Prospective study of symptomatic atherothrombotic intracranial stenoses: The GESICA Study

Stroke recurrence in the different subtypes of ischemic stroke. The importance of the intracranial disease

The aim of the study was to analyze the long-term recurrence rate in patients with a first-ever ischemic stroke secondary to intracranial large artery atherosclerosis (LAA) in a Brazilian population.

METHODS

All stroke patients admitted to the hospital between October 2012 and September 2015 were evaluated. The stroke mechanism subtypes were classified as cardioembolism, LAA, small-vessel occlusion, other determined etiologies, and stroke of undetermined etiology.

RESULTS

The 359 first-ever ischemic stroke patients were followed up for a mean time of 21.6 ± 15.1 months. The LAA intracranial (38.9%) and extracranial (24.6%) stroke patients presented with a higher stroke recurrence. Intracranial LAA [HR, 10.2 (3.6-29.1); p < 0.001] and extracranial LAA [HR, 5.05 (1.79-14.2); p = 0.002] were the only conditions to show positive correlation with the recurrence rate, after adjusting for risk factors, thrombolysis, and National Institutes of Health Stroke Scale score at admission.

CONCLUSION

Intracranial LAA presents a higher incidence of recurrence of ischemic stroke when compared with other etiologies in a Southern Brazilian population.

[Stroke prevention]

Prevention is essential to stroke management because of the high risk of recurrence. Stroke incidence is increased by known risk factors, which can be prevented. Cardiovascular prevention after stroke or TIA also includes aetiology-specific treatment, when it is known. Endovascular treatment is not indicated as a first-line treatment for atheromatous cervical or intracranial stenosis. Endovascular or surgical treatment is not indicated as first-line treatment for cervical arterial dissection because of its minor risk of stroke recurrence.

Patients with Acute Ischemic Cerebrovascular Disease with Coronary Artery Stenosis Have More Diffused Cervicocephalic Atherosclerosis

Aims: Coronary artery stenosis (CAS) ≥ 50% frequently coexists in patients with acute ischemic cerebrovascular disease (AICVD), which portends unfavorable outcomes. We sought to examine whether patients with AICVD with CAS had more severe and more diffused cervicocephalic atherosclerosis (CA).

Methods: Patients with AICVD were consecutively enrolled and underwent simultaneous computed tomography angiography (CTA) of the coronary and cervicocephalic arteries. A total of 140 patients were divided into “AICVD + CAS” and “AICVD only” groups according to whether CTA showed stenosis of ≥ 50% in at least one coronary arterial segment. The relationship of the presence of CAS with the severity and extent of CA were examined.

Results: The CA severity characteristics, including the presence of stenosis ≥ 50% and the grade of the most severe stenotic segment, were not significantly different between the two groups. Regarding the extent of CA, the presence of stenosis ≥ 50% in both sides (adjusted odds ratio [OR]: 4.29, 95% confidence interval [CI]: 1.67–10.98), both extracranial and intracranial (adjusted OR: 5.26, 95% CI: 2.24–12.35), both anterior and posterior circulation (adjusted OR: 5.29, 95% CI: 2.22–12.64), and the number of stenotic segments ≥ 50% in cervicocephalic arteries (adjusted OR: 1.58, 95% CI: 1.28–1.96) were associated with CAS in patients with AICVD, independently of clinical demographics and CA severity characteristics.

Conclusion: CA was similarly severe in patients with AICVD with and without CAS, but those with CAS had significantly more diffused CA. The extent of CA and CAS were mutual indicators in patients with AICVD, irrespective of CA severity.

Type and Duration of Exercise in the SAMMPRIS Trial

BACKGROUND

Analyses from the Stenting and Aggressive Medical management for prevention of Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial showed that good control of vascular risk factors (systolic blood pressure, low-density lipoprotein, and exercise) was associated with fewer vascular events and exercise had the biggest impact on the outcome. We sought to determine the type and duration of exercise performed by SAMMPRIS patients during the trial.

METHODS

SAMMPRIS aggressive medical management included a telephonic lifestyle modification program, INTERVENT, that was provided free of charge to all subjects during the study. We analyzed self-reported data collected by INTERVENT on the patients' type and duration of exercise from baseline (n=394) to 3 years (n=132). We calculated the mean duration for each exercise type at each time period and then compared the change in exercise duration from baseline using paired t tests and Wilcoxon signed-rank tests.

RESULTS

Walking was the most common form of exercise at all time points, as measured by both the duration of exercise and the number of patients performing the exercise. The mean duration of walking and other aerobic activities increased significantly from baseline to all other time points.

CONCLUSIONS

The type of self-reported exercise performed by SAMMPRIS patients included mostly walking or other aerobic activity and increased significantly during follow-up.

Intracranial atherosclerotic disease

Intracranial atherosclerosis (ICAS) is a progressive pathological process that causes progressive stenosis and cerebral hypoperfusion and is a major cause of stroke occurrence and recurrence around the world. Multiple factors contribute to the development of ICAS. Angiography imaging techniques can improve the diagnosis of and the selection of appropriate treatment regimens for ICAS. Neither aggressive medication nor endovascular interventions can eradicate stroke recurrence in patients with ICAS. Non-pharmacological therapies such as remote ischemic conditioning and hypothermia are emerging. Comprehensive therapy with medication in combination with endovascular intervention and/or non-pharmacological treatment may be a potential strategy for ICAS treatment in the future. We summarized the epidemiology, pathophysiological mechanisms, risk factors, biomarkers, imaging and management of ICAS.

Percutaneous transluminal angioplasty using the novel drug-coated balloon catheter SeQuent Please NEO for the treatment of symptomatic intracranial severe stenosis: feasibility and safety study

Objectives

Intracranial arteriosclerotic disease is a relevant cause of ischemic stroke worldwide with a high recurrence rate despite best medical treatment. Following the SAMMPRIS trial, endovascular treatment has remained a second-line therapy. Meanwhile, there has been significant advances in device technology. SeQuent Please NEO is a novel polymer-free, drug-coated (paclitaxel/iopromide) balloon (DCB) primarily designed for cardiology. Because of its high flexibility and pushability, it may also be suitable for intracranial use. The aim of this study was to assess the feasibility and safety of SeQuent Please NEO DCB in symptomatic intracranial severe stenosis.

Methods

A single-center retrospective cohort study of patients with symptomatic intracranial severe stenosis treated with SeQuent Please NEO DCB was performed at a tertiary stroke center.

Results

Ten patients (all men, median age 73 years (IQR 69–77)) were included. Median pre-treatment stenosis grade was 78% (IQR 75–80%) with four internal carotid artery, two mid-basilar artery, and four vertebral artery lesions. Median post-treatment stenosis grade was 50% (IQR 45–53%). Successful angioplasty was achieved in all cases without technical failure. There were no cases of peri-procedural reocclusion and no deaths at median follow-up of 3 months (IQR 2–3).

Conclusion

In this pilot study, SeQuent Please NEO DCB was feasible and safe in the treatment of symptomatic intracranial severe stenosis. It might represent a promising alternative to medical treatment in selected cases.

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.

Balloon-expandable stents for treatment of symptomatic middle cerebral artery stenosis: Clinical outcomes during long-term follow-up

BACKGROUND

Insertion of a balloon-expandable stent (BES) in patients with symptomatic intracranial atherosclerosis is a treatment option for reperfusion therapy. In this study, we retrospectively reviewed clinical outcomes during long-term follow-up after insertion of balloon-expandable stents in patients with symptomatic middle cerebral artery (MCA) stenosis.

METHODS

Institutional review board approval was obtained for retrospective review of patient data. Thirty-four patients (15 men, 19 women; median age, 67.5 years) with symptomatic MCA stenosis underwent balloon-expandable stent insertion between June 2008 and December 2010. Patient records were reviewed for angiographic findings and clinical outcomes during long-term follow-up.

RESULTS

Of these patients, 22 presented with acute ischemic stroke with underlying MCA atherosclerosis and had good clinical outcomes (modified Rankin Scale score (mRS): 0-2) after reperfusion therapy. Indications for stenting for the remaining 12 patients were recurrent transient ischemic attacks (TIAs) refractory to medical therapy and MCA stenosis greater than 70%. During the poststenting follow-up period, which ranged from 61 to 108 months (median, 67.5 months), a TIA occurred in five patients. Of these five patients, one experienced a complete reocclusion of the MCA stent, and three had symptomatic restenosis. The remaining 29 patients did not experience any further ischemic events or restenosis during the follow-up period.

CONCLUSIONS

In our study, treatment with balloon-expandable stents in patients with symptomatic MCA stenosis resulted in low recurrence rates for both ischemic events and restenosis during long-term follow-up.

Targeting von Willebrand Factor in Ischaemic Stroke: Focus on Clinical Evidence

Despite great efforts in stroke research, disability and recurrence rates in ischaemic stroke remain unacceptably high. To address this issue, one potential target for novel therapeutics is the glycoprotein von Willebrand factor (vWF), which increases in thrombogenicity especially under high shear rates as it bridges between vascular sub-endothelial collagen and platelets. The rationale for vWF as a potential target in stroke comes from four bodies of evidence. (1) Animal models which recapitulate the pathogenesis of stroke and validate the concept of targeting vWF for stroke prevention and the use of the vWF cleavage enzyme ADAMTS13 in acute stroke treatment. (2) Extensive epidemiologic data establishing the prognostic role of vWF in the clinical setting showing that high vWF levels are associated with an increased risk of first stroke, stroke recurrence or stroke-associated mortality. As such, vWF levels may be a suitable marker for further risk stratification to potentially fine-tune current risk prediction models which are mainly based on clinical and imaging data. (3) Genetic studies showing an association between vWF levels and stroke risk on genomic levels. Finally, (4) studies of patients with primary disorders of excess or deficiency of function in the vWF axis (e.g. thrombotic thrombocytopenic purpura and von Willebrand disease, respectively) which demonstrate the crucial role of vWF in atherothrombosis. Therapeutic inhibition of VWF by novel agents appears particularly promising for secondary prevention of stroke recurrence in specific sub-groups of patients such as those suffering from large artery atherosclerosis, as designated according to the TOAST classification.

Anti-inflammatory approaches to ischaemic stroke prevention

Stroke is a major cause of neurological morbidity and mortality. Atherosclerosis is a major contributor to first and recurrent stroke. A growing evidence base indicates that inflammation is a key process in the pathogenesis of atherosclerosis, leading to thromboembolic events. In this review, we summarise the evidence linking inflammation to stroke risk and discuss clinical trials addressing the 'inflammation hypothesis' in coronary disease and stroke. Trial registration number CONVINCE trial ClinicalTrials.gov number; NCT 02898610; Pre-results.

Morphometric measurements of extracranial and intracranial atherosclerotic disease: A population-based autopsy study

BACKGROUND AND AIMS

Intracranial (IAD) and extracranial atherosclerotic diseases (EAD) have been mostly investigated using imaging methods. Autopsy studies allow for a direct and complete evaluation of the atherosclerotic disease. We aimed to investigate the frequency of IAD and EAD, their association, and related risk profiles in a large cross-sectional autopsy study.

METHODS

We measured the intima-media thickness and stenosis of the common (CCA) and internal carotid arteries (ICA), using morphometric measurements. The main outcome was stenosis (≥50%) in the artery with the largest obstruction among the 12 cerebral arteries. We used multivariable logistic regression models to investigate the association between EAD and IAD.

RESULTS

In 661 participants (mean age = 71.3 ± 11.7 y, 51% male), stenosis was more common in IAD than in EAD (59% vs. 51%). EAD was associated with Caucasian race, hypertension, and smoking, while IAD was associated with older age, less years of education, hypertension, diabetes, and a previous history of stroke. Stenosis in CCA and ICA was associated with more than two times the odds of having stenosis in the intracranial arteries (CCA: OR = 2.32, 95% CI = 1.64; 3.28; ICA: OR = 2.51, 95% CI = 1.76; 3.57).

CONCLUSIONS

In this population-based autopsy study, IAD was common, even more common than EAD, but correlated with EAD.

Angioplasty, Stenting and Other Potential Treatments of Atherosclerotic Stenosis of the Intracranial Arteries: Past, Present and Future

Although there is an intuitive appeal to treat symptomatic stenotic intracranial arteries with endovascular therapies such as angioplasty and stenting, current data from randomized trials show intensive medical therapy is far superior for preventing stroke. This is in large part due to the high risk of peri-procedural stroke from angioplasty and stenting. If angioplasty and stenting is to emerge as a proven treatment for intracranial stenosis, endovascular techniques will need to become much safer, identification of patients with intracranial stenosis who are at particularly high risk of stroke despite intensive medical therapy will need to be targeted, and well-designed randomized trials will be necessary to show endovascular therapy is superior to medical therapy in these high-risk patients.

Medical Treatment of Intracranial Atherosclerosis: An Update

For patients with symptomatic intracranial atherosclerosis (ICAS), antithrombotic agents are the mainstay of therapy. Anticoagulation (warfarin) is not widely used since it is not more effective than aspirin and carries a high risk of bleeding. New oral anticoagulants are showing promise, but their use has not been investigated in appropriate clinical trials. Since the recurrent stroke risk is high with aspirin monotherapy, dual antiplatelets are considered in the early stage of symptomatic ICAS. Based on the Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events (CHANCE) and Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) results, aspirin plus clopidogrel has been recommended. However, this combination was not superior to aspirin monotherapy in patients with ICAS in the CHANCE substudy. Progression of ICAS is common, and it is associated with recurrent strokes. In the Trial of Cilostazol in Symptomatic Intracranial Arterial Stenosis (TOSS) study, aspirin plus cilostazol was more effective than aspirin monotherapy in preventing progression. The TOSS II trial showed that the overall change in stenosis was better with aspirin plus cilostazol than with aspirin plus clopidogrel. Aside from antithrombotic therapy, risk factor management is critical for secondary prevention, and high blood pressure is clearly linked to recurrent stroke. However, blood pressure may have to be cautiously managed in the early stage of stroke. Considering that ICAS is the major cause of stroke worldwide, further investigations are needed to establish optimal management strategies for patients with ICAS.

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.

Relationship between risk factor control and vascular events in the SAMMPRIS trial

OBJECTIVE

The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) study is the first stroke prevention trial to include protocol-driven intensive management of multiple risk factors. In this prespecified analysis, we aimed to investigate the relationship between risk factor control during follow-up and outcome of patients in the medical arm of SAMMPRIS.

METHODS

Data from SAMMPRIS participants in the medical arm (n = 227) were analyzed. Risk factors were recorded at baseline, 30 days, 4 months, and then every 4 months for a mean follow-up of 32 months. For each patient, values for all risk factor measures were averaged and dichotomized as in or out of target.

RESULTS

Participants who were out of target for systolic blood pressure and physical activity, as well as those with higher mean low-density lipoprotein cholesterol and non-high-density lipoprotein, were more likely to have a recurrent vascular event (stroke, myocardial infarction, or vascular death) at 3 years compared to those who had good risk factor control. In the multivariable analysis, greater physical activity decreased the likelihood of a recurrent stroke, myocardial infarction, or vascular death (odds ratio 0.6, confidence interval 0.4-0.8).

CONCLUSIONS

Raised blood pressure, cholesterol, and physical inactivity should be aggressively treated in patients with intracranial atherosclerosis to prevent future vascular events. Physical activity, which has not received attention in stroke prevention trials, was the strongest predictor of a good outcome in the medical arm in SAMMPRIS.

CLINICALTRIALSGOV IDENTIFIER

NCT00576693.

Intracranial atherosclerosis: From anatomy to pathophysiology

Background

Intracranial atherosclerotic stenosis is an important etiology subtype of ischemic stroke. Stenosis severity was thought to be the main reference index for clinical treatment and research. However, stenosis could not reflect the ischemia risk completely, instead the hemodynamic state across the lesion, the extent of collateral circulation, and perfusion impairment downstream the stenosis are more important.

Aims

We write this review aimed to summarize novel angiographic methods applied in the evaluation of functional severity of ICAS, and commented on their limitations and prospects in future research.

Summary of review

The main methods to estimate cerebral blood flow including fractional flow assessed by signal intensity ratio, computational fluid dynamics analysis or pressure wire, quantitative magnetic resonance angiography. Fractional flow as a series cerebral hemodynamic parameters may reflect the status of collateral circulation and cerebral blood flow. But the accuracy of the methods was not validated. The method to calculate fractional flow reserve in cardiovascular disease cannot duplicate in cerebrovascular disease. Fractional flow measurement by floating a pressure guidewire across the intracranial stenosis was technically feasible and safe. In the future researches, a non-invasive method should be established to identify high-risk intracranial lesions and may help in decision-making.

Conclusions

The relationship between stenosis and cerebral blood flow was individualized. Cerebral hemodynamic criteria should be used to screen patients to endovascular treatment, which will optimize the diagnosis and treatment strategies for patients with symptomatic intracranial artery stenosis.

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.

The Design and Rationale of a Clinical Trial Evaluating Limb Postconditioning in Young Patients with Intracranial Arterial Stenosis

OBJECTIVES

To examine the effectiveness of bilateral arm remote ischemic postconditioning (RIPC) on the rehabilitation of nerve function and collateral circulation in patients with symptomatic intracranial atherosclerotic stenosis (sICAS).

SETTING

Open, controlled, prospective trial (EPIC-sICAS trial) in Xi'an, Shaanxi, China.

PARTICIPANTS

Up to 100 sICAS patients (age: 18-45 years, gender balance) who fulfill the inclusion and exclusion criteria will be enrolled and randomized to intervention group and control group (n ~ 50/group).

INTERVENTIONS

The intervention group will undergo ischemia and reperfusion on both arms twice a day for 6 months.

PRIMARY AND SECONDARY OUTCOME MEASURES

Mean changes in collateral circulation from baseline to the end of the 6-month RIPC treatment period, measured by dynamic contrast-enhanced magnetic resonance imaging, will be the primary outcome. Clinical symptoms, serum levels of vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) will be compared as secondary outcome.

RESULTS

A safety evaluation and preliminary experiment of the EPIC-sICAS trial were completed in November 2014 and March 2015, respectively. Overall and regional brain hemodynamics remained stable throughout RIPC. Activities of daily living score and serum VEGF and bFGF levels were significantly higher (P < .05) in the intervention group.

CONCLUSIONS

Repetitive bilateral arm RIPC appears to have protective effects in the brain related to angiogenesis promotion and neuroprotection in the acute phase of sICAS. Assessment of the role of RIPC in collateral circulation requires imaging tests and longer follow-up, as planned in the EPIC-sICAS trial.

Magnetic Resonance Imaging of Plaque Morphology, Burden, and Distribution in Patients With Symptomatic Middle Cerebral Artery Stenosis

Supplemental Digital Content is available in the text.

Background and Purpose—

Intracranial atherosclerosis is a major cause of ischemic stroke worldwide. Intracranial vessel wall imaging is an upcoming field of interest to assess intracranial atherosclerosis. In this study, we investigated total intracranial plaque burden in patients with symptomatic middle cerebral artery stenosis, assessed plaque morphological features, and compared features of symptomatic and asymptomatic lesions using a 3T vessel wall sequence.

Methods—

Nineteen consecutive Chinese patients with ischemic stroke and transient ischemic attack (mean age: 67 years; 7 females) with a middle cerebral artery stenosis were scanned at 3T magnetic resonance imaging; the protocol included a time-of-flight magnetic resonance angiography and the T1-weighted volumetric isotropically reconstructed turbo spin echo acquisition sequence before and after (83%) contrast administration. Chi-square tests were used to assess associations between different plaque features. Statistical significance was set at P<0.05.

Results—

Vessel wall lesions were identified in 18 patients (95%), totaling 57 lesions in 494 segments (12% of segments). Lesions were located primarily in the anterior circulation (82%). Eccentric lesions were associated with a focal thickening pattern and concentric lesions with a diffuse thickening pattern (P<0.001). When differentiating between asymptomatic and symptomatic lesions, an association (P<0.05) was found between eccentricity and asymptomatic lesions, but not for enhancement or a specific thickening pattern. Symptomatic lesions did not have any specific morphological features.

Conclusions—

Our results lead to a 2-fold conclusion: (1) The classification system of both thickening pattern and distribution of the lesion can be simplified by using distribution pattern only and (2) differentiation between symptomatic and asymptomatic atherosclerotic lesions was possible using intracranial vessel wall imaging.

Stroke due to large vessel atherosclerosis: Five new things

Purpose of review

Extracranial (EC) and intracranial (IC) large vessel atherosclerosis account for about 20% of ischemic stroke cases. In recent years, new treatments have emerged for treatment of both EC and IC disease.

Recent findings

The stroke rate in patients with carotid stenosis is decreasing with modern medical therapy. For patients with asymptomatic stenosis, the stroke rate is likely <1% per year. Some subsets of patients with symptomatic carotid disease benefit less from revascularization, and medical management can be considered in these patients. A second clinical trial has confirmed that aggressive medical management is the treatment of choice for IC atherosclerotic disease. Vessel wall imaging may be useful to define pathophysiology in patients with IC stenosis and could ultimately help tailor therapy, but further studies are needed. Medical therapy is preferred to stenting for patients with vertebral artery-origin stenosis.

Summary

Recent data and emerging concepts regarding large vessel atherosclerosis are provided.

Rigorous anaesthesia management protocol for patients with intracranial arterial stenosis: a prospective controlled-cohort study

OBJECTIVES

Reducing variability is integral in quality management. As part of the ongoing Encephaloduroarteriosynangiosis Revascularisation for Symptomatic Intracranial Arterial Stenosis (ERSIAS) trial, we developed a strict anaesthesia protocol to minimise fluctuations in patient parameters affecting cerebral perfusion. We hypothesise that this protocol reduces the intraoperative variability of targeted monitored parameters compared to standard management.

DESIGN

Prospective cohort study of patients undergoing encephaloduroarteriosynangiosis surgery versus standard neurovascular interventions. Patients with ERSIAS had strict perioperative management that included normocapnia and intentional hypertension. Control patients received regular anaesthetic standard of care. Minute-by-minute intraoperative vitals were electronically collected. Heterogeneity of variance tests were used to compare variance across groups. Mixed-model regression analysis was performed to establish the effects of treatment group on the monitored parameters.

SETTING

Tertiary care centre.

PARTICIPANTS

24 participants: 12 cases (53.8 years ± 16.7 years; 10 females) and 12 controls (51.3 years ± 15.2 years; 10 females). Adults aged 30-80 years, with transient ischaemic attack or non-disabling stroke (modified Rankin Scale <3) attributed to 70-99% intracranial stenosis of the carotid or middle cerebral artery, were considered for enrolment. Controls were matched according to age, gender and history of neurovascular intervention.

MAIN OUTCOME MEASURES

Variability of heart rate, mean arterial blood pressure (MAP), systolic blood pressure and end tidal CO2 (ETCO2) throughout surgical duration.

RESULTS

There were significant reductions in the intraoperative MAP SD (4.26 vs 10.23 mm Hg; p=0.007) and ETCO2 SD (0.94 vs 1.26 mm Hg; p=0.05) between the ERSIAS and control groups. Median MAP and ETCO2 in the ERSIAS group were higher (98 mm Hg, IQR 23 vs 75 mm Hg, IQR 15; p<0.001, and 38 mm Hg, IQR 4 vs 32 mm Hg, IQR 3; p<0.001, respectively).

CONCLUSIONS

The ERSIAS anaesthesia protocol successfully reduced intraoperative fluctuations of MAP and ETCO2. The protocol also achieved normocarbia and the intended hypertension.

TRIAL REGISTRATION NUMBER

NCT01819597; Pre-results.

Etiology of Intracranial Arterial Stenosis: Are Transcranial Color-Coded Duplex Ultrasound and 3T Black Blood MR Imaging Complementary?

BACKGROUND

In order to differentiate between the different causes of intracranial stenosis, we compared the diagnostic results of transcranial color-coded duplex (TCCD) sonography with the recently developed 3D high-resolution black blood MR sequence.

METHODS

We studied retrospectively 20 patients referred to our hospital after acute ischemic stroke who were diagnosed with intracranial stenosis and in whom a repetitive TCCD and a 3D MR T1 FAT SAT (black blood) sequence at 3T (TR/TE 350/20 ms, FOV 160×182×120 mm, 0.4×0.4×0.4 size of pixel, 300 slices, Fat Sat spair, acquisition time 6 minutes 14) were performed. Etiological diagnosis was based on one hand on the morphological aspect of the arterial wall (black blood T1 FAT SAT sequence) and on the hemodynamic aspect (TCCD) on the other hand. Analysis of black blood T1 FAT SAT MR sequence and TCCD agreement on the etiological diagnosis was performed using sign test.

RESULTS

TCCD was performed at admission and at least at two different intervals during follow-up. Eleven patients had diffuse intracranial arterial disease and nine had involvement of a single intracranial artery. Etiology of intracranial arterial stenosis included: atheromatosis, thrombosis, vasculitis and reversible vasoconstriction syndrome. There was 80% agreement (sign test P = .0059) between these two methods.

CONCLUSIONS

These two combined imaging techniques might be promising for the differentiation of arteriosclerotic changes from stenosis of another origin, especially when follow-up TCCD studies are completed early before a possible regression of the atherosclerotic plaque that might be observed 6 months after initial diagnosis.

Does the Stenting Versus Aggressive Medical Therapy Trial Support Stenting for Subgroups With Intracranial Stenosis?

BACKGROUND AND PURPOSE

Although the Stenting Versus Aggressive Medical Therapy for Intracranial Arterial Stenosis (SAMMPRIS) trial showed that medical therapy alone was superior to stenting plus medical therapy for preventing recurrent strokes in patients with symptomatic intracranial stenosis, we determined whether SAMMPRIS supported the use of stenting in any subpopulations of patients with symptomatic intracranial arterial stenosis.

METHODS

The primary outcome, 30-day stroke and death and later strokes in the territory of the qualifying artery, was compared in those with and without baseline factors in the 2 treatment arms, percutaneous transluminal angioplasty and stenting (PTAS) plus aggressive medical therapy versus aggressive medical therapy alone. Baseline factors included sex, age, race, diabetes mellitus, hypertension, lipid disorder, smoking status, type of qualifying event, qualifying event hypoperfusion symptoms, use of antithrombotic or proton pump inhibitor at baseline, days to enrollment, old infarcts in the same territory, percent stenosis, other artery stenosis, and location of the symptomatic artery.

RESULTS

A total of 451 patients were enrolled, 227 randomized to aggressive medical therapy and 224 to PTAS. Of all variables evaluated, the observed 2-year event rates were higher with PTAS than with aggressive medical therapy in the vast majority and the interaction with treatment was not statistically significant for any of the factors.

CONCLUSIONS

The SAMMPRIS results do not provide evidence to support the use of PTAS using the Wingspan stent system compared with medical treatment in any examined subpopulation of patients with symptomatic intracranial stenosis, including those with qualifying event hypoperfusion symptoms.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00576693.

Effects of cilostazol on the progression and regression of symptomatic intracranial artery stenosis: it reduces the risk of ischemic stroke

OBJECTIVE:

To assess the efficacy and safety of cilostazol on the progression and regression of symptomatic intracranial artery stenosis.

DATA RETRIVAL:

We searched the main databases for eligible trials including Medline (from 1966 to June 2014), Embase (from 1980 to June 2014), Cochrane Library (Issue 6, 2014), Chinese National Knowledge Infrastructure (from 1995 to June 2014), Current Controlled Trials (http://controlled-trials.com), Clinical Trials.gov (http://clinicaltrials.gov), and Chinese Clinical Trial Registry (http://www.chictr.org). All studies regarding prevention and treatment of symptomatic intracranial arterial stenosis by cilostazol were collected. The Mesh or text keywords were the English words: “cilostazol, phosphodiesterase 3 inhibitor, atherosclerosis, and ischemic stroke.” No restrictions were put on publications or publication language.

SELECTION CRITERIA:

Grade A or B randomized controlled trials were selected according to the quality of evaluation criteria from the Cochrane Collaboration, in which cilostazol and aspirin were used to evaluate the effects of cilostazol in the treatment of patients with symptomatic intracranial artery stenosis. The quality of study methodology was evaluated based on criteria described in Cochrane Reviewer's Handbook 5.0.1. RevMan 5.2 software was used for data analysis.

MAIN OUTCOME MEASURES:

Clinical efficacy and safety of cilostazol in stopping progression and promoting regression of symptomatic intracranial artery stenosis were measured by magnetic resonance angiography and transcranial Doppler.

RESULTS:

Two randomized controlled trials with a total of 203 patients were included in this study. The results showed that while cilostazol was associated with a significantly reduced progression of intracranial artery stenosis (OR = 0.21, 95%CI: 0.09–0.47, P < 0.01), it had no beneficial effect on symptom regression (OR = 1.42, 95%CI: 0.80–2.51, P = 0.24). During the follow-up period, although some adverse effects developed, including headache, gastrointestinal disturbance, and dizziness, incidences of bleeding were lower than in aspirin-treated patients.

CONCLUSION:

Cilostazol may prevent the progression of symptomatic intracranial artery stenosis, which could reduce the incidence of ischemic stroke.

Evaluation of flow velocity in unilateral middle cerebral artery stenosis by Transcranial Doppler

To determine the optimal velocity values in diagnosing unilateral middle cerebral artery (MCA) stenosis by Transcranial Doppler (TCD), and improve the diagnostic accuracy using magnetic resonance angiography (MRA), a total of 302 unilateral MCA stenosis patients undergoing TCD also consented to a MRA of the intracranial arteries. The peak systolic velocity (PSV) and each MCA spectrum for each patient were recorded. Using the MRA to confirm, the degree of middle cerebral artery stenosis was categorized into four groups: normal (normal caliber and signal), mild (<50 %), moderate (50-69 %), severe (70-99 %, or no flow detected). The velocity difference among these four groups was significant (P < 0.001). The optimal PSV values for normal and stenosis were 160 cm/s. For mild and moderate were 200 cm/s, for moderate and severe were 280 cm/s. Using PSV as the diagnostic criteria, the Kappa number was >0.668. The optimal PSV differential value for mild and moderate was 70 cm/s, for moderate and severe at 120 cm/s. Optimal combined criteria for moderate stenosis were PSV >200 cm/s and PSV differential value >70 cm/s (specificity 87.2 %), for severe stenosis were PSV >280 cm/s and PSV differential value >120 cm/s (sensibility 81.6 %). Transcranial Doppler distinguishes normal and MCA stenosis with a reduced lumen diameter of less than 50 %. Using the PSV criteria, TCD has a high coincidence rate with MRA in the diagnosis of MCA stenosis. Combined PSV differential value and the abnormal spectrum may improve the accuracy of TCD in diagnosing moderate or severe stenosis.

Reproducibility of Middle Cerebral Artery Stenosis Measurements by DSA: Comparison of the NASCET and WASID Methods

Purpose

To evaluate the intra- and inter-observer variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) criteria for the evaluation of middle cerebral artery (MCA) stenosis using digital subtraction angiography (DSA).

Materials and Methods

DSA images of 114 cases with 131 stenotic MCAs were retrospectively analyzed. Two radiologists and a researcher measured the degree of MCA stenosis independently using both NASCET and WASID methods. To determine intra-observer agreement, all the observers reevaluated the degree of MCA stenosis 4 weeks later. The linear relation and coefficient of variation (CV) between the measurements made by the two methods were assessed by correlation coefficient and multi-factor analysis of variance (ANOVA), respectively. Intra- and inter-observer variability of the two methods was evaluated by intraclass correlation coefficient (ICC), Spearman’s R value, Pearson correlation coefficient and Bland-Altman plots.

Results

Despite the fact that the degree of MCA stenosis measured by NASCET was lower than measured using the WASID method, there was good linear correlation between the measurements made by the two methods (for the mean measurements of the 3 observers, NASCET% = 0.891 × WASID% - 1.89%; ICC, Spearman’s R value and Pearson correlation were 0.874, 0.855, and 0.874, respectively). The CVs of both intra- and inter-observer measurements of MCA stenosis using WASID were significantly lower than that using NASCET confirmed by the multi-factor ANOVA results, which showed only the measurement methods of MCA stenosis had significant effects on the CVs both in intra- and inter-observer measurements (both P values < 0.001). Intra-observer measurements showed good or excellent agreement with respect to WASID and NASCET evaluation (ICC, 0.656 to 0.817 and 0.635 to 0.761, respectively). Good agreement for the WASID evaluation (ICC, 0.592 to 0.628) and for the NASCET evaluation (ICC, 0.529 to 0.568) was observed for inter-observer measurements. Bland-Altman plots demonstrated that the WASID method had better reproducibility and intra-observer agreement than NASCET method for evaluating MCA stenosis.

Conclusion

Both NASCET and WASID methods have an acceptable level of agreement; however, the WASID method had better reproducibility for the evaluation of MCA stenosis, and thus the WASID method may serve as a standard for measuring the degree of MCA stenosis.

Percutaneous transluminal angioplasty and stenting for severe stenosis of the intracranial extradural internal carotid artery causing transient ischemic attack or minor stroke

The purpose of this study is to assess the technical feasibility and clinical efficacy of percutaneous transluminal angioplasty and stenting (PTAS) for symptomatic stenosis of the intracranial extradural (petrous and cavernous) internal carotid artery (ICA).Review of medical records identified 26 consecutive patients who underwent PTAS using a balloon-expandable coronary stent (n = 15, 57.7%) or a Wingspan self-expandable stent (n = 11, 42.3%) for treatment of severe stenosis (>70%) involving the intracranial extradural ICA. The inclusion criteria were transient ischemic attack with an ABCD(2) score of ≥3 (n = 12, 46.2%) or minor stroke with an NIHSS score of ≤4 (n = 14, 53.8%). Technical success rates, complications, and angiographic and clinical outcomes were analyzed retrospectively.PTAS was technically successful in all patients. The mean stenosis ratio decreased from 77.1% to 10.0% immediately after PTAS. The overall incidence of procedural complications was 23.1%, and the postoperative permanent morbidity/mortality rate was 7.7%. A total of 22 patients were tracked over an average period of 29.9 months. During the observation period, 20 patients (90.9%) had no further cerebrovascular events and stroke recurrence occurred in two patients (9.1%), resulting in an annual stroke risk of 3.7%. Two cases (11.1%) of significant in-stent restenosis (>50%) were found on follow-up angiography (n = 18).PTAS for severe stenosis (>70%) involving the intracranial extradural ICA showed a good technical feasibility and favorable clinical outcome in patients with transient ischemic attack or minor stroke.

BOLD fMRI of cerebrovascular reactivity in the middle cerebral artery territory: A 100 volunteers' study

BACKGROUND AND PURPOSE

The assessment of cerebrovascular reactivity (CVR) has shown promising results for its use in medical diagnosis and prognosis, especially in patients suffering from severe intracranial arterial stenosis. However, its quantification remains uncertain because of a large variability inherent in brain anatomy and in methodological settings. To overcome this variability, we provide lateralization index (LI) values for CVR within the middle cerebral artery territory to detect CVR impairment.

MATERIALS AND METHODS

We assessed CVR in 100 volunteers (41 females; 47.52 ± 21.58 years) without cervico-encephalic arterial stenosis using BOLD-fMRI contrast with a block-design hypercapnic challenge. Averaged end-tidal CO2 was used as a physiological regressor for statistical analyses with a general linear model. We measured %BOLD signal-change in segmented gray matter regions of interest in the middle cerebral artery territory (MCA). We calculated a laterality index according to the following formula: LI=(CVRleft-CVRright)/(CVRleft+CVRright). We tested the effects of methodological settings (i.e. hypercapnic gas, gas administration means, MR acquisition and sex) on %BOLD signal change and LI values with analysis of variance.

RESULTS

No adverse effects of the hypercapnic challenge were reported. LI values were independent of experimental conditions. Mean LI calculated in MCA territories was 0.016 ± 0.031, giving the lower and upper limits of 95% (m ± 2SD) of this population distribution at]-0.05; 0.08[.

CONCLUSION

LI can effectively help us to overcome measurement variabilities. Therefore, it can be used to detect abnormal asymmetries in CVR and identify patients at higher risk of ischemic stroke.

High Blood Pressure Increases the Risk of Poor Outcome at Discharge and 12-month Follow-up in Patients with Symptomatic Intracranial Large Artery Stenosis and Occlusions: Subgroup analysis of the CICAS Study

Aims

The purpose of this study was to discuss the relationship between blood pressure and prognosis of patients with symptomatic intracranial arterial stenosis.

Methods

Data on 2426 patients with symptomatic intracranial large artery stenosis and occlusion who participated in the Chinese Intracranial Atherosclerosis (CICAS) study were analyzed. According to the JNC 7 criteria, blood pressure of all patients was classified into one of the four subgroups: normal, prehypertension, hypertension stage I, and hypertension stage II. Poor outcomes were defined as death and functional dependency (mRS 3‐5) at discharge or at 1 year.

Results

For patients with intracranial stenosis of 70% to 99%, the rate of poor outcome at discharge was 19.3%, 23.5%, 26.8%, and 39.8% (P = 0.001) for each blood pressure subgroup. For patients with intracranial large artery occlusion, the rates were 17.6%, 22.1%, 29.5%, and 49.8%, respectively (P < 0.0001). The rate of poor outcome at 12‐month follow‐up was 12.6%, 15.3%, 28.5%, and 27.9% (P = 0.0038) in patients with stenosis of 70% to 99% for each blood pressure subgroup and 11.6%, 21.5%, 23.9%, 35.1% (P < 0.0001) in patients with occlusion.

Conclusions

For patients with severe intracranial arterial stenosis or occlusion, higher hypertension stages are associated with an increased risk of poor outcome at discharge and 12‐month follow‐up.

Stroke recurrence rates among patients with symptomatic intracranial vertebrobasilar stenoses: systematic review and meta-analysis

BACKGROUND

A recent randomized trial of patients with primarily anterior circulation intracranial artery stenosis showed that intensive medical therapy was superior to intracranial stenting in preventing recurrent stroke. The rate of stroke recurrence or death in symptomatic intracranial vertebrobasilar stenosis with medical therapy alone may be especially high, and rates compared with endovascular therapy need further study.

METHODS

We conducted a systematic review and meta-analysis of studies reporting the rates of stroke recurrence or death (the primary outcome) in symptomatic intracranial vertebrobasilar stenosis with medical or endovascular treatment over a minimum follow-up period of 6 months. We included all studies in any language indexed in MEDLINE or EMBASE, supplemented by bibliography searches and by contacting the authors. The secondary endpoints were stroke recurrence, and basilar artery and vertebral artery stroke recurrence rates.

RESULTS

23 studies (592 medical treatment patients and 480 endovascular treatment patients) were included. The risk of combined stroke recurrence or death was 14.8 per 100 person-years (95% CI 9.5 to 20.1) in the medical group compared with 8.9 per 100 person-years (95% CI 6.9 to 11.0) in the endovascular group. The incidence rate ratio was 1.3 (95% CI 1.0 to 1.7). The stroke recurrence rate was 9.6 per 100 person-years (95% CI 5.1 to 14.1) in the medical group compared with 7.2 per 100 person-years (95% CI 5.5 to 9.0) in the endovascular group.

CONCLUSIONS

Our results showed that the risk of stroke recurrence or death or the risk of stroke recurrence alone was comparable between the medical and endovascular therapy groups. A small preventive effect of endovascular therapy may exist, particularly if the 30 day postprocedural risk is reduced.

Reduced CMRO₂ and cerebrovascular reserve in patients with severe intracranial arterial stenosis: a combined multiparametric qBOLD oxygenation and BOLD fMRI study

Multiparametric quantitative blood oxygenation level dependent (mqBOLD) magnetic resonance Imaging (MRI) approach allows mapping tissular oxygen saturation (StO2 ) and cerebral metabolic rate of oxygen (CMRO2 ). To identify hemodynamic alteration related to severe intracranial arterial stenosis (SIAS), functional MRI of cerebrovascular reserve (CVR BOLD fMRI) to hypercapnia has been proposed. Diffusion imaging suggests chronic low grade ischemia in patients with impaired CVR. The aim of the present study was to evaluate how oxygen parameters (StO2 and CMRO2 ), assessed with mqBOLD approach, correlate with CVR in patients (n = 12) with SIAS and without arterial occlusion. The perfusion (dynamic susceptibility contrast), oxygenation, and CVR were compared. The MRI protocol conducted at 3T lasted approximately 1 h. Regions of interest measures on maps were delineated on segmented gray matter (GM) of middle cerebral artery territories. We have shown that decreased CVR is spatially associated with decreased CMRO2 in GM of patients with SIAS. Further, the degree of ipsilateral CVR reduction was well-correlated with the amplitude of the CMRO2 deficit. The altered CMRO2 suggests the presence of a moderate ischemia explained by both a decrease in perfusion and in CVR. CVR and mqBOLD method may be helpful in the selection of patients with SIAS to advocate for medical therapy or percutaneous transluminal angioplasty-stenting.

Balloons in endovascular neurosurgery: history and current applications

The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.

Diabetes mellitus does not increase the risk of adverse long-term outcomes after intracranial stent placement

The present study is to investigate whether diabetes mellitus (DM) increases risk of adverse long-term outcomes after intracranial stent placement. Patients receiving intracranial stenting were assigned to DM group and non-DM group according to diabetes status. The long-term follow-up endpoint was composite of any stroke and death within 30 days, any ischemic stroke beyond 30 days, and transient ischemic attack in the territory of the stented artery at any time. A total of 44 stenoses in 43 patients were retrospectively analyzed. The cumulative probability of the composite outcomes were 15.4% (95% CI 15.3-47.3%) at 1 year and 30.8% (95% CI 26.5-33.6%) at 2 years for DM group; 17.5% (95% CI 16.0-31.2%) at both 1 year and 2 years for non-DM group (log-rank test, P = 0.424). After adjusting for the confounders, the risk of DM versus non-DM for composite outcomes remained insignificant (hazard ratio: 2.84, 95% CI 0.46-17.66; P = 0.26). Our results showed that there is no significant difference between patients with DM and without DM in cumulative probability of the composite outcomes. It suggests that based on our data, there is no evidence that DM increases the risk of adverse long-term outcomes after intracranial stent placement.

Natural history of intracranial atherosclerotic disease

Intracranial atherosclerotic disease was very common among stroke patients of Asians, Blacks, and Hispanics ancestry. Furthermore, stroke patients with intracranial atherosclerosis (ICAS) have higher recurrence rate of cerebral ischemia and death than those without ICAS. However, the natural history of intracranial atherosclerotic disease is still in controversy. Most of the studies were retrospective and randomized controlled trial of drugs. This review summarized the prognosis of symptomatic and asymptomatic intracranial atherosclerotic disease in order to guide clinical decision-making and further clinical research.

Routine clinical evaluation of cerebrovascular reserve capacity using carbogen in patients with intracranial stenosis

BACKGROUND AND PURPOSE

A promising method for identifying hemodynamic impairment that may serve as a biomarker for stroke risk in patients with intracranial stenosis is cerebrovascular reactivity (CVR) mapping using noninvasive MRI. Here, abilities to measure CVR safely in the clinic using hypercarbic hyperoxic (carbogen) gas challenges, which increase oxygen delivery to tissue, are investigated.

METHODS

In sequence with structural and angiographic imaging, blood oxygenation level-dependent carbogen-induced CVR scans were performed in patients with symptomatic intracranial stenosis (n=92) and control (n=10) volunteers, with a subgroup of patients (n=57) undergoing cerebral blood flow-weighted pseudocontinuous arterial spin labeling CVR. Subjects were stratified for 4 substudies to evaluate relationships between (1) carbogen and hypercarbic normoxic CVR in healthy tissue (n=10), (2) carbogen cerebral blood flow CVR and blood oxygenation level-dependent CVR in intracranial stenosis patients (n=57), (3) carbogen CVR and clinical measures of disease in patients with asymmetrical intracranial atherosclerotic (n=31) and moyamoya (n=29) disease, and (4) the CVR scan and immediate and longer-term complications (n=92).

RESULTS

Noninvasive blood oxygenation level-dependent carbogen-induced CVR values correlate with (1) lobar hypercarbic normoxic gas stimuli in healthy tissue (R=0.92; P<0.001), (2) carbogen-induced cerebral blood flow CVR in patients with intracranial stenosis (R=0.30-0.33; P<0.012), and (3) angiographic measures of disease severity both in atherosclerotic and moyamoya patients after appropriate processing. No immediate stroke-related complications were reported in response to carbogen administration; longer-term neurological events fell within the range for expected events in this patient population.

CONCLUSIONS

Carbogen-induced CVR elicited no added adverse events and provided a surrogate marker of cerebrovascular reserve consistent with intracranial vasculopathy.

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.

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.

Endovascular Advances for Intracranial Occlusive Disease

Stroke is the fourth leading cause of death in the United States. Intracranial atherosclerotic disease accounts for 8%-10% of ischemic stroke in the United States. So far, surgical bypass has not proved to be superior to medical therapy. As both medical and endovascular therapies for intracranial atherosclerosis evolve, so too do the guidelines for treatment. Initial reports on the results of stent placement for symptomatic high-grade intracranial atherosclerotic disease were encouraging; however, recent trials suggest that initial medical management may be preferable. Currently, intracranial angioplasty and stenting for symptomatic intracranial atherosclerosis is now more controversial. Further trials are necessary to help determine which patients are ideal for endovascular therapies.

Intracranial atherosclerosis: current understanding and perspectives

The importance of intracranial atherosclerotic disease (ICAD) as a cause of stroke is underscored as compared to that of extracranial carotid stenosis and nonvalvular atrial fibrillation. Recent large clinical trials of ICAD, which evaluated the effectiveness of anticoagulation and stenting to prevent thromboembolism and restore hemodynamic compromise, failed to reduce major vascular events in patients with ICAD. These trials showed the importance of optimal control of risk factors to reduce major vascular events in these patients. Recent advances in risk factors for ICAD are summarized, together with possible reasons for race-ethnic differences in the prevalence of ICAD. In addition, the failure of the major clinical trials of ICAD may be caused by limitations in the understanding of ICAD. Unlike in patients with extracranial carotid stenosis or atrial fibrillation, stroke associated with ICAD occurs in association with various stroke mechanisms such as in situ thrombotic occlusion, artery-to-artery embolism, hemodynamic insufficiency, and branch occlusion. In clinical trials of ICAD, patients with all these types of ICAD were included. However, treatment effects may differ among the different types of ICAD. Treatment strategies might be selected based on clinical features (including the time after onset) and serologic and neuroimaging biomarkers (including diffusion-weighted image pattern and plaque images). Additional clinical trials considering these features are needed.