Prevalence of Intracranial Atherosclerotic Stenosis Using High-Resolution Magnetic Resonance Angiography in the General Population: The Atherosclerosis Risk in Communities Study

BACKGROUND AND PURPOSE

Intracranial atherosclerotic stenosis (ICAS) is a common cause of stroke, but little is known about its epidemiology. We studied the prevalence of ICAS and its association with vascular risk factors using high-resolution magnetic resonance angiography in a US cardiovascular cohort.

METHODS

The Atherosclerosis Risk in Communities (ARIC) study recruited participants from 4 US communities from 1987 to 1989. Using stratified sampling, we selected 1980 participants from visit 5 (2011-2013) for high-resolution 3T-magnetic resonance angiography. All images were analyzed in a centralized laboratory, and ICAS was graded as: no stenosis, <50% stenosis, 50% to 69% stenosis, 70% to 99% stenosis, and complete occlusion. We calculated per-vessel and per-person prevalence of ICAS (weighted for n=6538 visit 5 participants) and also estimated the US prevalence. We used multivariable logistic regression to identify variables independently associated with ICAS.

RESULTS

Subjects who had an adequate magnetic resonance angiography (n=1765) were aged 67 to 90 years, 41% were men, 70% were white, and 29% were black. ICAS was prevalent in 31% of participants and 9% had ICAS ≥50%. Estimated US prevalence of ICAS ≥50% for 65 to 90 years old was 8% for whites and 12% for blacks. Older age, black race, higher systolic blood pressure, and higher low-density lipoprotein cholesterol levels were associated with increased odds of ICAS, whereas higher levels of high-density lipoprotein cholesterol and use of cholesterol-lowering medications were associated with decreased odds of ICAS. Body mass index and smoking were not associated with ICAS.

CONCLUSIONS

The prevalence of ICAS in older adults is high, and it could be a target for primary prevention of stroke and dementia in this population.

Differential Vascular Pathophysiologic Types of Intracranial Atherosclerotic Stroke: A High-Resolution Wall Magnetic Resonance Imaging Study

BACKGROUND AND PURPOSE

Intracranial atherosclerotic stroke (ICAS) has various stroke mechanisms, including branch occlusive disease (BOD), subcortical infarcts caused by parent arterial disease occluding the perforator's orifice, and non-BOD, infarcts beyond the subcortical area caused by artery-to-artery embolism. To test whether these 2 types of ICAS had different vascular pathophysiologies, we compared the high-resolution magnetic resonance imaging characteristics between BOD and non-BOD ICAS.

METHODS

Eighty patients with acute infarcts caused by ICAS of proximal middle cerebral artery or basilar artery without carotid/cardiac embolic sources or nonatherosclerotic causes were enrolled (36 BOD and 44 non-BOD patients). The steno-occlusive intracranial artery at the maximal stenosis was analyzed for vascular remodeling and wall enhancement.

RESULTS

BOD had distinct radiological features in terms of vascular morphology and enhancement. BOD showed a milder stenosis than non-BOD (P<0.001). Positive remodeling was more frequently observed in non-BOD than in BOD (P=0.005). Wall area index was also lower in BOD. Plaque enhancement was observed in all but one non-BOD patient and in one fourth of BOD patients (P=0.003). Although both types showed an eccentric enhancement, this enhancement was more frequently distributed in the BOD group on the side where the perforators arose. As the number of asymptomatic intracranial stenosis increased, the degree of stenosis (rho=0.513, P=0.003) increased in the BOD group, whereas enhanced plaque area (rho=0.343, P=0.030) increased in the non-BOD group.

CONCLUSIONS

Our data indicate that BOD is a common and unique form of ICAS, distinct from non-BOD. These 2 types of ICAS have different vascular pathophysiologies in terms of vascular remodeling and plaque characteristics.

Geographic and sex difference in the distribution of intracranial atherosclerosis in China

BACKGROUND AND PURPOSE

Geographic variation and sex difference in the distribution of intracranial atherosclerosis (ICAS) have not been fully discussed before in Chinese patients with cerebral ischemia. We performed this study with the aim to investigate geographic and sex difference in the distribution of ICAS in China.

METHODS

In this prospective multicenter study, we evaluated 2864 consecutive patients who experienced an acute cerebral ischemia within 7 days of symptom onset in 22 hospitals in China. All the inclusive patients underwent 3-dimensional time-of-flight MR angiography and duplex color Doppler ultrasound or contrast-enhanced MR angiography to document the presence of intracranial or extracranial stenosis. Intracranial large-artery atherosclerosis was defined as ≥50% diameter reduction on MR angiography.

RESULTS

The proportion of patients with ICAS was significantly higher in north China than in south China (50.22% versus 41.88%; P<0.0001). Patients in the north were likely to consume more alcohol and smoke more cigarettes and had significantly higher proportion of diabetes mellitus, family history of stroke, history of cerebral ischemia, heart disease, and higher body mass index. In patients aged >63 years, the percentage of ICAS in women was notably higher than in men (51.51% versus 45.40%; P=0.028). In elderly patients, women had higher proportion of diabetes mellitus, hypertension, hyperlipidemia, and heart disease than men.

CONCLUSIONS

There exists geographic and sex difference in the distribution of symptomatic ICAS in China. Public health measures should strengthen improving social determinants of health and risk factor prevention/control in high-risk populations for decreasing stroke risk.

Transcranial doppler: Technique and common findings (Part 1)

Transcranial Doppler (TCD) can be aptly called as the doctor’s stethoscope of the brain. Since its introduction in 1982, by Rune Aaslid, TCD has evolved as a diagnostic, monitoring, and therapeutic tool. During evaluation of patients with acute ischemic stroke, TCD combined with cervical duplex ultrasonography provides physiological information on the cerebral hemodynamics, which is often complementary to structural imaging. Currently, TCD is the only diagnostic tool that can provide real time information about cerebral hemodynamics and can detect embolization to the cerebral vessels. TCD is a noninvasive, cost-effective, and bedside tool for obtaining information regarding the collateral flow across various branches of the circle of Willis in patients with cerebrovascular disorders. Advanced applications of TCD help in the detection of right-to-left shunts, vasomotor reactivity, diagnosis, and monitoring of vasospasm in subarachnoid hemorrhage and as a supplementary test for confirmation of brain death. This article describes the basic ultrasound physics pertaining to TCD insonation methods, for detecting the flow in intracranial vessels in addition to the normal and abnormal spectral flow patterns.

Stenting for symptomatic intracranial arterial stenosis in China: 1-year outcome of a multicentre registry study

Background and purpose

A multicentre prospective registry study of individually tailored stenting for a patient with symptomatic intracranial atherosclerotic stenosis (ICAS) combined with poor collaterals in China showed that the short-term safety and efficacy of stenting was acceptable. However, it remained uncertain whether the low event rate could be of a long term. We reported the 1-year outcome of this registry study to evaluate the long-term efficacy of individually tailored stenting for patients with severe symptomatic ICAS combined with poor collaterals.

Methods

Patients with symptomatic ICAS caused by 70%-99% stenosis located at the intracranial internal carotid, middle cerebral, intracranial vertebral or basilar arteries combined with poor collaterals were enrolled. Balloon-mounted stent or balloon plus self-expanding stent were selected based on the ease of vascular access and lesion morphology determined by the operators. The primary outcome was the rate of 30-day stroke, transient ischaemic attack and death, and 12-month ischaemic stroke within the same vascular territory, haemorrhagic stroke and vascular death after stenting.

Results

From September 2013 to January 2015, 300 patients (ages 58.3±9.78 years) were recruited. Among them, 159 patients were treated with balloon-mounted stent and 141 with balloon plus self-expanding stent. During the 1-year follow-up, 25 patients had a primary end point event. The probability of primary outcome at 1 year was 8.1% (95% CI 5.3% to 11.7%). In 76 patients with digital subtraction angiography follow-up, 27.6% (21/76) had re-stenosis ≥50% and 18.4% (14/76) had re-stenosis ≥70%. No baseline characteristic was associated with the primary outcome.

Conclusion

The event rate remains low over 1 year of individually tailored stenting for patients with severe symptomatic ICAS combined with poor collaterals. Further randomised trial of comparing individually tailored stenting with best medical therapy is needed.

Trial registration number

NCT01968122; Results.

China Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis (CASSISS): A new, prospective, multicenter, randomized controlled trial in China

BACKGROUND

Patients with symptomatic stenosis of intradural arteries are at high risk for subsequent stroke. Since the SAMMPRIS trial, stenting is no longer recommended as primary treatment; however, the results of this trial, its inclusion criteria and its center selection received significant criticism and did not appear to reflect our experience regarding natural history nor treatment complications rate. As intracranial atherosclerosis (ICAS) is the most common cause for stroke in Asian countries, we are hereby proposing a refined prospective, randomized, multicenter study in an Asian population with strictly defined patient and participating center inclusion criteria.

METHODS

The China Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis (CASSISS) trial is an ongoing, government-funded, prospective, multicenter, randomized trial. It recruits patients with recent TIA or stroke caused by 70%-99% stenosis of a major intracranial artery. Patients with previous stroke related to perforator ischemia will not be included. Only high-volume centers with a proven track record will enroll patients as determined by a lead-in phase. Patients will be randomized (1:1) to best medical therapy alone or medical therapy plus stenting. Primary endpoints are any stroke or death within 30 days after enrollment or after any revascularization procedure of the qualifying lesion during follow-up, or stroke in the territory of the symptomatic intracranial artery beyond 30 days. The CASSISS trial will be conducted in eight sites in China with core imaging lab review at a North American site and aims to have a sample size of 380 participants (stenting, 190; medical therapy, 190). Recruitment is expected to be finished by December 2016. Patients will be followed for at least three years. The trial is scheduled to complete in 2019.

CONCLUSION

In the proposed trial, certain shortcomings of SAMMPRIS including patient and participating center selection will be addressed. The present manuscript outlines the rationale and design of the study. We estimate that this trial will allow for a critical reappraisal of the role of intracranial stenting for selected patients in high-volume centers.

"Imaging Evaluation of Collaterals in the Brain: Physiology and Clinical Translation"

The cerebral collateral circulation is a network of blood vessels designed to preserve cerebral blood flow when primary routes fail. Though recognized for hundreds of years, the beneficial influence of collateral flow has now gained significant attention due to widely available, rapid, and real-time non-invasive imaging techniques. Multimodal CT and MRI based techniques, with angiographic and perfusion assessments, are becoming mainstays in the care of patients with ischemic brain disease. These methods allow for precise delineation of the structural and functional aspects of cerebral blood flow and as such provide valuable information that can inform the diagnosis and treatment of cerebral ischemia, in both the acute and chronic setting.

Association of intracranial atherosclerotic stenosis with severity of white matter hyperintensities

BACKGROUND AND PURPOSE

White matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) have been linked to small-vessel disease, but the precise pathogenesis underlying WMHs remains unclear. Studies about an association of WMHs with extracranial atherosclerotic stenosis (ECAS) showed conflicting results and the relationship of WMHs with intracranial atherosclerotic stenosis (ICAS) is uncertain.

METHODS

A cross-sectional study of 679 consecutive Korean patients with acute ischaemic stroke (mean age 67.8 ± 12.6; 395 males) who underwent brain MRI/MR angiography was conducted. Severity of deep WMHs (d-WMHs, n = 560) and periventricular WMHs (p-WMHs, n = 590) was rated separately and compared across three groups: ICAS (n = 318), ECAS (n = 71) and no cerebral atherosclerotic stenosis (NCAS) (n = 290).

RESULTS

The ICAS group showed a higher d-WMH/p-WMH score (1.62 ± 0.85/1.65 ± 0.79) than both the ECAS (1.25 ± 0.87/1.23 ± 0.78) and NCAS (1.19 ± 0.92/1.24 ± 0.81) groups (P < 0.001 for all). Patients with a greater number of ICAS were more likely to have higher scores of d-WMH/p-WMH (P < 0.001 for all). Patients with higher scores of d-WMH/p-WMH had a higher incidence of ICAS (P < 0.001 for all), but not of ECAS or NCAS. In multivariable analysis, a dose-response relationship was observed between the extent of ICAS versus WMHs. Compared with one ICAS lesion, for d-WMHs the odds ratio (OR) = 2.61 [95% confidence interval (CI) 0.95-7.20] for two ICAS lesions and OR = 3.37 (1.10-10.32) for ≥3 ICAS lesions; whilst for p-WMHs (score ≥2) OR = 1.70 (95% CI 0.96-2.98) for two ICAS lesions and OR = 2.02 (1.15-3.55) for ≥3 ICAS lesions.

CONCLUSION

ICAS is independently associated with progressively greater WMH burden. The association of ICAS with WMH severity appears to be stronger than that of ECAS/NCAS in the Korean (Asian) stroke population.

Caveolin-1, Ring finger protein 213, and endothelial function in Moyamoya disease

BACKGROUND

Moyamoya disease is a unique cerebrovascular occlusive disease of unknown etiology. Ring finger protein 213 (RNF213) was identified as a susceptibility gene for Moyamoya disease in East Asian countries. However, the pathogenesis of Moyamoya disease remains unclear.

METHODS

We prospectively analyzed clinical data for 139 patients with Moyamoya disease (108 bilateral Moyamoya disease, 31 unilateral Moyamoya disease), 61 patients with intracranial atherosclerotic stroke, and 68 healthy subjects. We compared the genetic (RNF213 variant) and protein biomarkers for caveolae (caveolin-1), angiogenesis (vascular endothelial growth factor (VEGF) and receptor (VEGFR2), and antagonizing cytokine (endostatin)) and endothelial dysfunction (asymmetric dimethylarginine (ADMA), and nitric oxide and its metabolites (nitrite and nitrate)) between patients with Moyamoya disease and intracranial atherosclerotic stroke. We then performed path analysis to evaluate whether a certain protein biomarker mediates the association between genes and Moyamoya disease.

RESULTS

Caveolin-1 level was decreased in patients with Moyamoya disease and markedly decreased in RNF213 variant carriers. Circulating factors such as VEGF and VEGFR2 did not differ among the groups. Markers for endothelial dysfunction were significantly higher in patients with intracranial atherosclerotic stroke but normal in those with Moyamoya disease. Path analysis showed that the presence of the RNF213 variant was associated with caveolin-1 levels that could lead to Moyamoya disease. The level of combined marker of Moyamoya disease (caveolin-1) and intracranial atherosclerotic stroke (ADMA, an endothelial dysfunction marker) predicted Moyamoya disease with good sensitivity and specificity.

CONCLUSION

Our results suggest that Moyamoya disease is a caveolae disorder but is not related to endothelial dysfunction or dysregulation of circulating cytokines.

Stenting for intracranial stenosis: potential future for the prevention of disabling or fatal stroke

Intracranial stenosis is a common cause of ischaemic strokes, in particular, in the Asian, African and Hispanic populations. The randomised multicentre study Stenting and Aggressive Medical Management for the Prevention of Recurrent stroke in Intracranial Stenosis (SAMMPRIS) showed 14.7% risk of stroke or death in the stenting group versus 5.8% in the medical group at 30 days, and 23% in the stenting group versus 15% in the medical group at a median follow-up of 32.4 months. The results demonstrated superiority of medical management over stenting and have almost put the intracranial stenting to rest in recent years. Of note, 16 patients (7.1%) in the stenting group had disabling or fatal stroke within 30 days mostly due to periprocedural complications as compared with 4 patients (1.8%) in the medical group. In contrast, 5 patients (2.2%) in the stenting group and 14 patients (6.2%) in the medical group had a disabling or fatal stroke beyond 30 days, indicating significant benefit of stenting if periprocedural complications can be reduced. Recently, the results of the Chinese Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis trial and the Wingspan Stent System Post Market Surveillance Study (WEAVE trial) showed 2%-2.7% periprocedural complications. It is time to evaluate the role of intracranial stenting for the prevention of disabling or fatal stroke.

Intracranial stenosis: impact of randomized trials on treatment preferences of US neurologists and neurointerventionists

BACKGROUND AND PURPOSE

Medical and endovascular treatment options for stroke prevention in patients with symptomatic intracranial stenosis have evolved over the past several decades, but the impact of 2 major multicenter randomized stroke prevention trials on physician practices has not been studied. We sought to determine changes in US physician treatment choices for patients with intracranial atherosclerotic stenosis (ICAS) following 2 NIH-funded clinical trials that studied medical therapies (antithrombotic agents and risk factor control) and percutaneous transluminal angioplasty and stenting (PTAS).

METHODS

Anonymous surveys on treatment practices in patients with ICAS were sent to physicians at 3 time points: before publication of the NIH-funded Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial (pre-WASID survey, 2004), 1 year after WASID publication (post-WASID survey, 2006) and 1 year after the publication of the NIH-funded Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial (post-SAMMPRIS survey, 2012). Neurologists were invited to participate in the pre-WASID survey (n=525). Neurologists and neurointerventionists were invited to participate in the post-WASID (n=598) and post-SAMMPRIS (n=2,080) surveys. The 3 surveys were conducted using web-based survey tools delivered by E-mail, and a fax-based response form delivered by E-mail and conventional mail. Data were analyzed using the χ2 test.

RESULTS

Before WASID, there was equipoise between warfarin and aspirin for stroke prevention in patients with ICAS. The number of respondents who recommended antiplatelet treatment for ICAS increased across all 3 surveys for both anterior circulation (pre-WASID=44%, post-WASID=85%, post-SAMMPRIS=94%) and posterior circulation (pre-WASID=36%, post-WASID=74%, post-SAMMPRIS=83%). The antiplatelet agent most commonly recommended after WASID was aspirin, but after SAMMPRIS it was the combination of aspirin and clopidogrel. The percentage of neurologists who recommended PTAS in >25% of ICAS patients increased slightly from pre-WASID (8%) to post-WASID surveys (12%), but then decreased again after SAMMPRIS (6%). The percentage of neurointerventionists who recommended PTAS in >25% of ICAS patients decreased from post-WASID (49%) to post-SAMMPRIS surveys (17%).

CONCLUSIONS

The surveyed US physicians' recommended treatments for ICAS differed over the 3 survey periods, reflecting the results of the 2 NIH-funded clinical trials of ICAS and suggesting that these clinical trials changed practice in the USA.

Intracranial stenosis in cognitive impairment and dementia

Intracranial stenosis is a common vascular lesion observed in Asian and other non-Caucasian stroke populations. However, its role in cognitive impairment and dementia has been under-studied. We, therefore, examined the association of intracranial stenosis with cognitive impairment, dementia and their subtypes in a memory clinic case-control study, where all subjects underwent detailed neuropsychological assessment and 3 T neuroimaging including three-dimensional time-of-flight magnetic resonance angiography. Intracranial stenosis was defined as ≥50% narrowing in any of the intracranial arteries. A total of 424 subjects were recruited of whom 97 were classified as no cognitive impairment, 107 as cognitive impairment no dementia, 70 vascular cognitive impairment no dementia, 121 Alzheimer's Disease, and 30 vascular dementia. Intracranial stenosis was associated with dementia (age/gender/education - adjusted odds ratios (OR): 4.73, 95% confidence interval (CI): 1.93-11.60) and vascular cognitive impairment no dementia (OR: 3.98, 95% CI: 1.59-9.93). These associations were independent of cardiovascular risk factors and MRI markers. However, the association with Alzheimer's Disease and vascular dementia became attenuated in the presence of white matter hyperintensities. Intracranial stenosis is associated with vascular cognitive impairment no dementia independent of MRI markers. In Alzheimer's Disease and vascular dementia, this association is mediated by cerebrovascular disease. Future studies focusing on perfusion and functional markers are needed to determine the pathophysiological mechanism(s) linking intracranial stenosis and cognition so as to identify treatment strategies.

CYP2C19 and CES1 polymorphisms and efficacy of clopidogrel and aspirin dual antiplatelet therapy in patients with symptomatic intracranial atherosclerotic disease

OBJECT Symptomatic intracranial atherosclerotic disease (ICAD) has a high risk of recurrent stroke. Genetic polymorphisms in CYP2C19 and CES1 are associated with adverse outcomes in cardiovascular patients, but have not been studied in ICAD. The authors studied CYP2C19 and CES1 single-nucleotide polymorphisms (SNPs) in symptomatic ICAD patients. METHODS Genotype testing for CYP2C19*2, (*)3, (*)8, (*)17 and CES1 G143E was performed on 188 adult symptomatic ICAD patients from 3 medical centers who were medically managed with clopidogrel and aspirin. Testing was performed prospectively at 1 center, and retrospectively from a DNA sample biorepository at 2 centers. Multiple logistic regression and Cox regression analysis were performed to assess the association of these SNPs with the primary endpoint, which was a composite of transient ischemic attack (TIA), stroke, myocardial infarction, or death within 12 months. RESULTS The primary endpoint occurred in 14.9% of the 188 cases. In multiple logistic regression analysis, the presence of the CYP2C19 loss of function (LOF) alleles *2, *3, and *8 in the medically managed patients was associated with lower odds of primary endpoint compared with wild-type homozygotes (odds ratio [OR] 0.13, 95% CI 0.03-0.62, p = 0.0101). Cox regression analysis demonstrated the CYP2C19 LOF carriers had a lower risk for the primary endpoint, with hazard ratio (HR) of 0.27 (95% CI 0.08-0.95), p = 0.041. A sensitivity analysis of a secondary composite endpoint of TIA, stroke, or death demonstrated a significant trend in multiple logistic regression analysis of CYP2C19 variants, with lower odds of secondary endpoint in patients carrying at least 1 LOF allele (*2, *3, *8) than in wild-type homozygotes (OR 0.27, 95% CI 0.06-1.16, p = 0.078). Cox regression analysis demonstrated that the carriers of CYP2C19 LOF alleles had a lower risk forthe secondary composite endpoint (HR 0.22, 95% CI 0.05-1.04, p = 0.056). CONCLUSIONS This is the first study examining genetic variants and their effects in symptomatic ICAD. Variant alleles of CYP2C19 (*2, *3, *8) were associated with lower odds of the primary and secondary composite endpoints. However, the direction of the association was opposite of what is expected based on this SNP. This may reflect an incomplete understanding of this genetic variation and its effect in symptomatic ICAD and warrants further investigations.

Emergency Intracranial Stenting in Acute Stroke: Predictors for Poor Outcome and for Complications

Background

Stent‐retriever thrombectomy is the first‐line therapy in acute stroke with intracranial large vessel occlusion. In case of failure of stent‐retriever thrombectomy, rescue stent angioplasty might be the only treatment option to achieve permanent recanalization. This study aims at identifying predictors for poor outcome and complications in a large, multicenter cohort receiving rescue stent angioplasty.

Methods and Results

We performed a retrospective analysis of patients with large vessel occlusion who were treated with rescue stent angioplasty after stent‐retriever thrombectomy between 2012 and 2018 in 7 neurovascular centers. We defined 2 binary outcomes: (1) functional clinical outcome (good modified Rankin Scale, 0–2; and poor modified Rankin Scale, 4–6) and (2) early symptomatic intracerebral hemorrhage. Impacts of clinical, radiological, and interventional parameters on outcomewere assessed in uni‐ and multivariable logistic regression models. Two hundred ten patients were included with target vessels located within the anterior circulation (136 of 210; 64.8%) and posterior circulation (74 of 210; 35.2%). Symptomatic intracerebral hemorrhage occured in 22 patients, 86.4% (19 of 22) after anterior and 13.6% (3 of 22) after posterior circulation large vessel occlusion. Good functional outcome was observed in 44.8% (73 of 163). A higher National Institutes of Health Stroke Scale on admission (adjusted odds ratio, 1.10; P=0.002), a higher premorbid modified Rankin Scale (adjusted odds ratio, 2.02; P=0.049), and a modified Thrombolysis in Cerebral Infarction score of 0 to 2a after stenting (adjusted odds ratio, 23.24; P<0.001) were independent predictors of poor functional outcome.

Conclusions

Use of rescue stent angioplasty can be considered for acute intracranial large vessel occlusion in cases after unsuccessful stent‐retriever thrombectomy. Likelihood of symptomatic intracerebral hemorrhage is higher in anterior circulation stroke.

Nontraumatic convexal subarachnoid hemorrhage concomitant with acute ischemic stroke

BACKGROUND

Nontraumatic convexal subarachnoid hemorrhage (cSAH) rarely occurs subsequent to acute ischemic stroke. The incidence, clinical background characteristics, and outcomes in acute ischemic stroke patients with cSAH were investigated.

METHODS

Our stroke center database was reviewed to identify patients with acute ischemic stroke/transient ischemic attack (TIA) who demonstrated acute cSAH within 14 days of admission between 2005 and 2011. Background characteristics, clinical course, and outcomes at discharge and 3 months after onset were investigated in these patients.

RESULTS

Of 4953 acute stroke/TIA patients, cSAH was observed in 8 (.14%) patients (7 men, mean age 71 years): 7 were detected incidentally, and the other was found immediately after a convulsion. Two patients died during their hospital stay, 1 died after discharge, and 3 were dependent at 3 months. Major artery occlusion or severe stenosis was observed in 5 patients. Two patients subsequently developed subcortical hemorrhage. On gradient echo imaging, lobar cerebral microbleeds were observed in 2 patients, and chronic superficial siderosis was observed in 2 patients.

CONCLUSIONS

In this retrospective review of cases with ischemic stroke and cSAH, over half of patients had occlusion of major arteries. Cerebral amyloid angiopathy was suggested by magnetic resonance imaging findings and subsequent events in 3 patients. The overall outcome was unfavorable although the causal relationship with cSAH was unclear.

Ring Finger Protein 213 Variant and Plaque Characteristics, Vascular Remodeling, and Hemodynamics in Patients With Intracranial Atherosclerotic Stroke: A High-Resolution Magnetic Resonance Imaging and Hemodynamic Study

Background

Intracranial atherosclerotic stroke is prevalent in Asians. We hypothesized that patients with the ring finger protein 213 (RNF213) variant, a susceptibility locus for moyamoya disease in Asians, have different neuroimaging characteristics in terms of the vessel wall and hemodynamics.

Methods and Results

We analyzed consecutive patients with ischemic events in middle cerebral artery distribution and relevant plaques of the distal internal carotid artery or proximal middle cerebral artery on high‐resolution magnetic resonance imaging. Patients with carotid/cardiac sources of embolism or moyamoya disease were excluded. High‐resolution magnetic resonance imaging features (eg, outer vessel diameters and plaque characteristics) and fractional flow (as measured by adjusted signal intensity ratio on time‐of‐flight magnetic resonance angiography) were compared between RNF213 p.Arg4810Lys variant carriers and noncarriers. Among 144 patients included, 44 (29.9%) had the RNF213 variant. Clinical characteristics, including age, sex, body mass index, and vascular risk factors, were not significantly different between RNF213 variant carriers and noncarriers. However, the outer vessel diameter was smaller in RNF213 variant carriers than in noncarriers (P<0.0001 for middle cerebral artery of relevant stenosis [2.05‐mm analysis of RNF213 gene for moyamoya disease in the Chinese HAN population 2.75 mm]; P<0.0001 for contralateral side [2.42  versus 3.00 mm] and P<0.001 for basilar artery [3.19 versus 3.53 mm]). Other high‐resolution magnetic resonance imaging features, including plaque morphology and eccentricity, were not significantly different. Fractional flow was diminished in patients with smaller‐diameter intracranial arteries with a similar degree of stenosis.

Conclusions

The RNF213 variant may be associated with vasculogenesis, but not with atherogenesis. Patients with this variant had small intracranial arteries predisposing hemodynamic compromise in the presence of intracranial atherosclerosis. In addition to antiatherosclerotic strategies, further studies are warranted to develop novel therapeutic strategies against RNF213 vasculopathy in Asians.

See Editorial Liu and Gutierrez

Treatment and imaging of intracranial atherosclerotic stenosis: current perspectives and future directions

BACKGROUND AND PURPOSE

Intracranial atherosclerosis is a common cause of stroke worldwide. It results in ischemic stroke due to different mechanisms including artery-to-artery embolism, in situ thrombo-occlusion, occlusion of perforating arteries, and hemodynamic failure. In this review, we present an overview of current treatment and imaging modalities in intracranial atherosclerotic stenosis.

METHODS

PubMed was searched for relevant articles in English that evaluated the treatment and imaging of intracranial atherosclerotic stenosis (ICAS).

RESULTS

Aggressive medical management, consisting of dual antiplatelet therapy and intensive risk factor management, is important in patients with ICAS because of a substantial risk of recurrent stroke, approximately 20% in the first year, in patients on aspirin or warfarin alone. Recent trials have suggested that, aggressive medical therapy results in better outcome as compared with intracranial stenting. However, the question remains what the optimal treatment strategy would be in patients with recurrent strokes in the setting of failed aggressive medical therapy. Moreover, controversy exists whether a subgroup of patients with symptomatic ICAS could benefit from intracranial stenting if selection is based on radiological evidence of hemodynamic failure. With regard to imaging, transcranial Doppler ultrasound and magnetic resonance angiography are useful screening tests for exclusion of ICAS, but need confirmation by other imaging modalities when stenosis is suggested. Computed tomography angiography has a high positive and negative predictive value for detection of intracranial luminal stenosis of 50% or higher, but performs worse than digital subtraction angiography with regard to establishing the exact degree of luminal stenosis. Novel imaging techniques including high-resolution CT and MRI better identify plaque characteristics than conventional imaging methods.

CONCLUSIONS

Currently, aggressive medical management remains the standard of care for patients with ICAS. Further research is needed to identify high-risk subgroups and to develop more effective treatments for ICAS patients.

What Threshold Defines Penumbral Brain Tissue in Patients with Symptomatic Anterior Circulation Intracranial Stenosis: An Exploratory Analysis

BACKGROUND AND PURPOSE

Impaired distal perfusion predicts neurological deterioration in large artery atherosclerosis. We aim to determine the optimal threshold of Tmax delay on perfusion imaging that is associated with neurological deterioration in patients with symptomatic proximal anterior circulation large artery stenosis.

METHODS

Data were abstracted from a prospective ischemic stroke database of consecutively enrolled patients with symptomatic proximal intracranial stenosis (internal carotid artery or M1 segment of the middle cerebral artery) who underwent magnetic resonance perfusion imaging within 24 hours of symptom onset during a 15-month period. Tissue volumes of perfusion delay Tmax 0-4 seconds, Tmax > 4 seconds, Tmax > 6 seconds, and Tmax > 8 seconds were calculated using an automated approach. A target mismatch (penumbra-core) was defined as ≥15mL of brain tissue using each of the Tmax threshold categories. The outcome was neurological deterioration at 30 days defined as new or worsening neurological deficits that are not attributed to a nonvascular etiology.

RESULTS

Among 52 patients with symptomatic intracranial stenosis, 26 patients met inclusion criteria. Neurological deterioration was associated with target mismatch profile defined according to Tmax > 6 seconds (66.7% [6/9] vs. 5.9% [1/17], P < .01) and Tmax >8 seconds (57.1% [4/7] vs. 15.8% [3/19], P = .05] but not according to Tmax > 4 seconds (27.3% [6/17] vs. 11.1% [1/9], P = .35].

CONCLUSIONS

A target mismatch profile using Tmax > 6 seconds may define tissue at risk in patients with acute symptomatic proximal anterior circulation intracranial stenosis. More studies are needed to confirm our findings.

Design of the Vitesse Intracranial Stent Study for Ischemic Therapy (VISSIT) trial in symptomatic intracranial stenosis

BACKGROUND

Patients with high-grade symptomatic intracranial stenosis (≥ 70%) have an increased risk of recurrent stroke despite medical treatment with antiplatelet or anticoagulant therapy. Intracranial stenting has been proposed as a viable treatment option for this high-risk patient population; however, evaluation of this therapy in randomized multicenter trials is needed. In this article, we present the design and methods of the Vitesse Intracranial Stent Study for Ischemic Therapy (VISSIT) trial for symptomatic intracranial stenosis.

METHODS

The VISSIT trial is a randomized control study designed to evaluate the safety, probable benefit, and effectiveness of the PHAROS Vitesse neurovascular balloon-expandable stent system plus medical therapy versus medical therapy alone in patients with cerebral or retinal ischemia due to neurovascular stenosis (≥ 70%) for preventing the primary composite end point: stroke in the same territory (distal to the target lesion) as the presenting event within 12 months of randomization or hard transient ischemic attack in the same territory (distal to the target lesion) as the presenting event from day 2 through month 12 postrandomization.

RESULTS

Enrollment began in February 2009 and was halted in January 2012 with 112 subjects enrolled into the study. Clinical follow-up will continue for the planned period of 12 months postrandomization.

CONCLUSIONS

The VISSIT trial may provide valuable insight into the use of balloon-expandable intracranial stent as a treatment option for high-risk patients. Lessons learned from this trial may better guide future clinical trial design on best patient selection, stenting techniques, and periprocedural management.

Variable impact of CSF flow suppression on quantitative 3.0T intracranial vessel wall measurements

BACKGROUND

Flow suppression techniques have been developed for intracranial (IC) vessel wall imaging (VWI) and optimized using simulations; however, simulation results may not translate in vivo.

PURPOSE

To evaluate experimentally how IC vessel wall and lumen measurements change in identical subjects when evaluated using the most commonly available blood and cerebrospinal fluid (CSF) flow suppression modules and VWI sequences.

STUDY TYPE

Prospective.

POPULATION/SUBJECTS

Healthy adults (n = 13; age = 37 ± 15 years) were enrolled.

FIELD STRENGTH/SEQUENCE

A 3.0T 3D T1 /proton density (PD)-weighted turbo-spin-echo (TSE) acquisition with post-readout anti-driven equilibrium module, with and without Delay-Alternating-with-Nutation-for-Tailored-Excitation (DANTE) was applied. DANTE flip angle (8-12°) and TSE refocusing angle (sweep = 40-120° or 50-120°) were varied.

ASSESSMENT

Basilar artery and internal carotid artery (ICA) wall thicknesses, CSF signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and signal ratio (SR) were assessed. Measurements were made by two readers (radiology resident and board-certified neuroradiologist).

STATISTICAL TESTS

A Wilcoxon signed-rank test was applied with corrected two-sided P < 0.05 required for significance (critical P = 0.008, 0.005, and 0.05 for SNR/CNR, SR, and wall thickness, respectively).

RESULTS

A TSE pulse sweep = 40-120° and sweep = 50-120° provided similar (P = 0.55) CSF suppression. Addition of the DANTE preparation reduced CSF SNR from 17.4 to 6.7, thereby providing significant (P < 0.008) improvement in CSF suppression. The DANTE preparation also resulted in a significant (P < 0.008) reduction in vessel wall SNR, but variable vessel wall to CSF CNR improvement (P = 0.87). There was a trend for a difference in blood SNR with vs. without DANTE (P = 0.05). The outer vessel wall diameter and wall thickness values were lower (P < 0.05) with (basilar artery 4.45 mm, 0.81 mm, respectively) vs. without (basilar artery 4.88 mm, 0.97 mm, respectively) DANTE 8°.

DATA CONCLUSION

IC VWI with TSE sweep = 40-120° and with DANTE flip angle = 8° provides the best CSF suppression and CNR of the approaches evaluated. However, improvements are heterogeneous, likely owing to intersubject vessel pulsatility and CSF flow variations, which can lead to variable flow suppression efficacy in these velocity-dependent modules.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;48:1120-1128.

Angioplasty and Stenting of Intracranial Arterial Stenosis in Perforator-Bearing Segments: A Comparison Between the Anterior and the Posterior Circulation

Background and Purpose: Subgroup analysis of the SAMMPRIS trial showed a higher rate of periprocedural perforator strokes with the Wingspan stent in the basilar artery in patients with symptomatic intracranial atherosclerotic stenosis (ICAS). It remains unclear whether angioplasty (PTA) alone or in combination with other stent types (PTAS) will yield similar results in perforator-bearing segments of the anterior and posterior circulation.

Methods: We retrospectively analyzed the periprocedural complication rate, long term outcome and stroke etiology in 59 consecutive patients with ICAS of the middle cerebral artery (79 treatments) and 67 patients with ICAS of the intracranial vertebral and basilar artery (76 treatments) treated with PTA or PTAS from 2007 to 2015 in a high-volume neuro-interventional center.

Results: Periprocedural symptomatic ischemic strokes occurred significantly more often in patients with posterior vs. anterior ICAS treatment (14.5 vs. 5.1%, p = 0.048). During a mean follow-up period of 19 (±23.7) months, 5 recurrent ischemic and 2 hemorrhagic strokes (10.4%) occurred in the territory of the treated artery in posterior circulation compared to 2 ischemic strokes in the anterior circulation (3.4%, p = 0.549). Overall, significantly more patients treated for a posterior ICAS suffered a periprocedural or follow-up stroke [25% vs. 11.4%, p = 0.024]. Periprocedural ischemic strokes were predominantly perforator strokes (73.3%), while all ischemic strokes during follow-up were caused by distal embolization (57.1%) or delayed stent occlusion (42.9%). There was no difference between PTA alone and PTAS.

Conclusion: The periprocedural and long-term symptomatic stroke rate was significantly higher in the treatment of perforator-bearing arteries in the posterior circulation. There was no difference between PTA alone or PTAS.

Thirty-Day Outcomes of Resolute Onyx Stent for Symptomatic Intracranial Stenosis: A Multicenter Propensity Score-Matched Comparison With Stenting Versus Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis Trial

BACKGROUND

Symptomatic intracranial atherosclerotic disease (sICAD) is estimated to cause 10% of strokes annually in the United States. However, treatment remains a challenge with several different stenting options studied in the past with unfavorable results.

OBJECTIVE

To report the 30-day stroke and/or death rate associated with intracranial stent placement for sICAD using Resolute Onyx Zotarolimus-Eluting Stent (RO-ZES) and provide a comparison with the results of Stenting Versus Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial.

METHODS

Prospectively maintained databases across 8 stroke centers were used to identify adult patients treated with RO-ZES for sICAD between January 2019 and December 2021. Primary end point was composite of 30-day stroke, intracerebral hemorrhage, and/or death. Propensity score matching was performed using age, hypertension, lipid disorder, cigarette smoking, and symptomatic target vessel to create a matched group for comparison between RO-ZES and the SAMMPRIS medical management and treatment groups (SAMMPRIS percutaneous angioplasty and stenting [S-PTAS]).

RESULTS

A total of 132 patients met the inclusion criteria for analysis (mean age: 64.2 years). Mean severity of stenosis was 81.4% (±11.4%). A total of 4 (3.03%) stroke and/or deaths were reported within 30 days of treatment in the RO-ZES group compared with 6.6% in the SAMMPRIS medical management group (OR [odds ratio] 2.26, 95% CI 0.7-9.56, P = .22) and 15.6% in the S-PTAS group (OR 5.9, 95% CI 2.04-23.4, P < .001). Propensity score match analysis of 115 patients in each group demonstrated 30-day stroke and/or death rate of 2.6% in the RO-ZES group and 15.6% in the S-PTAS group (OR 6.88, 95% CI 1.92-37.54, P < .001).

CONCLUSION

Patients treated with RO-ZES had a relatively low 30-day stroke and/or death rate compared with the S-PTAS group. Further large-scale prospective studies are warranted to evaluate the safety and efficacy of RO-ZES for the treatment of sICAD.

3D printing of intracranial artery stenosis based on the source images of magnetic resonance angiograph

BACKGROUND AND PURPOSE

Three dimensional (3D) printing techniques for brain diseases have not been widely studied. We attempted to 'print' the segments of intracranial arteries based on magnetic resonance imaging.

METHODS

Three dimensional magnetic resonance angiography (MRA) was performed on two patients with middle cerebral artery (MCA) stenosis. Using scale-adaptive vascular modeling, 3D vascular models were constructed from the MRA source images. The magnified (ten times) regions of interest (ROI) of the stenotic segments were selected and fabricated by a 3D printer with a resolution of 30 µm. A survey to 8 clinicians was performed to evaluate the accuracy of 3D printing results as compared with MRA findings (4 grades, grade 1: consistent with MRA and provide additional visual information; grade 2: consistent with MRA; grade 3: not consistent with MRA; grade 4: not consistent with MRA and provide probable misleading information). If a 3D printing vessel segment was ideally matched to the MRA findings (grade 2 or 1), a successful 3D printing was defined.

RESULTS

Seven responders marked "grade 1" to 3D printing results, while one marked "grade 4". Therefore, 87.5% of the clinicians considered the 3D printing were successful.

CONCLUSIONS

Our pilot study confirms the feasibility of using 3D printing technique in the research field of intracranial artery diseases. Further investigations are warranted to optimize this technique and translate it into clinical practice.

The case for angioplasty in patients with symptomatic intracranial atherosclerosis

Intracranial atherosclerotic disease (ICAD) is likely the most common cause of stroke worldwide and remains highly morbid even with highly monitored medical therapy. Recent results of the SAMMPRIS trial, which randomized patients to stenting plus aggressive medical management versus aggressive medical management alone have shown that additional treatment of intracranial atherosclerotic lesions with the Wingspan stent is inferior to aggressive medical management alone. In light of these results, there has been renewed interest in angioplasty alone to treat symptomatic ICAD. This article will briefly review the natural history of ICAD and discuss the possible future for endovascular treatment of ICAD with primary intracranial angioplasty in appropriately selected patients.