Intracranial stenosis in Chinese patients with acute stroke

Intracranial Atherosclerosis

The most relevant ideas discussed in this article are described here. Intracranial atherosclerotic disease (ICAD) represents the most common cause of ischemic stroke worldwide. Its importance in whites may have been underestimated. New technical developments, such as high-resolution MRI, allow direct assessment of the intracranial atherosclerotic plaque, which may have a profound impact on ICAD diagnosis and therapy in the near future. Early detection of ICAD may allow therapeutic intervention while the disease is still asymptomatic. The Barcelonès Nord and Maresme Asymptomatic Intracranial Atherosclerosis Study is presented here. The main prognostic factors that characterize the patients who are at a higher risk for ICAD recurrence are classified and discussed. The best treatment for ICAD remains to be established. The Stenting Versus Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis Study is currently ongoing to address this crucial issue. These and other topics will be discussed at the Fifth International Intracranial Atherosclerosis Conference (Valladolid, Spain, autumn 2011).

Validation of the National Health Insurance Research Database with ischemic stroke cases in Taiwan

OBJECTIVE

The National Health Insurance Research Database (NHIRD) is commonly used for pharmacoepidemiological research in Taiwan. This study evaluated the validity of the database for patients with a principal diagnosis of ischemic stroke.

STUDY DESIGN AND METHODS

This cross-sectional study compares records in the NHIRD with those in one medical center. Patients hospitalized for ischemic stroke in 1999 were identified from both databases. The discharge notes, laboratory data, and medication orders during admission and the first discharge visit were reviewed to validate ischemic stroke diagnoses and aspirin prescribing in the NHIRD. Agreement between the two databases in comorbidities of ischemic stroke diagnosis was evaluated using ICD-9 codes.

RESULTS

Three hundred and seventy two cases were identified from the NHIRD; among them, 364 cases (97.85%) were confirmed as ischemic stroke by radiology examination and clinical presentation. Among these confirmed cases, 344 (94.51%) were assigned 'ischemic stroke' as the principal diagnosis in the NHIRD. The overall agreement of comorbid diagnoses between the databases was 48.39%. The PPV for selected conditions also varied widely, from 0.50 for fracture to 1.00 for colon cancer. The accuracy of recorded aspirin prescriptions was higher in first post-discharge visits (PPV = 0.94) than during hospitalization (PPV = 0.88).

CONCLUSION

The accuracy of the NHIRD in recording ischemic stroke diagnoses and aspirin prescriptions was high, and the NHIRD appears to be a valid resource for population research in ischemic stroke.

Treatment of Symptomatic Intracranial Atherosclerotic Stenosis with a Normal-Sized Gateway™ Balloon and Wingspan™ Stent

The safety and performance of angioplasty using a normal-sized Gateway™ balloon and Wingspan™ stent for intracranial atherosclerotic stenosis were assessed. Seventy-two patients with intracranial stenosis (≥ 50%) were treated using an undersized (group U) or normal-sized (group N) Gateway™ balloon and a Wingspan™ stent. All patients were successfully stented. Stenosis improved from 74.2% before treatment to 23.8% immediately after treatment in group U and from 70.9% to 20.1% in group N. The two groups had similar rates of major periprocedural neurological complications (9.0% overall), none of which led to death. Residual stenosis at follow-up was 40.8% and 32.5% in groups U and N, respectively. In-stent re-stenosis (ISR) was significantly less frequent in group N (22.0%) than in group U (33.3%). It is concluded that use of a normal-sized Gateway™ balloon and Wingspan™ stent appears to be safe, to have a high rate of technical success, good immediate post-operative results and a low ISR rate.

Stroke risk factors and outcomes among various Asian ethnic groups in Singapore

Data on interethnic differences in the Asian stroke population are limited. We evaluated the relationships among various cardiovascular risk factors, stroke subtypes, and outcomes in a multiethnic Singaporean population comprising consecutive ischemic stroke patients presenting to our tertiary center over a 1-year period. Strokes were classified based on criteria used in the Trial of Org 10172 in Acute Stroke Treatment (TOAST). Functional independence at hospital discharge was defined as a modified Rankin Scale (mRS) score of 0-2. The ethnic distribution of the study population (n = 481; mean age, 64.1 ± 11.9 years) was 74% Chinese, 17% Malay, and 9% Indian. The prevalence of risk factors was similar in the 3 ethnic groups except for diabetes (Chinese, 39.8%; Malay, 67.5%; Indian, 52.3%; P < .001). Hypertension and hypercholesterolemia were the most common cardiovascular risk factors. Lacunar stroke was the most frequent stroke subtype (47.9%). Large-artery atherosclerotic infarctions were more prevalent in Indians (25.0%), whereas lacunar infarctions occured more frequently in Chinese (51.8%; P < .01). No differences in in-hospital mortality and functional independence at discharge were seen among the 3 ethnic groups. Despite the differences in risk factors and in stroke subtypes classified by location or underlying etiology, short-term outcome measures were similar in the 3 different Asian ethnicities in Singapore.

Magnetic resonance angiography findings in patients with ischemic stroke from North India

BACKGROUND

We sought to evaluate the magnetic resonance (MR) angiography (MRA) findings in patients with ischemic stroke (IS) from North India and correlate the changes with various conventional and nonconventional risk factors.

METHODS

The study took place at a tertiary care teaching hospital. The patients with IS were clinically evaluated including body mass index, dietary habits, and family history of stroke. MR imaging, MRA, and testing for blood sugar, lipid profile, B12, folic acid, and homocysteine were carried out. The MRA abnormalities were considered significant if stenosis was 50% or greater and these were categorized into extracranial (EC), intracranial (IC), or combined lesions. The location of infarct on MR imaging was also noted.

RESULTS

There were 151 patients whose median age was 60 (22-85) years. The EC MRA was abnormal in 56.3% and the IC MRA in 63.3% of patients, the internal carotid artery being the most common site. Corresponding infarct was present in 64.7% and noncorresponding in 45.3% of patients. The MRA abnormality positively correlated with hypertension and diabetes, and negatively with alcohol consumption. The EC MRA abnormality was more common in upper caste Hindus and Muslims and in the city dwellers.

CONCLUSION

In North Indian patients with IS, the frequency of EC and IC MRA abnormality lies between Whites and the Orientals.

Ethnic differences in ischemic stroke of working age in northern Israel

BACKGROUND

There are currently no comparative data about ethnic differences in ischemic stroke in Arab and Jewish populations.

METHODS

Data on 727 consecutive Arab and Jewish patients of working age (<or=65 years) with stroke were compared for risk profile, etiology, subtyping, and immediate functional outcome.

RESULTS

The mean age was 59.4 +/- 8.2 years for the Jewish and 53.7 +/- 8.6 years for the Arab patients (P = .03). Higher prevalence of diabetes was found in the Arab patients after adjustment by age, sex, and main vascular risk factors (P < .0001). After adjustment, a higher prevalence of normal transesophageal echocardiography results in the Arab population was found. Small vessel disease-related strokes were significantly more frequent in the Arab patients, whereas large vessel disease-related strokes and strokes resulting from multiple causes were significantly more frequent in the Jewish patients. No correlations were found between the high prevalence of diabetes (or any other examined factor) and the predominance of small vessel disease-related strokes in the Arab patients and large vessel disease-related strokes in the Jewish patients. There was no difference found in treatment or outcome between the Arab and the Jewish patients.

CONCLUSIONS

There are substantial differences in the risk profiles and subtyping of strokes between Arab and Jewish patients of working age.

Comparison of BMSs with SES for symptomatic intracranial disease of the middle cerebral artery stenosis

This study was designed to compare the clinical and angiographic outcomes of patients with symptomatic atherosclerotic middle cerebral artery stenosis treated with balloon-mounted stents (BMS) and self-expandable Wingspan system (SES). We reviewed the 69 consecutive stent placement procedures for symptomatic atherosclerotic stenosis (≥70) in M1 segment of middle cerebral artery in 67 patients in 3 years. According to the stent types, the patients were classed as BMS and SES groups. The demographic characteristics, conventional risk factors of ischemic stroke, degree of stenosis, periprocedural complications, stent types, and clinical and angiographic outcomes were analyzed. There were 39 patients in the BMS group and 28 patients in the SES group. The demographic characteristics, conventional risk factors, and periprocedural complications were similar but different in residual stenosis after stenting in both groups (5.9% ± 9.9% vs. 14.4% ± 14.6%; P = 0.01). For the overall cohort, the rate of stroke or death and restenosis was 10.9% (7/66) and 24.5% (14/57), respectively. The frequency of restenosis was higher in the SES group than in the BMS group (log-rank, P = 0.04; crude hazard ratio = 3.03; 95% confidence interval (CI), 1.01-9.15; P = 0.049; and adjusted hazard ratio = 3.61; 95% CI, 1.06-12.27; P = 0.04); however, there was no difference in clinical outcomes (log-rank, P = 0.51; crude hazard ratio = 1.66; 95% CI, 0.36-7.61; P = 0.51; and adjusted hazard ratio = 0.59; 95% CI, 0.04-7.89; P = 0.69). The corrected degree of restenosis was higher in the SES than the BMS group. The prevalence of restenosis was higher in the SES than the BMS group, but the perioperative complications and follow-up clinical outcomes had no significant difference.

Increasing frequency and burden of cerebral artery atherosclerosis in Korean stroke patients

PURPOSE

Koreans have been undergoing rapid lifestyle changes that may have an effect on patterns of cerebral artery atherosclerosis. This study was aimed at determining the frequency and distribution of atherosclerosis in the cerebral arteries and associated temporal changes over the past eight-year period among Korean stroke patients.

MATERIALS AND METHODS

By using stroke registry data registered between April 1999 and March 2007, we investigated the presence, severity, and location of cerebral artery atherosclerosis as determined by angiographic findings. Their annual patterns and association with vascular risk factors were investigated.

RESULTS

Of 1,955 patients, 1,517 patients (77.6%) demonstrated atherosclerosis in one or more arteries. A significantly increasing trend of atherosclerosis was observed during the past eight years, which was ascribed to an increase of combined extracranial (EC) and intracranial (IC) atherosclerosis. The number of atherosclerotic arteries increased as the number of risk factors increased. In the multivariate analysis, the year and vascular risk factors were independent predictors of the presence of atherosclerosis.

CONCLUSION

We found that the atherosclerotic burden has been increasing for the past eight years in Korean stroke patients, particularly the combined EC and IC subtype. Lifestyle changes and increase in vascular risk factors may be contributing factors.

Epidemiology of intracranial stenosis

Intracranial stenosis is a common etiology for ischemic stroke. Due to limitations of imaging studies, there are limited data on the prevalence of symptomatic and asymptomatic intracranial stenosis. Intracranial stenosis is more prevalent in Asian, Hispanic, and African-American populations. The reported proportion of patients with symptomatic intracranial stenosis among those hospitalized for ischemic cerebral events varies from 1% in non-Hispanic whites to as high as 50% in Asian populations. In population-based studies, the estimated prevalence of symptomatic intracranial disease varies from 1 in 100,000 for whites to 15 in 100,000 in African Americans. A Chinese population-based study reported intracranial stenosis in 7% of the population aged more than 40 years. Autopsy studies have noted intracranial atherosclerotic disease in about 23% of population in the 6th decade and 80% of population in the 9th decade of life. Angiotensin-converting enzyme polymorphisms, plasma endostatin/vascular endothelial growth factor ratio, glutathione S-transferase omega-1 gene polymorphism, and plasma homocysteine levels are non-modifiable risk factors noted to be associated with intracranial stenosis. Hypertension and serum lipid profile are major modifiable risk factors, whereas sickle cell disease is an uncommon risk factor that can be managed to reduce risk. Associations of intracranial atherosclerosis with diabetes mellitus, metabolic syndrome, Alzheimer's disease, aortic plaques, radiotherapy, and meningitis are less well documented.

Intracranial angioplasty with Gateway-Wingspan system for symptomatic atherosclerotic stenosis: preliminary results of 27 Chinese patients

BACKGROUND

We investigated the safety of treatment of symptomatic intracranial atherosclerotic stenoses with the Gateway-Wingspan system and its initial effect on prevention of ischemic events.

METHODS

Twenty-seven cases of symptomatic intracranial atherosclerotic stenoses were treated with angioplasty with a Wingspan stent. Location of stenoses, extent of stenoses before and after angioplasty, success rate of treatment, occurrence of procedural complications, and changes in recurrence of symptoms of ischemic events 30 days after treatment were recorded.

RESULTS

Twenty-nine angioplasties with the Wingspan system were successfully carried out in 29 stenoses in 27 patients. Of 29 stenoses, 17 were in the posterior circulation, and 12, in the anterior circulation. The degree of stenoses was reduced from baseline 71.8% (56%-87.8%) to 24.9% (0%-45%) after stenting. Complications were seen in four patients (14.8%), 3 of which were lesion-related infarction of a perforated artery, and 1 was a non-lesion-related infarction. Two complications led to transient neurologic dysfunction, one led to defect of the visual field, and one led to hemiplegia. The prevalence of morbidity and serious morbidity were 7.4% and 3.7%, respectively, and no death occurred. No new ischemic events happened during 30 days after stenting.

CONCLUSION

Angioplasty with the Wingspan system to treat symptomatic intracranial atherosclerotic stenoses appears to be safe. Its initial effect on prevention of ischemic events is acceptable.

Intracranial atherosclerotic disease: an update

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

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

BACKGROUND AND PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

An overview of the Guangzhou biobank cohort study-cardiovascular disease subcohort (GBCS-CVD): a platform for multidisciplinary collaboration

The Guangzhou Biobank Cohort Study (GBCS, n=30 519, age >or=50 years) was established to examine the effects of genetic and environmental influences on health problems and chronic disease development. Guangzhou is undergoing massive economic development, but from a baseline that had remained unchanged for millennia. The Cardiovascular Disease Subcohort (GBCS-CVD) consists of 2000 participants who have been intensively phenotyped including a range of surrogate markers of vascular disease, including carotid artery intima-media thickness, cerebral artery stenoses, arterial stiffness, ankle-to-brachial blood pressure index and albuminuria, as well as coagulatory and inflammatory markers. Plasma and leukocytes are stored in liquid nitrogen for future studies. Preliminary demographic data show the female volunteers are younger than the male ones, but present with greater levels of adiposity including central obesity (31 vs 16%). Women had more body fat (33 vs 24%) and associated levels of adipokines. Despite this, body mass index and hip circumferences were similar, which contrasts with Caucasian populations. Men had more physician-diagnosed vascular disease (6.1 vs 2.5%), hypertension (42 vs 34%) and hyperglycaemia (36.6 vs 29.6%) than the women, but were less insulin resistant. In men, smoking (40 vs 2%) and drinking alcohol (67 vs 50%) was more common and they also had lower energy expenditures. The genotype distributions of the 15 typed single nucleotide polymorphisms were all in Hardy-Weinberg equilibrium. This article describes the rationale and methodology for the study. Given the comprehensive characterization of demographic and psychosocial determinants and biochemistry, the study provides a unique platform for multidisciplinary collaboration in a highly dynamic setting.

Computed tomography evaluation of intracranial atherosclerosis in Chinese patients with transient ischemic attack or minor ischemic stroke--its distribution and association with vascular risk factors

OBJECTIVES

Intracranial atherosclerosis has been suggested to be common in Asians. We apply a semi-quantitative CT scoring system to evaluate the degree of intracranial atherosclerotic calcification and determine its distribution, severity, and the associated risk factors. The clinical outcome of these patients after a 3-year follow-up was also evaluated.

METHODS

Sixty consecutive patients diagnosed clinically to have either a transient ischemic attack (TIA) or minor ischemic stroke and underwent early computed tomographic angiography (CTA) were included into the prospective study. Two radiologists evaluated the axial CTA images for any calcification in the precavernous, cavernous and postcavernous segments of intracranial internal carotid artery (ICA), anterior, middle, and posterior cerebral as well as vertebrobasilar arteries, based on a standard CT scoring system for extent (0-4) and thickness (0-4). The composite CT score for extent and thickness of these vascular segments or vessels were recorded for all patients. The worst site (highest composite score) was chosen as the marker of the degree of intracranial atherosclerosis of each patient. The patients were then classified into mild, moderate, and severe groups, according to a composite CT score of 0-2, 3-5, and 6-8, respectively. These findings were gathered with clinical parameters and outcome after a 3-year follow-up period and corresponding statistical analyses were conducted.

RESULTS

The most severely affected vessel was found to be intracranial internal carotid arteries, and severe, moderate, and mild atherosclerosis were present in 16 (26.67%), 30 (50%), and 14 (23.33%) patients, respectively. Using multiple logistic regression analysis, diabetes mellitus (odds ratio = 10.6, P value = .004), and age (odds ratio = 1.07, P value = .02) were found to be significant risk factors for severe intracranial atherosclerosis. Two patients in the severe group, 3 patients in the moderate group, and 1 patient in the mild group were found to have stroke or TIA after a 3-year follow-up, but there was no significant difference among the 3 groups.

CONCLUSION

Significant intracranial atherosclerosis as determined by severe CT calcification was common in a cohort of Chinese patients with TIA and minor stroke. Age and diabetes mellitus were independent significant risk factors, and this CT calcification score might serve as an early indicator of intracranial atherosclerotic disease.

MR mismatch profiles in patients with intracranial atherosclerotic stroke: a comprehensive approach comparing stroke subtypes

Most clinical trials have focused on the presence of perfusion- and diffusion-weighted imaging (PWI-DWI) mismatch by more than 20%, and different stroke subtypes were lumped together. We hypothesized that intracranial large artery atherosclerotic stroke (IC-LAA) would show different PWI-DWI and magnetic resonance angiography (MRA)-DWI mismatch profiles, compared with other stroke subtypes. Consecutive patients underwent pretreatment multiparametric magnetic resonance imaging for the acute middle cerebral artery infarcts within 6 h of symptom onset. We assessed the difference in the DWI-PWI mismatch ratio, severity of hypoperfusion, and MRA-DWI mismatch among the stroke subtypes. Of 86 patients, 19 (22.1%) had IC-LAA; 42 (48.8%) cardioembolic stroke, 15 (17.4%) extracranial-LAA, and 10 (11.6%) had cryptogenic embolic stroke. Although the volume of the penumbra was not different among the groups, the mismatch ratio was higher (P=0.003) and the severity of hypoperfusion was lower in the IC-LAA group (P=0.001). The MRA-DWI mismatch was more prevalent in the IC-LAA group than in other groups (P<0.001). Collateral grading, assessed in 41 patients, was more likely to be intermediate/excellent in the IC-LAA group (P<0.001). Multivariate testing revealed that a larger mismatch ratio and less severe hypoperfusion, and MRA-DWI mismatch were independently associated with IC-LAA. Our data show that patients with IC-LAA had different mismatch profiles, which were related to better collaterals, compared with other subtypes.

Stenting for a symptomatic posterior cerebral artery stenosis

Evolvement of endovascular devices and increase of operator expertise have made angioplasty and stenting in intracranial vessels technically possible. Stenting has been reported in treating stenosis in middle and anterior cerebral arteries with favorable outcomes. However, the feasibility of stenting for stenosis in posterior cerebral artery (PCA) has not been established. We report a patient with progressive focal cerebral ischemic symptoms, which were arrested after reconstruction of the associated PCA stenosis with stenting.

Risk factors associated with major cerebrovascular complications after intracranial stenting

BACKGROUND

There are limited data on the relationship between patient and site characteristics and clinical outcomes after intracranial stenting.

METHODS

We performed a multivariable analysis that correlated patient and site characteristics with the occurrence of the primary endpoint (any stroke or death within 30 days of stenting or stroke in the territory of the stented artery beyond 30 days) in 160 patients enrolled in this stenting registry. All patients presented with an ischemic stroke, TIA, or other cerebral ischemic event (e.g., vertebrobasilar insufficiency) in the territory of a suspected 50-99% stenosis of a major intracranial artery while on antithrombotic therapy.

RESULTS

Cerebral angiography confirmed that 99% (158/160) of patients had a 50-99% stenosis. In multivariable analysis, the primary endpoint was associated with posterior circulation stenosis (vs anterior circulation) (hazard ratio [HR] 3.4, 95% confidence interval [CI] 1.2-9.3, p = 0.018), stenting at low enrollment sites (< 10 patients each) (vs high enrollment site) (HR 2.8, 95% CI 1.1-7.6, p = 0.038), < or = 10 days from qualifying event to stenting (vs > or = 10 days) (HR 2.7, 95% CI 1.0-7.8, p = 0.058), and stroke as a qualifying event (vs TIA/other) (HR 3.2, 95% CI 0.9-11.2, p = 0.064). There was no significant difference in the primary endpoint based on age, gender, race, or percent stenosis (50-69% vs 70-99%).

CONCLUSIONS

Major cerebrovascular complications after intracranial stenting may be associated with posterior circulation stenosis, low volume sites, stenting soon after a qualifying event, and stroke as the qualifying event. These factors will need to be monitored in future trials of intracranial stenting.

Intracranial atherosclerotic disease; current options for surgical or medical treatment

Recently, intracranial atherosclerosis has become a major cause of ischemic stroke, appearing more frequently in Koreans than Caucasians. Symptomatic or asymptomatic intracranial atherosclerosis is a disease that could recur readily even during the treatment with anti-platelet agents. When the symptoms develop, ischemic stroke can not be recovered readily. Therefore, aggressive treatments such as endovascular therapy and bypass surgery are required in addition to medical treatment for the intracranial artery stenosis. Recent intracranial stenting and drug eluting stenting have shown as very advanced effective therapeutic modalities. Nevertheless, until now, a randomized controlled study has not been conducted. Regarding bypass surgery, since the failed EC-IC bypass surgery study performed 20 years ago, extensive studies on its efficacy has not been conducted yet, and thus it has to be performed strictly only in hemodynamically compromised patients. Unless breakthrough drugs that suppress the progression of intracranial atherosclerosis and the formation of thrombi, and facilitate the regression of the arterial stenosis, the treatment concept of the recovery of the blood flow of stenotic arterial territory by mechanical recanalization or bypass surgery would be remained for the prevention as well as treatment of ischemic stroke caused by intracranial atherosclerosis.

[Intracranial atherosclerosis]

Until recently, intracranial atheromatosis was a probably underdiagnosed clinicopathological entity that was rarely studied in depth. In the last years the advance and expansion in the use of non-invasive diagnostic tools have led intracranial atheromatosis to the front page among the most prevalent causes of stroke worldwide. Important efforts have been accomplished with the aim of identifying markers of poor outcome, which, besides the underlying mechanisms of cerebral ischemia in these patients, are the most important factors on which clinical and therapeutic decisions should be based. To date, the therapeutic armamentarium is scarce and far from optimun, regarding medical and endovascular measures. In this review we address the most important aspects of the natural history and cure treatment of intracranial atheromatosis.

Management of patients with symptomatic intracranial atherosclerosis

Intracranial atherosclerosis is a common cause of stroke, accounting for about 50% of ischaemic stroke in Asia and 8% in North America. Many prospective studies have confirmed that intracranial stenosis is an independent predictor for poor outcomes such as recurrent vascular event and death, despite the use of antiplatelet agents. The annual event rate is about 15% per year. The dismal outcome prompts the study of more aggressive treatment strategies, including warfarin and endovascular intervention. We have reviewed the published literature for the treatment of symptomatic intracranial stenosis. The Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial and Warfarin-Aspirin Recurrent Stroke Study (WARSS) studies failed to show that oral anticoagulation was better than aspirin in IAS. Initial encouraging results were found in the use of dual antiplatelet therapy in arresting the progression of stenosis. The results of the endovascular studies are mixed: there are more encouraging results with recent advances of technology in stent design, but a randomized controlled study is still lacking. Although there is still no established therapy for IAS, the results of ongoing randomized clinical trials to study dual antiplatelet agents and the use of endovascular intervention may soon provide clinicians with more evidence to better manage patients with this condition.

Intravascular ultrasound of symptomatic intracranial stenosis demonstrates atherosclerotic plaque with intraplaque hemorrhage: a case report

BACKGROUND

Intracranial artery stenosis is assumed to represent atherosclerotic plaque. Catheter cerebral arteriography shows that intracranial stenosis may progress, regress, or remain unchanged. It is counterintuitive that atherosclerotic plaque should spontaneously regress, raising questions about the composition of intracranial stenoses. Little is known about this disease entity in vivo. We provide the first demonstration of in vivo atherosclerotic plaque with intraplaque hemorrhage using intravascular ultrasound (IVUS).

CASE DESCRIPTION

A 35-year-old man with multiple vascular risk factors presented with recurrent stroke failing medical therapy. Imaging demonstrated left internal carotid artery occlusion, severe intracranial right internal carotid artery stenosis, and cerebral perfusion failure. Cerebral arteriography with IVUS confirmed 85% stenosis of the petrous right carotid artery due to atherosclerotic plaque with intraplaque hemorrhage. Intracranial stent-supported angioplasty was performed with IRB approval. The patient recovered without complication.

CONCLUSIONS

This case supports the premise that symptomatic intracranial stenosis can be caused by atherosclerotic plaque complicated by intraplaque hemorrhage similar to coronary artery plaque. IVUS provides additional characteristics that define intracranial atherosclerosis and high-risk features. To our knowledge, this is the first report of stroke due to unstable atherosclerotic plaque with intraplaque hemorrhage in vivo.

How Accurate Is CT Angiography in Evaluating Intracranial Atherosclerotic Disease?

Background and Purpose— Digital subtraction angiography (DSA) is regarded as the gold standard in assessing degree of stenosis in intracranial vessels. However, it is invasive and can only be carried out at specialized centers. We sought to compare CT angiography (CTA) to DSA for detection and measurement of stenosis in large intracranial arteries.

Methods— -We identified all subjects admitted with ischemic stroke or transient ischemic attack and with CTA and DSA studies of good quality completed within 30 days of each other between April 2000 and May 2006 at a single medical center. Two readers blinded to clinical information reviewed each CTA and DSA independently. Each reader located and measured stenosis of 15 prespecified large intracranial arterial segments per study at the same level of magnification. These stenotic lesions were most likely atherosclerotic in etiology. All measurements were made with Wiha digiMax 6“ digital calipers. The degree of stenosis was calculated using the published method for the Warfarin-Aspirin Symptomatic Intracranial Disease study. All disagreements of greater than 10% were reviewed by a third reader who decided between the 2 prior measurements. Segments were excluded from analyses if they were judged to be congenitally hypoplastic or seen only through collaterals or cross-filling. Intraclass correlation, sensitivity, and specificity were calculated using DSA as the reference standard.

Results— Forty-one pairs of CTA and DSAs from 41 patients were reviewed. CTAs were completed within 28 days before 13 days after DSA, with a median of 1 day. A total of 475 pairs of major intracranial arterial segment were analyzed. Intraclass correlation between degree of stenosis based on CTA and DSA for all segments was 0.98 ( P =0.001). CTA detected large arterial occlusion with 100% sensitivity and specificity. For detection of ≥50% stenosis, CTA had 97.1% sensitivity and 99.5% specificity. To detect all lesions ≥50% as determined by DSA, the cut off point on CTA appeared to be at ≥30%, with a false-positive rate of 2.4%.

Conclusions— Compared to DSA, CTA has high sensitivity and specificity for detecting ≥50% stenosis of large intracranial arterial segments. CTA is minimally invasive and may be a useful screening tool for intracranial arterial disease and occlusion.

Progression of symptomatic intracranial large artery atherosclerosis is associated with a proinflammatory state and impaired fibrinolysis

BACKGROUND AND PURPOSE

The molecular pathways involved in the progression of intracranial large artery atherosclerosis (ILA) are largely unknown. Our objective was to prospectively study the relationship between circulating levels of inflammatory markers and fibrinolysis inhibitors, and the risk of progression of symptomatic ILA.

METHODS

Seventy-five consecutive patients with first-ever symptomatic intracranial atherostenosis were studied. Blood levels of C-reactive protein (CRP), E-selectin, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, matrix metalloproteinases 1, 2, 3, 8, 9, 10, and 13, plasminogen activator inhibitor-1 (PAI-1), and lipoprotein(a) were measured 3 months after the qualifying stroke or transient ischemic attack. Thereafter, patients underwent long-term transcranial Doppler follow-up to detect progression of ILA.

RESULTS

During a median follow-up time of 23 months, 25 (33%) patients showed ILA progression. Multivariable adjusted Cox regression models and Kaplan-Meier curves showed that high baseline level of CRP, E-selectin, intercellular adhesion molecule-1, matrix metalloproteinase 9, PAI-1, and lipoprotein(a) predicted ILA progression independently of vascular risk factors. Of them, only CRP (CRP>5.5 mg/L; HR, 5.4 [2.3 to 12.7]; P=0.0001) and PAI-1 (PAI-1>23.1 ng/mL; HR, 2.4 [1.0 to 5.8]; P=0.05) predicted ILA progression also independently of the other studied molecules.

CONCLUSIONS

Progression of symptomatic ILA is associated with a proinflammatory state, as reflected by high levels of inflammatory markers, and with defective fibrinolysis, as indicated by raised concentrations of endogenous fibrinolysis inhibitors.

Prevalence and prognosis of coexistent asymptomatic intracranial stenosis

BACKGROUND AND PURPOSE

There are limited data on the prevalence and prognosis of asymptomatic intracranial stenosis (AIS).

METHODS

Baseline cerebral angiograms and MR angiograms were used to determine AIS (50% to 99%) coexistent to symptomatic intracranial stenosis for patients enrolled in the Warfarin-Aspirin Symptomatic Intracranial Disease study.

RESULTS

Coexisting AIS were detected in 18.9% (n=14/74) of patients undergoing 4-vessel cerebral angiography and 27.3% (n=65/238) of patients undergoing MR angiogram. During a mean follow-up period of 1.8 years, no ischemic strokes were attributable to an AIS on cerebral angiography and 5 ischemic strokes (5.9%, 95% CI: 2.1% to 12.3%) occurred in the AIS territory on MR angiogram (risk at 1 year=3.5%, 95% CI: 0.8% to 9.0%).

CONCLUSIONS

Whereas the prevalence of coexisting AIS (50% to 99%) in patients with symptomatic stenosis is high, the risk of stroke from these asymptomatic stenoses is low.

The NIH registry on use of the Wingspan stent for symptomatic 70-99% intracranial arterial stenosis

BACKGROUND

The Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial showed that patients with symptomatic 70% to 99% intracranial arterial stenosis are at particularly high risk of ipsilateral stroke on medical therapy: 18% at 1 year (95% CI = 3% to 24%). The Wingspan intracranial stent is another therapeutic option but there are limited data on the technical success of stenting and outcome of patients with 70% to 99% stenosis treated with a Wingspan stent.

METHODS

Sixteen medical centers enrolled consecutive patients treated with a Wingspan stent in this registry between November 2005 and October 2006. Data on stenting indication, severity of stenosis, technical success (stent placement across the target lesion with <50% residual stenosis), follow-up angiography, and outcome were collected.

RESULTS

A total of 129 patients with symptomatic 70% to 99% intracranial stenosis were enrolled. The technical success rate was 96.7%. The mean pre and post-stent stenoses were 82% and 20%. The frequency of any stroke, intracerebral hemorrhage, or death within 30 days or ipsilateral stroke beyond 30 days was 14.0% at 6 months (95% CI = 8.7% to 22.1%). The frequency of >or=50% restenosis on follow-up angiography was 13/52 (25%).

CONCLUSION

The use of a Wingspan stent in patients with severe intracranial stenosis is relatively safe with high rate of technical success with moderately high rate of restenosis. Comparison of the event rates in high-risk patients in Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) vs this registry do not rule out either that stenting could be associated with a substantial relative risk reduction (e.g., 50%) or has no advantage compared with medical therapy. A randomized trial comparing stenting with medical therapy is needed.

Prevalence and Risk Factors of Middle Cerebral Artery Stenosis in Asymptomatic Residents in Rongqi County, Guangdong

BACKGROUND

Intracranial atherosclerosis is the commonest vascular lesion for ischemic stroke in Asians. Most research on risk factors for middle cerebral artery (MCA) stenosis has been conducted in symptomatic patients with ischemic stroke or transient ischemic attack. The present study aimed to investigate risk factors for MCA stenosis in an asymptomatic population in Rongqi County in Southern China.

METHODS

We assessed 1,068 asymptomatic subjects over 50 years of age by transcranial Doppler. Medical history documentation and investigation of biochemical markers were performed for each subject. Multivariant, unconditioned, logistic regression analyses were employed to assess the risk factors associated with MCA stenosis.

RESULTS

MCA stenosis was found in 63 subjects (5.9%). Male gender, advancing age, hypertension, diabetes and systolic blood pressure were significant risk factors for MCA stenosis (p < 0.001). Based on logistic regression analyses, 4 factors emerged as independent risk factors (p < 0.001) of MCA stenosis: male gender [95% confidence interval (CI) = 1.49-4.66, OR = 2.63], age (95% CI = 1.01-1.06, OR = 1.04), hypertension (95% CI = 4.57-18.35, OR = 9.16) and diabetes mellitus (95% CI = 3.09-11.29, OR = 5.9).

CONCLUSION

MCA stenosis is relatively common among asymptomatic Chinese subjects. Male gender, advanced age, hypertension and diabetes mellitus are risk factors for MCA stenosis.

Low-molecular-weight heparin compared with aspirin for the treatment of acute ischaemic stroke in Asian patients with large artery occlusive disease: a randomised study

BACKGROUND

Acute stroke patients with large artery occlusive disease (LAOD) have a distinct pathophysiology and may respond differently to anticoagulation treatments. We compared the efficacy of a low-molecular-weight heparin (LMWH), nadroparin calcium, with aspirin in Asian acute stroke patients with LAOD.

METHODS

Acute ischaemic stroke patients with onset of symptoms less than 48 h and LAOD (diagnosed by transcranial doppler imaging, carotid duplex scan, or magnetic resonance angiography) were recruited. Patients were randomly assigned to receive either subcutaneous nadroparin calcium 3800 anti-factor Xa IU/0.4 mL twice daily or oral aspirin 160 mg daily for 10 days, and then all received aspirin 80-300 mg once daily for 6 months. This study is registered at www.strokecenter.org/trials (number 493).

FINDINGS

Among 603 patients recruited, 353 (180 LMWH, 173 aspirin) had LAOD (300 had intracranial LAOD only, 42 had both intracranial and extracranial disease, and 11 had extracranial disease only). The proportion of patients with good outcomes at 6 months (Barthel index >or=85) was 73% in the LMWH group and 69% in the aspirin group (absolute risk reduction 4%; 95% CI -5 to 13). Analysis of prespecified secondary outcome measures showed a benefit in outcome for LMWH versus aspirin on the modified Rankin scale dichotomised at 0-1 (odds ratio 1.55, 95% CI 1.02-2.35). Haemorrhagic transformation of infarct and severe adverse events were similar in both groups. Post-hoc analyses of patients without LAOD, and all treated patients, showed similar proportions with a good outcome in aspirin and LMWH groups (78%vs 79% and 73%vs 75%, respectively).

INTERPRETATION

Overall, the results do not support a significant benefit of LMWH over aspirin in patients with LAOD. The benefits indicated in most outcome measures warrant further investigation into the use of anticoagulation for acute stroke in patients with large artery atherosclerosis, particularly in intracranial atherosclerosis.

Management of symptomatic intracranial atherosclerotic disease

Recently completed prospective studies have shown that with an incidence of recurrent stroke of approximately 10% per year, significant mortality, and other vascular comorbidities, symptomatic intracranial stenosis is a marker of aggressive vascular disease. Although strict control of atherosclerotic risk factors and antithrombotic therapy preferably with antiplatelet agents should be the mainstay of treatment for every patient with this disease, some patients are likely to remain refractory to medical therapy. These high-risk patients appear to be individuals with recent symptoms and severe (> 70%) stenosis with clinical and imaging evidence of hemodynamic impairment distal to the stenotic artery. Advances in balloon and stent technology have made consideration of these high-risk patients for endovascular management with angioplasty and stenting possible, which should ideally take place as part of randomized clinical trials, because the benefit of these high-risk therapies compared with medical therapy is not yet established. This article reviews available medical treatment options for symptomatic intracranial disease and outlines the current state of endovascular therapy for this disease.

Hyperhomocysteinemia is a risk factor of middle cerebral artery stenosis

PURPOSE

Hyperhomocysteinemia (HHcy) is considered to be an independent risk factor for atherosclerosis. We aimed to determine the relation between Hcy and cerebral artery stenosis in a large Chinese population.

METHODS

We present data concerning 2,500 residents. Plasma was saved from 1,020 residents who were asymptomatic. Hcy concentration was measured by fluorescence ration biochemical assay kit, and middle cerebral artery (MCA) was assessed by Transcranial Doppler in these subjects.

RESULTS

Fifty-six residents with MCA stenosis were included in this study. The remained 964 residents without stenosis were control. Analysis of the data revealed that the plasma concentration of Hcy (18.33+/-5.34 micromol/L), age (63.9+/-12.9) and systolic pressure (142.6+/-22.6 mmHg) in the stenotic group were increased (p<0.0001) compared with the control group (Hcy12.95+/-4.57 micromol/L, age 55.8+/-10.9, systolic pressure 126.3+/-20.3 mmHg). Based on logistic regression, 5 factors emerged as independent predictors of MCA stenosis: Hcy (OR=1.16, 95%confidence interval 1.14-1.26), male (OR=2.63, 95%CI 1.49-4.66), age (OR=1.04, 95%CI 1.01-1.07), hypertension (OR=9.16, 95%CI 4.57-18.35), diabetes mellitus (OR=5.90, 95%CI 3.09-11.29).

CONCLUSION

Hyperhomocysteinemia might be one of the risk factors for cerebral artery stenosis. It may play a role in atherosclerosis and thrombosis.

Carotid Ultrasound Criteria for Detecting Intracranial Carotid Stenosis

BACKGROUND/AIMS

This study attempted to establish carotid ultrasound criteria for identifying stenosis of the intracranial internal carotid artery (ICA) and middle cerebral artery (MCA).

METHODS

Two hundred and fifty-five patients were enrolled. Ultrasound measurements for common carotid artery (CCA) and ICA were as follows: flow volume (FV), peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI) and resistance index (RI). The sensitivity and specificity of the ultrasound criteria for determining intracranial ICA or MCA>or=50% stenosis were calculated.

RESULTS

The criteria identified for detecting intracranial ICA>or=50% stenosis were ICA FV<159 ml/min, ICA PSV<33 cm/s and CCA PSV<42 cm/s. When ICA PSV<33 cm/s was combined with CCA PSV<42 cm/s, sensitivity increased to 82%, with 91% specificity. The criteria identified for detecting MCA>or=50% stenosis were CCA FV<285 ml/min, ICA FV<179 ml/min, ICA PSV<33 cm/s, >35% reduction in FV in the CCA, >40% reduction in FV in ICA, and >35% reduction in PSV in ICA. When these criteria were combined, sensitivity increased to 69%, with 85% specificity.

CONCLUSION

This study demonstrated that ultrasound criteria are sensitive and specific for detecting intracranial ICA and MCA significant obstruction.

Statistical parametric mapping and statistical probabilistic anatomical mapping analyses of basal/acetazolamide Tc-99m ECD brain SPECT for efficacy assessment of endovascular stent placement for middle cerebral artery stenosis

INTRODUCTION

Statistical parametric mapping (SPM) and statistical probabilistic anatomical mapping (SPAM) were applied to basal/acetazolamide Tc-99m ECD brain perfusion SPECT images in patients with middle cerebral artery (MCA) stenosis to assess the efficacy of endovascular stenting of the MCA.

METHODS

Enrolled in the study were 11 patients (8 men and 3 women, mean age 54.2 +/- 6.2 years) who had undergone endovascular stent placement for MCA stenosis. Using SPM and SPAM analyses, we compared the number of significant voxels and cerebral counts in basal and acetazolamide SPECT images before and after stenting, and assessed the perfusion changes and cerebral vascular reserve index (CVRI).

RESULTS

The numbers of hypoperfusion voxels in SPECT images were decreased from 10,083 +/- 8,326 to 4,531 +/- 5,091 in basal images (P = 0.0317) and from 13,398 +/- 14,222 to 7,699 +/- 10,199 in acetazolamide images (P = 0.0142) after MCA stenting. On SPAM analysis, the increases in cerebral counts were significant in acetazolamide images (90.9 +/- 2.2 to 93.5 +/- 2.3, P = 0.0098) but not in basal images (91 +/- 2.7 to 92 +/- 2.6, P = 0.1602). The CVRI also showed a statistically significant increase from before stenting (median 0.32; 95% CI -2.19-2.37) to after stenting (median 1.59; 95% CI -0.85-4.16; P = 0.0068).

CONCLUSION

This study revealed the usefulness of voxel-based analysis of basal/acetazolamide brain perfusion SPECT after MCA stent placement. This study showed that SPM and SPAM analyses of basal/acetazolamide Tc-99m brain SPECT could be used to evaluate the short-term hemodynamic efficacy of successful MCA stent placement.

Endovaskuläre Behandlung intrakranieller Stenosen

Intracranial stenoses cause 5-10% of all strokes and are increasingly detected by means of modern imaging methods. The stroke danger of high-grade symptomatic stenoses is relatively high, with an annual risk of approximately 10% under medical treatment. Coumadin increases the risk of hemorrhage, and after risk/benefit considerations, antiplatelets should be preferred for antithrombotic therapy. Despite optimized medical treatment, a small group of patients with recurrent symptoms or symptomatic stenoses without adequate collateral supply probably carry higher spontaneous stroke risk and may be considered for intracranial stenting, which itself is associated with procedural risks of up to 10%. Currently published case series show relatively high complication rates as a major drawback of endovascular treatment, mainly strokes after occlusion of perforating branches extending from the stenotic vessel segment or hemorrhagic complications. According to data from smaller feasibility studies, stroke rates in follow-up after successful stenting seem to be low. The average rate of high-grade restenosis with possible indication for reintervention is 10%. Improvements in endovascular treatment aim at reducing vessel wall trauma during balloon angioplasty by underdilatation or the use of self-expanding stents. Until complication rates are dependably reduced to values of 5-6%, indication for endovascular treatment should be restricted to patients without therapeutic alternatives. According to limited data with large variation between different studies, a prospective multicentric registry is proposed for systematic evaluation and further development of the method.

Intracranial atherosclerotic stroke: specific focus on the metabolic syndrome and inflammation

Stroke is the second leading cause of mortality world-wide and is well suited for prevention because it has a high prevalence, high burden of economic cost, well-defined modifiable risk factors, and effective prevention measures. Atherosclerosis is one of the major mechanisms of ischemic stroke, but the apparent differences in risk factors for intra- and extracranial atherosclerosis are unclear and the mechanisms that underlie strokes in patients with intracranial atherosclerosis are not well known. Consequently, patients with intracranial stenosis receive the same treatment as those with carotid -atherosclerosis. Several novel substances have emerged recently as risk factors for atherosclerosis. Specifically, it has recently been suggested that both the metabolic syndrome, which refers to a constellation of metabolic risk factors that are linked to insulin resistance, and vascular inflammation are associated with increased risk of coronary heart disease and stroke. The results of the studies reviewed here suggest that these factors play a differential role in the development of atherosclerotic stroke between the intra- and extracranial arterial systems.