each PLD. The CBF of stenotic territory showed greater increase than that of normal side from PLD 1.5 to 2.5 s. The CBF of asymptomatic MCA territory increased similarly with that of symptomatic MCA territory from PLD of 1.5 to 2.5 s in stenotic side, while symptomatic patients experienced significantly slower antegrade flow. On CBF subtraction images, asymptomatic patients showed larger volume of differences between PLD of 1.5 and 2.5 s compared with those of symptomatic patients ( p = 0.037). The results suggest that more robust collateral perfusion on two-delay 3D pCASL is present in asymptomatic patients compared with symptomatic patients.

Middle Cerebral Artery Atherosclerosis and Deep Subcortical Infarction: A 3T Magnetic Resonance Vessel Wall Imaging Study

BACKGROUND

Deep subcortical infarction is a major subtype of stroke in middle cerebral artery (MCA) territory. This study aims to evaluate the relationship between characteristics of MCA plaque and features of deep subcortical infarction.

METHODS

Patients with recent acute ischemic stroke and deep subcortical infarction were prospectively enrolled. Both multicontrast brain sequences and 3D high-resolution vessel wall imaging (VWI) sequences were scanned for all patients. MCA plaque characteristics, including plaque presence, location, maximum vessel wall thickness (Max WT), signal intensity and luminal stenosis, and deep subcortical infarction features, including lowest infarct layer index (LILI), area, volume, maximum area, and infarct quantity were evaluated. Infarct feature differences were compared between MCA plaque+ group and MCA plaque- group. The correlations between MCA plaque characteristics and deep subcortical infarction features were analyzed.

RESULTS

Of all 50 patients included in this study, 30 (60%) had MCA plaques. All deep subcortical infarction was single lesion for patients without MCA plaque. The average number of deep subcortical infarction for patients with MCA plaque was 3.10 ± 4.44. The LILI (P = .036) and infarct quantity (P = .030) showed significant differences between 2 groups. Max WT (P = .025) and stenosis degree (P = .023) were negatively correlated with LILI. Intraplaque hemorrhage was positively correlated with maximum area (P = .029) and infarct volume (P = .030).

CONCLUSIONS

MCA plaque characteristics were correlated with deep subcortical infarct features. Magnetic resonance VWI may provide more information for etiological evidence of deep subcortical infarction.

Concomitant Asymptomatic Intracranial Atherosclerotic Stenosis Increase the 30-Day Risk of Stroke in Patients Undergoing Symptomatic Intracranial Atherosclerotic Stenosis Stenting

BACKGROUND

In the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial, 19.1% of ischemic strokes occurred out of the territory of previously symptomatic stenosis during the mean follow-up period of 23.4 months. However, it is unknown how many ischemic strokes were due to a previously asymptomatic intracranial atherosclerotic stenosis (ICAS). The objective of this study was to investigate whether the concomitant asymptomatic ICAS influences the outcome of patients undergoing symptomatic ICAS stenting.

METHODS

We retrospectively reviewed 576 consecutive patients with nondisabling ischemic stroke (modified Rankin scale score of ≤3) who were treated with symptomatic ICAS (≥70% stenosis) stenting with or without concomitant asymptomatic ICAS. The baseline characteristics and the 30-day primary end points (stroke or death after stenting) were compared by bivariate and multivariable logistic analyses.

RESULTS

The 30-day rate of primary end points was 5.2%, which was higher in patients with concomitant asymptomatic ICAS (≥50% stenosis) than in those without asymptomatic ICAS (no stenosis or <50% stenosis) (8.9% versus 3.8%, P = .014). In patients with concomitant asymptomatic ICAS, 25% of ischemic strokes occurred out of the territory of the stented artery, whereas in patients without asymptomatic ICAS, no ischemic stroke occurred out of the territory of the stented artery. Multivariable analysis showed that concomitant asymptomatic ICAS was an independent risk factor for 30-day stroke (odds ratio = 2.37, 95% confidence interval, 1.14-5.63; P = .023).

CONCLUSIONS

Concomitant asymptomatic ICAS (≥50% stenosis) might increase the 30-day risk of stroke in patients undergoing symptomatic ICAS stenting.

Cerebral Arterial Stenosis in Patients with Spontaneous Intracerebral Hemorrhage

OBJECTIVE

Spontaneous intracerebral hemorrhage (ICH) and ischemic stroke share common vascular risk factors such as aging and hypertension. Previous studies suggested that the rate of recurrent ICH and ischemic stroke might be similar after ICH. Presence of cerebral arterial stenosis is a potential risk factor for future ischemic stroke. This study investigated the prevalence and factors associated with cerebral arterial stenosis in Korean patients with spontaneous ICH.

METHODS

A total of 167 patients with spontaneous ICH were enrolled. Intracranial arterial stenosis (ICAS) and extracranial arterial stenosis (ECAS) were assessed by computed tomography angiography. Presence of ICAS was defined if patients had arterial stenosis in at least one intracranial artery. ECAS was assessed in the extracranial carotid artery. More than 50% luminal stenosis was defined as presence of stenosis. Prevalence and factors associated with presence of ICAS and cerebral arterial stenosis (presence of ICAS and/or ECAS) were investigated by multivariable logistic regression analysis.

RESULTS

Thirty-two (19.2%) patients had ICAS, 7.2% had ECAS, and 39 (23.4%) patients had any cerebral arterial stenosis. Frequency of ICAS and ECAS did not differ among ganglionic ICH, lobar ICH, and brainstem ICH. Age was higher in patients with ICAS (67.6±11.8 vs. 58.9±13.6 years p=0.004) and cerebral arterial stenosis (67.9±11.6 vs. 59.3±13.5 years, p<0.001) compared to those without stenosis. Patients with ICAS were older, more frequently had diabetes, had a higher serum glucose level, and had a lower hemoglobin level than those without ICAS. Patients with cerebral arterial stenosis were older, had diabetes and lower hemoglobin level, which was consistent with findings in patients with ICAS. However, patients with cerebral arterial stenosis showed higher prevalence of hypertension and decreased kidney function compared to those without cerebral arterial stenosis. Multivariable logistic regression analyses showed that aging and presence of diabetes independently predicted the presence of ICAS, and aging, diabetes, and hypertension were independently associated with presence of cerebral arterial stenosis.

CONCLUSION

19.2% of patients with spontaneous ICH had ICAS, but the prevalence of ECAS was relatively lower (7.2%) compared with ICAS. Aging and diabetes were independent factors for the presence of ICAS, whereas aging, hypertension, and diabetes were factors for the cerebral arterial stenosis.

Impact of MCA stenosis on the early outcome in acute ischemic stroke patients

Background

Asians have higher frequency of intracranial arterial stenosis. The present study aimed to compare the clinical features and outcomes of ischemic stroke patients with and without middle cerebral artery (MCA) stenosis, assessed by transcranial sonography (TCS), based on the Taiwan Stroke Registry (TSR).

Methods

Patients with acute ischemic stroke or transient ischemic attack registered in the TSR, and received both carotid duplex and TCS assessment were categorized into those with stenosis (≥50%) and without (<50%) in the extracranial internal carotid artery (ICA) and MCA, respectively. Logistic regression analysis, Kaplan-Meier method and Cox proportional hazard model were applied to assess relevant variables between groups.

Results

Of 6003 patients, 23.3% had MCA stenosis, 10.1% ICA stenosis, and 3.9% both MCA and ICA stenosis. Patients with MCA stenosis had greater initial NIHSS, higher likelihood of stroke-in-evolution, and more severe disability than those without (all p<0.001). Patients with MCA stenosis had higher prevalence of hypertension, diabetes and hypercholesterolemia. Patients with combined MCA and extracranial ICA stenosis had even higher NIHSS, worse functional outcome, higher risk of stroke recurrence or death (hazard ratio, 2.204; 95% confidence intervals, 1.440–3.374; p<0.001) at 3 months after stroke than those without MCA stenosis.

Conclusions

In conclusion, MCA stenosis was more prevalent than extracranial ICA stenosis in ischemic stroke patients in Taiwan. Patients with MCA stenosis, especially combined extracranial ICA stenosis, had more severe neurological deficit and worse outcome.

Prophylactic Dual Catheter Technique to Prevent Side Branch Snowplowing Complications during Angioplasty and Stenting

Objective

Angioplasty and Stenting of intracranial atherosclerotic lesions have a higher complication rate and a large proportion of this is attributable to side branch arterial occlusion from forceful displacement of the atheroma into the ostia or snowplowing effect. This can result in severe disabilities when it result in small infarcts involving eloquent areas in the posterior circulation or the motor tracts.

Materials and Methods

We present a series of 6 cases utilizing a new dual catheter technique for maintaining the patency of at-risk vessels during angioplasty and stenting. There are several methods previously described to help reduce the incidence of stroke but because they do not have a physical presence in the ostia to protect it, they are unable to guarantee the patency of the vessel.

Results

All 6 patients underwent angioplasty and stenting with the technique. The patients were assessed for complications with post-procedure magnetic resonance imaging and no complications were found.

Conclusion

In this preliminary series, the dual catheter technique appears to safe and effective in preventing occlusion of the adjacent branch arteries. This technique may facilitate the use of the Wingspan stent in the treatment of intracranial atherosclerotic stenotic segments by reducing the risk of peri-procedural stroke.

A Prospective Study of Asymptomatic Intracranial Atherosclerotic Stenosis in Neurologically Normal Volunteers in a Japanese Cohort

Atherosclerotic stenosis of major intracranial arteries is a leading cause of ischemic stroke in Asia. However, the long-term prognosis of asymptomatic intracranial atherosclerotic stenosis (ICAS) in healthy volunteers has not been fully examined. Here, we conducted a longitudinal study to examine the prognosis of healthy volunteers with asymptomatic ICAS and to determine the risk factors for ICAS, including asymptomatic brain parenchymal lesions. We studied 2,807 healthy Japanese volunteers with no history of stroke (mean age, 62.0 years). They were followed for a mean interval of 64.5 months. The degree of ICAS and the presence of asymptomatic brain lesions were assessed by using magnetic resonance imaging. Asymptomatic ICAS was detected in 166 volunteers (5.9%) at the initial examination. Moderate and mild stenoses were observed in 1.5 and 4.4% of patients, respectively. Significant risk factors for ICAS were older age and a history of hypertension and/or dyslipidemia. During follow-up, ischemic stroke developed in 32 volunteers. Seven strokes occurred in the ICAS group, whose stroke incidence rate was higher than that in the non-ICAS group (0.78 vs. 0.18% per year). According to a Cox regression analysis, asymptomatic ICAS was an independent risk factor for future ischemic stroke after adjustment for age. Furthermore, after asymptomatic brain lesions were taken into account, ICAS was still a significant risk factor for stroke onset. In conclusion, even mild to moderate asymptomatic ICAS was a significant risk factor for future stroke, independent of asymptomatic brain lesions, in a healthy Japanese population. Mild to moderate ICAS might be a therapeutic target for stroke prevention.

Different blood pressure indexes on intracranial arterial stenosis in Asymptomatic Polyvascular Abnormalities in Community study in China

BACKGROUND

The association between hypertension and cerebrovascular events is shown in some large-scale studies, but it remains unclear which blood pressure index is the most sensitive risk factor for cerebrovascular stenosis.

METHODS

We investigated the potential associations between different blood pressure indexes and intracranial arterial stenosis (ICAS) in the study. The population-based Asymptomatic Polyvascular Abnormalities in Community study examined asymptomatic intracranial arterial abnormalities in a Chinese population and included participants aged more than 40 years without a history of stroke, transient ischemic attack, and coronary heart disease. ICAS was diagnosed by transcranial Doppler sonography. Blood pressure was measured with a mercury manometer three times; an average result of SBP and DBP was used, and mean arterial pressure (MAP) and pulse pressure (PP) were calculated for the statistical analysis.

RESULTS

Out of the 4422 study participants, 711 (16.1%) showed an asymptomatic ICAS. After adjusting for age, waist circumference, drinking, diabetes, dyslipidemia, and blood concentration of uric acid, C-reactive protein, and homocysteine, ICAS was significantly associated with a higher SBP [from decile 6, odds ratio (OR) 3.093; 95% confidence interval (CI) 1.909, 5.012; P < 0.01), a higher MAP (from decile 7, OR 2.889; 95% CI 1.853, 4.504; P < 0.01), and a higher PP (from decile 5, OR 2.295;95% CI 1.463, 3.601; P < 0.01). Using a receiver-operating characteristic curve to estimate the predictive value of different blood pressure indexes for ICAS, SBP, MAP, and PP, were predictive indexes for ICAS and PP showed the largest predictive value (area under the curve = 0.737).

CONCLUSIONS

The current study results suggest that SBP, MAP, and PP are all associated with asymptomatic ICAS. PP may be the most sensitive index to predict ICAS.

Characterization of intracranial atherosclerotic stenosis using high-resolution MRI study--rationale and design

BACKGROUND

Intracranial atherosclerosis is a leading cause of stroke, but little is known about the composition of the intracranial atherosclerotic lesion and how intracranial plaque morphology is related to the risk of stroke. High-resolution magnetic resonance imaging (HR MRI) has been used in patients with extracranial carotid atherosclerosis as an in vivo tool to identify, with high-interrater agreement, histologically defined plaque components (i.e., intraplaque hemorrhage, fibrous cap, and lipid core), which have been shown to be predictors of recurrent stroke. With careful imaging the components of atherosclerotic plaque can be visualized in the intracranial arteries using HR MRI, but there are no reports of reproducibility or interrater reliability.

METHODS/STUDY DESIGN

The Characterization of intracranial atherosclerotic stenosis using high-resolution MRI (CHIASM) study is a single-center NIH-funded prospective observational study, to (1) demonstrate high -interrater agreement for identifying intracranial plaque components on HR MRI, (2) determine the frequency of these components in symptomatic versus asymptomatic plaques, and (3) estimate the 1-year rate of stroke in the territory of high-risk plaque components. CHIASM will recruit 90 patients with 50-99% intracranial atherosclerosis to undergo HRMRI of the intracranial artery plaque at enrollment and 1-year follow-up. Both symptomatic and asymptomatic subjects will be recruited.

CONCLUSION

Determination of good interrater reliability is an important first step in the development of HR MRI as a tool to predict risk in patients with intracranial atherosclerosis. This study will inform the design of future multicenter studies to determine the prevalence and prognosis of intracranial atherosclerotic plaque components. Such studies could lead to new understanding of the pathophysiological mechanisms of cerebral ischemia in patients with atherosclerotic intracranial stenosis, improvements in risk stratification, and potentially to new treatments of this common and serious disease.

Multiple intracranial arterial stenosis influences the long-term prognosis of symptomatic middle cerebral artery occlusion

Background

Large intracranial occlusive vascular disease is a major contributor to the incidence of stroke worldwide, especially when it involves the middle cerebral artery (MCA). The data on the prognosis of symptomatic atherosclerotic MCA occlusions (MCAO) with concomitant intracranial arterial disease (MCAO-AIS) are limited. MCAO-AIS may reflect the extent of the atherosclerotic intracranial disease, we hypotheses that coexisting intracranial arterial disease influenced the prognosis of MCAO.

Methods

Patients having survived at least one month after the initial ischemic stroke who suffered from atherosclerotic occlusion of the MCA were enrolled. According to their concomitant atherosclerotic intracranial arterial disease, the patients were assigned to one of two groups: the MCAO or the MCAO-AIS. All of the patients’ cerebrovascular risk factors were recorded. Recurrent ischemic stroke and death were the end-point events during the follow-up.

Results

A total of 232 patients (mean age 57.68 ± 9.50 years; 69% male) were analyzed. The mean follow-up time was 17.65 months. The end-point events occurred in 35 (15.09%) patients, resulting in an annual rate of 10.26%. The presence of MCAO- AIS was an independent risk factor associated with the patient’s prognosis in the cohort (OR = 3.426, 95% CI 1.261 to 9.308; p = 0.016), as well as gender and diabetes mellitus. The MCAO-AIS were more likely to experience ipsilateral ischemic strokes, but the difference was not statistically significant.

Conclusion

Concomitant intracranial arterial disease may influence the prognosis of patients with atherosclerotic MCAO. The result warrants further research in larger sample population.

Long-term natural history of intracranial arterial stenosis: an MRA follow-up study

BACKGROUND

Intracranial arterial stenosis (ICAS) is a major cause of ischemic stroke in Asians. Despite the clinical importance of ICAS, the literature on the natural history of ICAS has been less enlightening. The aims of our study were to evaluate a long-term natural course of symptomatic and asymptomatic ICAS.

METHODS

102 subjects (37 symptomatic and 65 asymptomatic) underwent follow-up MR angiography (MRA) with a median time interval between initial and follow-up MRA of 5.7 years (range 3.6-8.5 years). For each patient, the extent of stenosis of five arteries (both middle cerebral arteries, both intracranial internal carotid arteries, and basilar artery) was classified according to five grades, by consensus: normal, mild (signal reduction <50%), moderate (signal reduction ≥50%), severe (focal signal loss with the presence of a distal signal), and occlusion. Because the sample size was too small to adjust for multiple confounders, we applied the propensity score.

RESULTS

Mean (Standard deviation) age at initial MRA was 63.5 (9.6) and 54% were men. The progression rate of ICAS differed significantly between symptomatic and asymptomatic patients (22 vs. 8%, p < 0.01), indicating a 3-fold risk of progression for symptomatic stenosis compared with asymptomatic stenosis [odds ratio (OR) 3.27, 95% confidence interval (CI) 1.08-9.95]. After adjustment for propensity score, the OR was 4.84 (95% CI, 1.40-16.7). In the matched cohort, the relative risk of stenosis progression was 5.20 for symptomatic stenosis (95% CI 1.00-27.23) compared with asymptomatic stenosis.

CONCLUSION

We found a greater risk of progression for symptomatic stenosis compared with asymptomatic stenosis.

Solving the Issue of Restenosis After Stenting of Intracranial Stenoses: Experience with Two Thin-Strut Drug-Eluting Stents (DES)-Taxus Element™ and Resolute Integrity™

PURPOSE

Thin-strut, flexible DES are suitable for intracranial stenting and may improve long-term vessel patency. The purpose of this study was to report our experience with two new-generation DES for the treatment of intracranial atherosclerotic disease.

PATIENTS AND METHODS

We retrospectively reviewed all patients treated with Taxus Element™ or Resolute Integrity™ stent for an intracranial atherosclerotic stenosis between March 2011 and August 2013. Technical success was defined as the ability to deploy the device at the desired location and reduce the degree of stenosis below 50 %. All procedure-related strokes were recorded. Control angiography was scheduled after 6 weeks, 3, 6, and 12 months and yearly thereafter. A luminal narrowing ≥50 % was regarded as a restenosis. Stroke recurrence in the territory of the treated artery was reported.

RESULTS

In the defined period we treated 101 patients harboring 117 intracranial stenoses. The procedure was successful in 100 (85.5 %) lesions. Procedure-related strokes occurred in 10 (9.9 %) patients with a permanent morbidity in 3 (3.0 %). Follow-up angiography was available for 83 of 100 (83.0 %) successfully treated lesions with an average of 355 days (IQR 153-482 days). Three (3.6 %) asymptomatic restenoses were detected. All occurred after treatment with Resolute Integrity™, none after Taxus Element™ (p = 0.059). New strokes in the territory of the treated artery were encountered in 2 (2.6 %) occasions.

CONCLUSION

Thin-strut DES improve long-term patency and reduce the risk of subsequent stroke. Differences between devices may exist. Feasibility is comparable to bare-metal balloon-mounted stents and procedure-related strokes occurred within the expected range.

Recurrence in intracranial atherosclerotic disease: a stenosis-based analysis

BACKGROUND

Intracranial atherosclerotic disease is a common cause of stroke; its incidence and prevalence vary widely by ethnicity. The aim of our study was to analyze the recurrence rate of cerebrovascular events in patients with symptomatic and asymptomatic intracranial stenosis (IS).

METHODS

We conducted a historical cohort study including all patients admitted in our hospital for stroke or transient ischemic attack (TIA) during 2011 and 2012 with information on intracranial circulation (ultrasonography and/or computed tomography angiography). We identified patients with symptomatic and asymptomatic IS and studied the recurrence of cerebrovascular events (TIA or ischemic stroke within the territory of the stenosis) for a minimum follow-up period of 6 months after the diagnosis of IS. For the recurrence rate estimation, patients with other potentially embolic diseases (in cervical arteries or heart) were excluded. We calculated the rate of recurrence of cerebrovascular events and performed Kaplan-Meier survival curves for symptomatic and asymptomatic IS.

RESULTS

We investigated 1302 patients, mean age was 72.41 years (standard deviation 12.75). We identified 218 IS in 158 patients, 77 were symptomatic and 141 were asymptomatic. The recurrence rate of cerebrovascular events was 12.32 per 100 patient-years, with a mean time to recurrence of 1.73 months for symptomatic intracranial stenosis (SIS) and .88 per 100 patient-years for asymptomatic IS (P < .001).

CONCLUSIONS

These results indicate a high risk of early recurrence of stroke in the territory of a SIS, highlighting the importance of its early diagnosis and aggressive treatment.

Intracranial atherosclerosis

Atherosclerotic disease often involves the intracranial arteries including those encased by cranial bones and dura, and those located in the subarachnoid space. Age, hypertension, and diabetes mellitus are independent risk factors for intracranial atherosclerosis. Intracranial atherosclerosis can result in thromboembolism with or without hypoperfusion leading to transient or permanent cerebral ischaemic events. High rates of recurrent ischaemic stroke and other cardiovascular events mandate early diagnosis and treatment. Present treatment is based on a combination of antiplatelet drugs, optimisation of blood pressure and LDL cholesterol values, and intracranial angioplasty or stent placement, or both, in selected patients.

Intracranial plaque enhancement in patients with cerebrovascular events on high-spatial-resolution MR images

PURPOSE

To characterize intracranial plaque inflammation in vivo by using three-dimensional (3D) high-spatial-resolution contrast material-enhanced black-blood (BB) magnetic resonance (MR) imaging and to investigate the relationship between intracranial plaque inflammation and cerebrovascular ischemic events.

MATERIALS AND METHODS

The study was approved by the institutional review board and was HIPAA compliant. Twenty-seven patients (19 men; mean age, 56.8 years ± 12.4 [standard deviation]) with cerebrovascular ischemic events (acute stroke, n = 20; subacute stroke, n = 2; chronic stroke, n = 3; transient ischemic attack, n = 2) underwent 3D time-of-flight MR angiography and contrast-enhanced BB 3-T MR imaging for intracranial atherosclerotic disease. Each identified plaque was classified as either culprit (the only or most stenotic lesion upstream from a stroke), probably culprit (not the most stenotic lesion upstream from a stroke), or nonculprit (not within the vascular territory of a stroke). Plaque contrast enhancement was categorized on BB MR images (grade 0, enhancement less than or equal to that of normal arterial walls seen elsewhere; grade 1, enhancement greater than grade 0 but less than that of the pituitary infundibulum; grade 2, enhancement greater than or equal to that of the pituitary infundibulum), and degree of contrast enhancement was calculated. Associations of the likelihood of being a culprit lesion with both plaque contrast enhancement and plaque thickness were estimated with ordinal logistic regression.

RESULTS

Seventy-eight plaques were identified in 20 patients with acute stroke (21 [27%] culprit, 12 [15%] probably culprit, and 45 [58%] nonculprit plaques). In these patients, grade 2 contrast enhancement was associated with culprit plaques (odds ratio 34.6; 95% confidence interval: 4.5, 266.5 compared with grade 0) when adjusted for plaque thickness. Grade 0 was observed in only nonculprit plaques. Culprit plaques had a higher degree of contrast enhancement than did nonculprit plaques (25.9% ± 13.4 vs 13.6% ± 12.3, P = .003).

CONCLUSION

Contrast enhancement of intracranial atherosclerotic plaque is associated with its likelihood to have caused a recent ischemic event and may serve as a marker of its stability, thereby providing important insight into stroke risk.

Role of stenting for intracranial atherosclerosis in the post-SAMMPRIS era

Introduction. The initial promise of endovascular stenting for the treatment of intracranial atherosclerotic disease (ICAD) has been tempered by the results of the SAMMPRIS trial which demonstrated better outcomes with medical management compared to stenting for symptomatic ICAD. We review post-SAMMPRIS ICAD stenting outcomes. Methods. A comprehensive literature search was performed using PubMed to identify all ICAD stenting series published after the SAMMPRIS in September 2011. The type and design of the stent, number of patients and lesions, inclusion criteria, and clinical and angiographic outcomes were noted. Results. From October 2011 to August 2013, 19 ICAD stenting series were identified describing the interventional outcomes for 2,196 patients with 2,314 lesions. Of the 38 different stents used, 87% were balloon-expandable stents (BESs) and 13% were self-expanding stents. The median minimum stenosis was 50%. The median rates of technical success rate, postprocedural ischemic events, and symptomatic in-stent restenosis (ISR) were 98% (range 87–100%), 9.4% (range 0–25%), and 2.7% (range 0–11.1%), respectively. The median follow-up durations were one to 67 months. Conclusions. The management of severe ICAD remains controversial. Future trials are needed to define the optimal patient, lesion, and stent characteristics which will portend the best outcomes with intervention.

A non-invasive technique for visualization of microvessels in asymptomatic patients with middle cerebral artery steno-occlusion

We determined whether 7T magnetic resonance angiography (MRA) could be used for clearly observing microvessels in a clinically asymptomatic patient with steno-occlusion of the middle cerebral artery (MCA). We utilized 3T magnetic resonance imaging to obtain the brain images of a clinically asymptomatic patient and noted MCA steno-occlusion. In comparison with 3T MRA, 7T MRA could clearly delineate the microvessels, including lenticulostriate arteries and presumed collaterals, and our observation was comparable to that with conventional digital subtraction angiography. We report an interesting case of a clinically asymptomatic patient with MCA steno-occlusion.

[Recent studies on intracranial stenosis]

CLINICAL ISSUE

Symptomatic intracranial stenoses are associated with a high risk of stroke. Medical management with platelet inhibitors or anticoagulation has not been shown to substantially lower this risk. Hence, alternative treatment options are desperately needed.

TREATMENT INNOVATIONS

The concept of percutaneous intervention using balloon angioplasty with or without stenting is appealing at first sight which is why intracranial balloons and stents were developed.

PERFORMANCE

Initial studies using dedicated intracranial stents were more promising; however, the only randomized trial recently published using a dedicated intracranial self-expanding stent demonstrated a high periprocedural complication rate. EVALUATION AND PRACTICAL RECOMMENDATIONS: Due to study design limitations it would be premature to categorically denounce an interventional option for the treatment of symptomatic intracranial stenoses. More importantly, the results of the randomized SAMMPRIS trial should stimulate the development of safer technology and patient selection to minimize procedural risks. This will perhaps allow significant risk reduction of this potentially devastating intracranial condition when it cannot otherwise be addressed.

Chronic hemodynamic compromise and cerebral ischemic events in asymptomatic or remote symptomatic large-artery intracranial occlusive disease

BACKGROUND AND PURPOSE

In asymptomatic or remote symptomatic LAICOD, the risk of ischemic events is low in general, but there may be a subgroup of higher risk patients who require aggressive medical management. The purpose of this study was to determine whether chronic hemodynamic compromise is a predictor of ischemic events in asymptomatic or remote symptomatic LAICOD.

MATERIALS AND METHODS

We prospectively studied 51 asymptomatic, 19 coexistent asymptomatic, and 19 remote (>6 months) symptomatic patients with atherosclerotic intracranial internal carotid artery or middle cerebral artery disease by using (15)O-PET. MP was defined as decreased CBF, increased OEF, and a decreased CBF/CBV ratio. All patients were followed up for 2 years or until occurrence of stroke or TIA or death.

RESULTS

Bypass surgery was performed in 4 patients (2 with MP). Three cerebral ischemic events (1 TIA in an asymptomatic patient, 1 stroke, and 1 TIA in a remote symptomatic patient) occurred in the vascular territory ipsilateral to LAICOD. Kaplan-Meier analysis with censoring at the time of bypass surgery revealed that the incidence of ipsilateral ischemic events in patients with MP (2/5) was significantly higher than that in patients without MP (1/84) (log-rank test; P < .0001). The relative risk conferred by MP was 83.1 (95% confidence interval, 6.8-1017.4; P < .001). The incidence of ipsilateral ischemic events in patients with decreased CBF/CBV (2/9) was also significantly higher than that of patients without it (1/80) (P = .0001).

CONCLUSIONS

Chronic hemodynamic compromise may be a predictor of ischemic events in both asymptomatic and remote symptomatic LAICOD.

Stroke radiology and distinguishing characteristics of intracranial atherosclerotic disease in native South Asian Pakistanis

BACKGROUND

There are no descriptions of stroke mechanisms from intracranial atherosclerotic disease in native South Asian Pakistanis.

METHODS

Men and women aged ≥ 18 years with acute stroke presenting to four tertiary care hospitals in Karachi, Pakistan were screened using magnetic resonance angiography/transcranial Doppler scans. Trial of ORG 10172 in Acute Stroke Treatment criteria were applied to identify strokes from intracranial atherosclerotic disease.

RESULTS

We studied 245 patients with acute stroke due to intracranial atherosclerotic disease. Two hundred thirty scans were reviewed. Also, 206/230 (89.0%) showed acute ischaemia. The most frequent presentation was with cortically based strokes in 42.2% (87/206) followed by border-zone infarcts (52/206, 25.2%). Increasing degrees of stenosis correlated with the development of both cortical and border-zone strokes (P = 0.002). Important associated findings were frequent atrophy (166/230, 72.2%), silent brain infarcts (66/230, 28%) and a marked lack of severe leukoaraiosis identified in only 68/230 (29.6%). A total of 1870 arteries were studied individually. Middle cerebral artery was the symptomatic stroke vessel in half, presenting with complete occlusion in 66%. Evidence of biological disease, symptomatic or asymptomatic was identified in 753 (40.2%) vessels of which 543 (72%) were significantly (>50%) stenosed at presentation.

CONCLUSION

Intracranial atherosclerotic disease is a diffuse process in Pakistani south Asians, with involvement of multiple vessels in addition to the symptomatic vessel. The middle cerebral artery is the most frequent symptomatic vessel presenting with cortical embolic infarcts. There is a relative lack of leukoaraiosis. Concomitant atrophy, silent brain infarcts and recent ischaemia in the symptomatic territory are all frequently associated findings.

Risk factors and outcome of patients with symptomatic intracranial stenosis presenting with lacunar stroke

BACKGROUND AND PURPOSE

We hypothesized that patients with intracranial stenosis with lacunar stroke presentations would face lower risks of recurrent stroke than those with index nonlacunar strokes, and that their recurrent strokes would predominantly be lacunar.

METHODS

We analyzed subjects enrolled with an index stroke into the Warfarin Aspirin Symptomatic Intracranial Disease (WASID) trial. The index stroke was classified as lacunar or nonlacunar. The primary end point was recurrent ischemic stroke. Cox proportional hazard models were generated with stratification for severity of stenosis.

RESULTS

Three hundred forty-seven subjects were enrolled after an index stroke; 38 were lacunar and 309 were nonlacunar. Over a mean follow-up of 1.8 years, there was no significant difference in stroke recurrence between patients whose index stroke was lacunar (7 of 38 [18%]) versus nonlacunar (69 of 309 [22%]; hazard ratio, 0.79; 95% CI, 0.36-1.71). Furthermore, no significant differences were found when groups were stratified by 50% to 69% stenosis (hazard ratio, 0.50; 95% CI, 0.12-2.1) and ≥ 70% stenosis (hazard ratio, 0.87; 95% CI, 0.34-2.2). Of the 7 recurrent strokes in patients whose index stroke was lacunar, all 7 were nonlacunar and 3 were in the territory of the stenotic artery.

CONCLUSIONS

In patients with symptomatic intracranial stenosis, the risk of recurrent stroke was similar in patients who presented with lacunar and nonlacunar strokes, and recurrent strokes in patients presenting with lacunar stroke were typically nonlacunar. These findings suggest that the pathophysiology of these strokes is related to the stenosis rather than small vessel disease. Patients presenting with lacunar strokes should be included in trials investigating secondary prevention for symptomatic intracranial stenosis.

Endovascular treatment of intracranial stenosis

The Gateway balloon-Wingspan stent system is the first, and currently the only "on-label" device for the treatment of symptomatic intracranial stenosis in the United States. In initial single-arm studies, investigators have indicated that this system can be used for the treatment of symptomatic intracranial atherosclerotic disease with high levels of technical success and acceptable periprocedural complication rates, which are comparable with, or better than, those reported for other endovascular techniques. Intermediate- and long-term follow-up data for patients treated with the Wingspan device remain sparse. We critically review the existing data, which characterize the risk profile and efficacy of endovascular interventions for intracranial atherosclerotic disease, as well as the available clinical evidence that could be used to select appropriate patients for treatment.

ABCD2 Score and Large-Artery Atherosclerosis

BACKGROUND AND PURPOSE

Extracranial stenosis (ECS) or intracranial stenosis (ICS) are independent risk factors for stroke after transient ischemic attack (TIA). We examined the association of the age, blood pressure, clinical features, duration of symptoms and diabetes (ABCD2) score, a validated risk prediction model for stroke after TIA, and the presence of ICS or ECS.

METHODS

Vascular imaging and ABCD2 scores were obtained in a retrospective cohort of 77 consecutive patients diagnosed with TIA in a single center emergency department. The association between vascular stenosis and ABCD2 scores and how each related to clinical outcome was examined.

RESULTS

In all, 30 (39.2%) TIA patients had 37 stenotic lesions; 15 (40.5%) stenotic lesions were ICS and 22 (59.5%) stenotic lesions were ECS. A total of 7 patients (9.5%) had both ECS and ICS lesions. Patients with ABCD2 > 3 were more likely to have ICS (odds ratio [OR] = 6.25, confidence interval [CI] 1.39-32.44, P = .009) and ECS (OR = 5.25, CI = 1.56-17.66, P = .005). Of the 37 stenotic lesions, 21 (56.7%) were symptomatic; 4 (19.2%) of these had an ABCD2 ≤ 3. At 7 days, there were 4 ischemic strokes, 3 had previously demonstrated symptomatic stenotic lesions, and all had ABCD2 scores > 3.

CONCLUSIONS

Compared to patients in the low-risk ABCD2 scores, the patients with medium- to high-risk ABCD2 scores are more likely to have symptomatic and asymptomatic vascular stenotic lesions. However, 1 in 5 patients with low-risk ABCD2 score has symptomatic stenotic lesions, indicating ABCD2 score does not identify all patients with symptomatic stenotic lesions.

Indications and applications of arterial stents for stroke prevention in atherosclerotic intracranial stenosis

Intracranial stenosis accounts for 8-10% of all ischemic strokes in North America, a frequency slightly less than that of extracranial carotid stenosis. Among patients presenting with transient ischemic attack or stroke due to intracranial stenosis, the risk of recurrent stroke in the first year after initial symptoms is about 14%. Those with high-risk features (recent stroke and severe stenosis) have up to a 23% rate of recurrent stroke in the year after their initial event. Angioplasty with stenting has emerged as a potential treatment strategy, particularly in high-risk patients, although evidence is currently limited to uncontrolled prospective trials and retrospective case series. In this article, we critically review the clinical results supporting the use of stenting and highlight some key considerations in the application of this technology, including patient selection, procedural management, technical issues, and risk factors for complications and in-stent restenosis.

Collateral circulation in symptomatic intracranial atherosclerosis

Collateral circulation in intracranial atherosclerosis has never been systematically characterized. We investigated collaterals in a multicenter trial of symptomatic intracranial atherosclerotic disease. Baseline angiography was reviewed for information on collaterals in stenoses of the internal carotid, middle cerebral, vertebral, and basilar arteries. A battery of angiographic scales was utilized to evaluate lesion site, arterial patency, antegrade flow, downstream territorial perfusion, and collateral circulation, blinded to all other data. Collateral circulation was adequately available for analysis in 287/569 (50%) subjects with proximal arterial stenoses ranging from 50% to 99%. Extent of collaterals was absent or none in 69%, slow or minimal in 10%, more rapid, yet incomplete perfusion of territory in 7%, complete but delayed perfusion in 11%, and rapid, complete collateral perfusion in 4%. Extent of collateral flow correlated with percentage of stenosis (P<0.0001), with more severe stenoses exhibiting greater compensation via collaterals. Overall, collateral grade increased with diminished antegrade flow across the lesion (thrombolysis in myocardial ischemia) and resultant downstream perfusion (thrombolysis in cerebral infarction) (both P<0.001). Our findings provide the initial detailed description of collaterals across a variety of stenoses, suggesting that collateral perfusion is a pivotal component in pathophysiology of intracranial atherosclerosis and implicating the need for further evaluation in ongoing studies.

10 questions about intracranial atherosclerotic stenosis

Intracranial atherosclerotic disease is one of the most common causes of stroke worldwide, yet treatment for this disease is still uncertain. This article discusses challenges in the diagnosis and treatment of intracranial stenosis by posing 10 commonly asked questions about this disease.

Medical treatment of patients with intracranial atherosclerotic disease

The medical treatment of patients with symptomatic intracranial atherosclerotic disease (ICAD) is directed toward reducing the risk of new ischemic events. The overall strategy is divided into: (1) prevention of occurrence of intraluminal thrombus, with or without embolism; (2) plaque stabilization and regression; and (3) management of atherogenic risk factors. In patients with ICAD, short-term and long-term anticoagulation (compared with aspirin) has not shown to be beneficial. The current guidelines recommend that aspirin monotherapy, the combination of aspirin and extended release dipyridamole, and clopidogrel monotherapy (rather than oral anticoagulants) are all acceptable options in patients with noncardioembolic ischemic stroke and transient ischemic attack. The findings of another pilot trial suggest that symptomatic ICAD is a dynamic lesion and cilostazol may prevent its progression. Overall, the subgroup analysis from randomized trials, provide evidence about benefit of aggressive atherogenic risk factor management among patients with ICAD. Current guidelines recommend statin therapy with intensive lipid-lowering effects for patients with atherosclerotic ischemic stroke or transient ischemic attack with or without known coronary artery disease to reduce the risk of stroke and cardiovascular events.

Intracranial atherosclerotic disease: an update

The consensus conference on intracranial atherosclerosis provides a comprehensive review of the existing literature relevant to the epidemiology, diagnosis, prevention, and treatment of intracranial atherosclerosis, and identifies principles of management and research priorities. Patients who have suffered a stroke or transient ischemic attack attributed to stenosis (50-99%) of a major intracranial artery face a 12 to 14% risk for subsequent stroke during the 2-year period after the initial ischemic event, despite treatment with antithrombotic medications. The annual risk for subsequent stroke may exceed 20% in high-risk groups. In patients with intracranial atherosclerotic disease, short-term and long-term anticoagulation is not superior to antiplatelet treatment. Overall, the subgroup analyses from randomized trials provide evidence about benefit of aggressive atherogenic risk factor management. Intracranial angioplasty with or without stent placement has evolved as a therapeutic option for patients with symptomatic intracranial atherosclerotic disease, particularly those with high-grade stenosis with recurrent ischemic symptoms, medication failure, or both. A multicenter randomized trial is currently under way to compare stent placement with intense medical management for patients with high-grade symptomatic intracranial atherosclerotic disease.

In-hospital complication rates after stent treatment of 388 symptomatic intracranial stenoses: results from the INTRASTENT multicentric registry

BACKGROUND AND PURPOSE

Stenting is increasingly used as an adjunct to medical therapy in symptomatic intracranial stenoses. High periprocedural adverse event rates are one of the limitations of endovascular treatment. Data from the INTRASTENT multicentric registry should demonstrate in-hospital complications at the current stage of clinical development of the stent procedure.

METHODS

Participating centers entered the records of all their consecutive intracranial stent procedures into the database. To determine the clinical outcome in the acute phase, we distinguished transient ischemic attack/nondisabling stroke (modified Rankin Scale <2), disabling stroke, death, and intracranial hemorrhage as clinical complications and analyzed whether they were associated with patient- or stenosis-related risk factors.

RESULTS

Data from 372 patients with 388 stenoses proved 4.8% disabling strokes and 2.2% deaths. Transient or minor events were detected in 5.4% of the cases. Hemorrhagic events (3.5%) occurred more frequently after treatment of middle cerebral artery stenoses (P=0.004) and were associated with significantly higher morbidity and mortality rates. Ischemic strokes by compromise of perforating branches were detected mainly in the posterior circulation. However, the overall rate of severe adverse events was not dependent from location, degree, and morphology of the stenosis or from patient's age, gender, vascular risk factors, or type of qualifying event.

CONCLUSIONS

The complication rates within the registry are within the limits of previously published data. Severe adverse events were equally distributed between potential risk groups with similar rates but different types of main complications in the anterior and posterior circulation.