Asymptomatic Intracranial Stenosis Research Articles

Prognostic value of mild asymptomatic intracranial atherosclerosis stenosis in patients with hypertension.

Mild asymptomatic intracranial atherosclerotic stenosis (aICAS) is common in Chinese patients with hypertension. However, there are no data on its prognostic value in this population. The aim of the present study was to clarify the prevalence and associated cardiovascular risk factors of mild aICAS and determine its prognostic value for overall and cardiovascular mortality in patients with hypertension. In total, 1813 participants were evaluated for aICAS using computed tomographic angiography. The predictive effect of mild to severe aICAS on all-cause and cardiovascular mortality was evaluated using Kaplan-Meier survival curves and Cox regression analyses. The prevalence rate of mild aICAS was 35.7%. Poorly controlled hypertension, in combination with diabetes and dyslipidemia, was associated with aICAS. Patients with aICAS had an independently significant increase in the risk of all-cause and cardiovascular death, with adjusted hazard ratios (HRs) for mild to severe stenosis ranging from 1.52 to 3.03 for all-cause death and from 2.48 to 6.38 for cardiovascular death. Among the patients with mild aICAS, only those with more than two stenoses had increased mortality after adjustment, with an HR of 2.35 (95% CI: 1.36-4.04) for total death and 4.41 (95% CI: 1.78-10.93) for cardiovascular death. A significant association between mild aICAS and mortality in stroke-free patients with hypertension was revealed. The results indicate that mild aICAS might be an imaging marker for cerebrovascular lesions in patients with hypertension and poor control of blood pressure and lipids in this population requires further research.

Progressive Lacunar Strokes: A Predictive Score

Background and PurposeProgressive lacunar syndromes (PLS) occur in up to 20-30% of patients with lacunar strokes, increasing the risk of long term dependency. Our aim is to develop a predictive score to identify patients at high risk of presenting PLS. MethodsWe derived a risk score for PLS in a cohort of consecutive patients (n=187) presenting with one of the five classic lacunar syndromes (LS) and absence of vascular occlusion, perfusion deficit or symptomatic stenosis. A risk score was developed using the coefficients from the logistic regression model, and receiver operating characteristic (ROC) analysis was conducted to assess the prognostic value of the risk score. Sensitivity, specificity and accuracy were estimated for each total point score. ResultsOut of 187 patients included in our sample, 52 (27.8%) presented PLS. Previous history of diabetes mellitus (1 point), diastolic blood pressure at admission (2 points), clinical deficits consistent with a pure motor syndrome (1 point) and asymptomatic intracranial atheromatosis or stenosis in non-symptomatic territory (1 point) were independent predictors for PLS. The estimated area under the ROC curve for this model was 0.77 (95% CI,0.68 - 0.84). ConclusionThis score could be a useful tool in routine clinical practice to predict the occurrence of PLS, allowing the identification of those patients with LS who are at high risk of long term dependency due to early neurological worsening, and who would benefit the most from an intensive treatment.

Impact of Type 2 Diabetes Mellitus on the Cerebral Blood Vessels in Asymptomatic Patients in Egypt (Ultrasonographic Study)

Background: Diabetes is an important risk factor of extra and intracranial stenosis and hence can cause cerebrovascular stroke. In Egypt, prevalence of asymptomatic extra and intracranial blood vessels stenosis in diabetic patients is still unknown. Objectives: To estimate the prevalence of asymptomatic extra and intracranial vessels stenosis. Methods: 100 Patients with Type-2 Diabetes (T2D) were recruited consecutively from diabetes clinic of the department of internal medicine at Assiut University Hospitals in the period from 1st January 2016 to 31st January 2017. A detailed history was obtained for all participant. As well, thorough-out physical and neurologic examination were carried out for patients. All patients underwent extra cranial and transcranial colour coded ultrasound by two independent investigators. Patients with history of cerebrovascular stroke and transient ischemic attacks were excluded. Results: 36% of patients had increased IMT, 6% had stenosis 50-69% and 2% had stenosis ≥ 70%. There was a positive correlation between age and increased IMT (r = 0.272) (P = 0.006) and between uncontrolled DM and increased IMT (r = 0.211) (P = 0.035). 26% of patients had stenosis of < 50% in vertebral artery (21% in V0 segment, 5% in V1 segment); being male and uncontrolled diabetes escalate the stenosis risk. MCA pulsatility index was found to be higher among old diabetics in comparison to younger diabetics and control group (r = -0.225) (P = -0.025). Also, the longer the time since T2D onset, the higher was MCA PSV (r = 0.244) (P = 0.014). Conclusions: The cerebral blood vessels atherosclerotic changes (mainly extracranial) are higher among diabetics in comparison to healthy controls.

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

Asymptomatic intracranial stenosis (ICS) is a frequent finding on imaging results, particularly in the assessment of acute stroke. Although the management of symptomatic ICS is informed by randomized trials, to our knowledge there are few data on the prevalence and prognosis of asymptomatic ICS in patients with stroke and transient ischemic attack (TIA). To study the age-specific prevalence and prognosis of asymptomatic ICS in a population-based cohort of patients with TIA and minor stroke. All patients (predominantly white) recruited to the Oxford Vascular Study (Oxfordshire, England) between March 1, 2011, and March 1, 2018, with TIA and minor ischemic stroke (National Institutes of Health Stroke Scale score, ≤3), irrespective of age, were included (n = 1579). We determined the age-specific prevalence of 50% or more asymptomatic ICS and the associated stroke risk by face-to-face follow-up to 2018 on standard medical treatment without stenting. Patients underwent magnetic resonance angiography of the intracranial and cervicocranial arteries, computed tomography angiography if magnetic resonance angiography was contraindicated, or carotid/transcranial Doppler ultrasonography if computed tomography angiography was contraindicated. The primary outcomes were the prevalence and prognosis of asymptomatic ICS. Of 1368 eligible patients (mean [SD] age, 69.2 [13.9] years; 700 men [51.2%]) with intracranial vascular imaging, 426 ICS were identified in 260 patients (19.0%): 58 (4.2%) with only symptomatic ICS, 155 (11.3%) with only asymptomatic ICS, and 47 (3.4%) with both. The prevalence of any asymptomatic ICS increased from 4.8% for patients younger than 70 years to 34.6% for patients 90 years or older (P for trend < .001; odds ratio per decade, 1.96; 95% CI, 1.69-2.27) and was greater than that of 50% or more asymptomatic carotid bifurcation stenosis (202 [14.8%] vs 105 patients [7.2%]; relative risk, 2.04; 95% CI, 1.63-2.55, P < .001). However, the 155 patients with only asymptomatic ICS had no increase in risk of ischemic stroke compared with those with no ICS (unadjusted HR, 1.03, 95% CI, 0.49-2.17), with 8 first recurrent events (5.2%) during 506 patient-years of follow-up and 3 in the territory of the ICS (annualized risk, 0.59%; 95% CI, 0.12-1.73). The prevalence of asymptomatic ICS increases with age in white patients with TIA and minor stroke and is greater than that of asymptomatic carotid stenosis, but asymptomatic ICS does not increase the short- or medium-term risk of distal recurrent ischemic stroke for patients receiving standard medical treatment.

Prevalence, predictors, and prognosis of symptomatic intracranial stenosis in patients with transient ischaemic attack or minor stroke: a population-based cohort study.

SummaryBackgroundSymptomatic intracranial stenosis was perceived to convey a high risk of recurrent stroke, but two previous trials (SAMMPRIS and VISSIT) did not show superiority of intracranial stenosis stenting over intensive medical management alone. These findings were partly due to a lower than expected risk of recurrent stroke without stenting, possibly reflecting the young age of recruits (median age <60 years), and raise questions about generalisability to routine clinical practice. We therefore studied the age-specific prevalence, predictors, and prognosis of symptomatic intracranial stenosis in a population-based cohort of patients with transient ischaemic attack and minor stroke on intensive medical management.MethodsThe Oxford Vascular Study (OXVASC) is a prospective incidence cohort study of all vascular events in a population of 92 728 people residing in Oxfordshire, UK. All patients, irrespective of age, with transient ischaemic attack and minor ischaemic stroke occurring between March 1, 2011, and March 1, 2018 (follow-up to Sept 28, 2018), were ascertained with multiple methods, including assessment in a dedicated daily emergency clinic and daily review of all hospital admissions. Imaging was by MR angiography of the intracranial and cervicocranial arteries, by CT angiography if MR angiography was contraindicated, and by transcranial Doppler and carotid ultrasound if CT angiography was contraindicated. All patients received intensive medical treatment without stenting, and those with intracranial vascular imaging were analysed in our study, which assessed the age-specific prevalence of 50–99% intracranial stenosis and the associated stroke risk of 50–99% and 70–99% stenosis (adjusted for age and vascular risk factors) during follow-up to Sept 28, 2018.FindingsOf 1368 eligible patients with intracranial vascular imaging, 241 (17·6%) had 385 50–99% symptomatic or asymptomatic intracranial stenosis. The prevalence of symptomatic 50–99% intracranial stenosis increased from 29 (4·9%) of 596 at younger than 70 years to 10 (19·6%) of 51 at 90 years or older (ptrend<0·0001). Of 94 patients with 50–99% symptomatic intracranial stenosis, 14 (14·9%) had recurrent strokes (12 ischaemic and two haemorrhagic) during a median follow-up of 2·8 years (IQR 1·5–4·6). Although symptomatic intracranial stenosis conveyed an increased risk of ischaemic stroke compared with no intracranial stenosis (adjusted hazard ratio 1·43, 95% CI 1·04–1·96), the risk of same-territory ischaemic stroke in patients with 70–99% symptomatic intracranial stenosis tended to be less than those reported in the non-stenting groups of the previous trials (1-year risk 5·6% [95% CI 0·0–13·0] vs 9·4% [3·1–20·7] in VISSIT; 2-year risk 5·6% [0·0–13·0] vs 14·1% [10·1–19·4] in SAMMPRIS).InterpretationThe prevalence of 50–99% symptomatic intracranial stenosis increases steeply with age in predominantly Caucasian patients with transient ischaemic attack and minor ischaemic stroke. However, the risk of recurrent stroke on intensive medical treatment of symptomatic intracranial stenosis is consistent with the two previous randomised controlled trials in younger cohorts, supporting the generalisability of the trial results to routine practice.FundingWellcome Trust, Wolfson Foundation, British Heart Foundation, National Institute for Health Research, National Institute for Health Research Oxford Biomedical Research Centre, Association of British Neurologists.

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

Background: Intracranial arteriosclerotic disease (ICAD) is common in Asians and has been presumed to be largely associated with metabolic syndrome (MetS), but the risks for asymptomatic ICAD detectable in examinations of the brain, among other tests, are not well known. The present study is aimed at identifying the risks for asymptomatic ICAD using data on risk factors obtained in health checkups, including data from magnetic resonance imaging (MRI), chest computed tomography (CT), and neck echography. Methods: Subjects comprised 103 examinees more than equal to 40 years old (56.9 ± 4.7 years, 93 men) who underwent head MRI, chest CT, and carotid echography in the same period in a workplace health checkup between April and September 2014. Subjects were evaluated for ICAD based on stenosis of bilateral middle cerebral arteries and the basilar artery on previously reported scores from magnetic resonance angiography. Evaluations for extracranial arteriosclerotic disease (ECAD) were based on findings from carotid echography, and total calcium scores were calculated based on the number, areas, and peak Hounsfield computed tomographic numbers of the aortic arch calcified lesion detected. Results: ICAD, including mild cases with stenosis less than 50%, was seen in 21 subjects (20.3%); and MetS was evident in 12 subjects (11.7%). Logistic regression analysis with multivariate adjustment for major vascular risk factor demonstrated that echogenic of plaque was significantly associated with the ICAD (OR 3.69, 95%CI 1.02-13.3), however age was significant predictor of the risk profile in patients with ECAD. Conclusions: Carotid atherosclerosis could predict intracranial atherosclerosis in middle-aged people. However, further study with large sample size is warranted.

Author response: Sauna bathing reduces the risk of stroke in Finnish men and women: A prospective cohort study.

We thank Yu et al. for their comment on our article discussing the correlation between sauna bathing and reduction of stroke risk.1 Yu et al. infer that participants in our study were very likely to have major cervical or intracranial vessel stenosis based on average age. This assertion was based on 2 studies that reported the prevalence of asymptomatic carotid and intracranial stenosis in the general population to range from 0% to 5.7%.2,3 The figures were higher for men aged 80 years and above, and in Asian, Hispanic, and African American populations. It is unlikely these findings are applicable to our population, which comprised apparently healthy Caucasians aged 53–74 years without a known history of stroke at baseline. Furthermore, of the 197 men who took very frequent baths, only 8 had a stroke. Indeed, we agree that intracranial vasculature status is an important factor to take into account; however, we had no such imaging data available. As with epidemiologic observational studies, there is always a possibility of residual confounding. This bias was minimized by taking into account a comprehensive panel of confounders and conducting several sensitivity analyses. Our results are robust and consistent with previous research data4 and the compelling body of evidence on the beneficial physiologic changes associated with sauna bathing.5

Associations between fatty liver index and asymptomatic intracranial vertebrobasilar stenosis in Chinese population

Metabolic diseases such as type 2 diabetes mellitus (T2DM) and metabolic syndromes (MetS) have been recognized as the important risk factors for asymptomatic intracranial vertebrobasilar stenosis (IVBS). Although fatty liver index (FLI) is significantly related with these diseases, the association between FLI and IVBS remains unclear. In the present study, 2368 participants (30–75 years) were recruited from a Chinese prospective cohort study of PMMJS. Amongst them, 2281 individuals who did not have IVBS at baseline were enrolled in the 6-year following-up study. In cross-sectional analysis based on the baseline characteristics, the results showed that FLI was positively related with IVBS prevalence. Compared to the participants with FLI < 30, the adjusted OR (95% CI) of IVBS was 2.07 (1.18, 3.62) and 2.85 (1.39, 5.18) in the groups of 30 ≤ FLI < 60 and FLI ≥ 60, respectively. In longitudinal analysis, the results showed that the participants with FLI ≥ 60 had an increased risk of asymptomatic IVBS compared to those with FLI < 30 [adjusted HR (95%CI): 1.65 (1.05, 2.60)]. Moreover, exclusion of persons with hypertension, T2DM and MetS did not alter the associations between FLI and asymptomatic IVBS. Therefore, our results suggest that elevated FLI is an independent risk factor for asymptomatic IVBS in Chinese adults.

OP.1B.10] INTRACRANIAL STENOSIS IN FIRST-GENERATION CHINESE MIGRANTS WITH NEWLY DIAGNOSED DIABETES

Objective: Ethnic differences might influence the value of current approach to cardiovascular risk stratification. Intracranial atherosclerotic disease was indeed reported as a common cause of ischemic stroke among patients of Asian ancestry and stroke incidence in China is high. However, no study investigated the prevalence of intracranial stenosis (ICS) in Chinese migrants with newly diagnosed DM and the screening of vascular lesions is still mainly focused on the more accessible extracranial carotid artery. Present survey was thus performed to determine the prevalence of intracranial stenosis in Chinese migrants with newly diagnosed diabetes. Design and method: A cross-sectional community-based survey enrolled Chinese first generation migrants (n = 1200) and native Italians (n = 291) aged 35–59 years. Hypertension was diagnosed according to ESH guidelines. Diagnosis of DM was based on fasting plasma glucose criteria (more than 125 mg/dl confirmed by repeat testing), and/or current treatment with glucose-lowering drugs. Chinese patients with newly diagnosed diabetes were screened for intracranial stenosis using Doppler ultrasound. ICS (any degree of stenosis) was diagnosed when the peak flow velocity at Transcranial Doppler (TCD) was higher than: 120 cm/s for anterior cerebral arteries (ACA); 155 cm/s for middle cerebral arteries (MCA); 100 cm/s for posterior cerebral arteries (PCA); 100 cm/s for basilar artery (BA); 90 cm/s for intracranial vertebral arteries (VA). Results: DM was diagnosed in 168 (14.0%) and 21 (7.3%) participants in the Chinese and Italian cohorts respectively (age- and gender adjusted OR 2.29; 95% C.L. 1.41 to 3.72). Difference was not reduced when obesity and socioeconomic indexes were included in the model. Ninety-six Chinese patients with newly diagnosed DM accepted to undergo the screening of cerebral vascular lesions. No patient had carotid stenosis of any degree wheres per-person prevalence of intracranial stenosis was 18.2%. Nine out of the 17 patients with any intracranial stenosis (52%) had more than 1 intracranial lesions. Conclusions: The high prevalence of asymptomatic intracranial stenosis in Chinese patients with newly diagnosed diabetes emphasizes the importance of paying attention to intracranial vessels in this minority group.

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

Intracranial atherosclerotic stroke (ICAS) has various stroke mechanisms, including branch occlusive disease (BOD), subcortical infarcts caused by parent arterial disease occluding the perforator's orifice, and non-BOD, infarcts beyond the subcortical area caused by artery-to-artery embolism. To test whether these 2 types of ICAS had different vascular pathophysiologies, we compared the high-resolution magnetic resonance imaging characteristics between BOD and non-BOD ICAS. Eighty patients with acute infarcts caused by ICAS of proximal middle cerebral artery or basilar artery without carotid/cardiac embolic sources or nonatherosclerotic causes were enrolled (36 BOD and 44 non-BOD patients). The steno-occlusive intracranial artery at the maximal stenosis was analyzed for vascular remodeling and wall enhancement. BOD had distinct radiological features in terms of vascular morphology and enhancement. BOD showed a milder stenosis than non-BOD (P<0.001). Positive remodeling was more frequently observed in non-BOD than in BOD (P=0.005). Wall area index was also lower in BOD. Plaque enhancement was observed in all but one non-BOD patient and in one fourth of BOD patients (P=0.003). Although both types showed an eccentric enhancement, this enhancement was more frequently distributed in the BOD group on the side where the perforators arose. As the number of asymptomatic intracranial stenosis increased, the degree of stenosis (rho=0.513, P=0.003) increased in the BOD group, whereas enhanced plaque area (rho=0.343, P=0.030) increased in the non-BOD group. Our data indicate that BOD is a common and unique form of ICAS, distinct from non-BOD. These 2 types of ICAS have different vascular pathophysiologies in terms of vascular remodeling and plaque characteristics.

Recurrence in Intracranial Atherosclerotic Disease: A Stenosis-based Analysis

Intracranial atherosclerotic disease is a common cause of stroke; its incidence and prevalence vary widely by ethnicity. The aim of our study was to analyze the recurrence rate of cerebrovascular events in patients with symptomatic and asymptomatic intracranial stenosis (IS). We conducted a historical cohort study including all patients admitted in our hospital for stroke or transient ischemic attack (TIA) during 2011 and 2012 with information on intracranial circulation (ultrasonography and/or computed tomography angiography). We identified patients with symptomatic and asymptomatic IS and studied the recurrence of cerebrovascular events (TIA or ischemic stroke within the territory of the stenosis) for a minimum follow-up period of 6 months after the diagnosis of IS. For the recurrence rate estimation, patients with other potentially embolic diseases (in cervical arteries or heart) were excluded. We calculated the rate of recurrence of cerebrovascular events and performed Kaplan-Meier survival curves for symptomatic and asymptomatic IS. We investigated 1302 patients, mean age was 72.41 years (standard deviation 12.75). We identified 218 IS in 158 patients, 77 were symptomatic and 141 were asymptomatic. The recurrence rate of cerebrovascular events was 12.32 per 100 patient-years, with a mean time to recurrence of 1.73 months for symptomatic intracranial stenosis (SIS) and .88 per 100 patient-years for asymptomatic IS (P < .001). These results indicate a high risk of early recurrence of stroke in the territory of a SIS, highlighting the importance of its early diagnosis and aggressive treatment.

Prevalence of Intracranial Stenosis in a Norwegian Ischemic Stroke Population

There is no data about prevalence of intracranial stenosis (IS) in Northern Europe. This study aimed to investigate the prevalence of symptomatic and asymptomatic IS in a Norwegian, community-based ischemic stroke population. In a prospective study, all ischemic stroke or transient ischemic attack (TIA) patients were screened for IS by transcranial color-coded sonography, magnetic resonance angiography, and/or computed tomography angiography. Patients with IS and any cardiac arrhythmia or other possible causes of IS than atherosclerosis were excluded. IS was defined as symptomatic if the infarct/symptoms were related to the territory of the stenotic artery. Risk factors for cerebrovascular disease were registered on admission. During an 18-month study period, 607 patients had an ischemic stroke or a TIA. Out of 69 patients with IS (11.4%), 7 patients were excluded because having atrial fibrillation, and IS of possible atherosclerotic etiology was therefore diagnosed in 62 patients (10.2%). IS was symptomatic in 45 patients (7.4%). Diabetes mellitus was the only risk factor significantly associated with symptomatic IS (odds ratio 2.39, 95% confidence interval [CI] 1.03-5.54, P=.04). IS occurs in approximately 10% and is symptomatic in about 7% of a Norwegian ischemic stroke/TIA population. Diabetes mellitus appears to be the major risk factor for IS.

Clinical use of magnetic resonance plaque imaging for intracranial arteries.

To summarize the value and limitations of magnetic resonance (MR) plaque imaging for intracranial arteries. The data of MR plaque imaging of intracranial arteries in 422 patients performed in Peking Union Medical College Hospital from December 2006 to September 2010 were analyzed retrospectively. The success rate for MR plaque imaging of intracranial arteries was 97%. MR plaque imaging clearly displayed the wall structure of the arteries trunk (M1 segment of middle cerebral arteries, M2-3 segment of anterior cerebral arteries, and basilar arteries). Good inter-observer (k=0.91, 95% CI=0.80-1.03) and intra-observer reproducibility (k=0.96,95% CI=0.88-1.03) was observed in the evaluation of middle cerebral arteries' atherosclerosis. The wall features had significant difference between symptomatic and asymptomatic intracranial arteries'stenosis; compared with asymptomatic middle cerebral artery stenosis(35 cases), symptomatic middle cerebral artery stenosis(26 cases) had a significantly larger wall area (P=0.000), greater remodeling ratio (P=0.000), higher prevalence of expansive remodeling (outward expansion of the vessel wall) (P=0.003), and lower prevalence of constrictive remodeling (P=0.008). Arteritis of middle cerebral artery (3 cases) showed circular wall-thickening with apparent gadolinium-diethylene triamine pentaacetic acid-biotin enhancement. The MR plaque imaging is helpful in the evaluation of intracranial arteries stenosis, although it still has the limitations such as short scan range and low resolution.

The relationship of asymptomatic intracranial artery stenosis and Framingham stroke risk profile in a Northern Chinese industrial city

Background: Intracranial artery stenosis may be the most frequent cause of ischemic stroke in the world. Early detection of asymptomatic intracranial artery stenosis may allow for therapeutic intervention. Most elements of the Framingham stroke risk profile (FSRP) are also risk factors for intracranial artery stenosis. Thus, the FSRP might play a role in detecting asymptomatic intracranial artery stenosis.Objective: To investigate the relationship between the FSRP and asymptomatic intracranial artery stenosis.Methods: A sample of 5852 subjects (age >40 years) was selected from the KaiLuan study. All participants received transcranial Doppler ultrasound examinations to detect the presence and quantify the severity of intracranial arterial stenosis. Demographic and clinical variables were investigated at the time of examination. Binary logistic regression analyses was performed to determine the odds ratio of FSRP components to asymptomatic intracranial stenosis before and after adjusted for gender, body mass index (BMI), and total cholesterol (TC).Results: The subjects with intracranial artery stenosis were older than those without (68·2 versus 64·9), and the systolic blood pressure was higher in those with intracranial artery stenosis (146·86 versus 136·39). Among intracranial artery stenosis subjects, 77·5% had hypertension, 26·1% had diabetes, 8·9% had left ventricular hypertrophy, and 4·8% had atrial fibrillation. Logistic regression analyses revealed that age, systolic blood pressure, diabetes, atrial fibrillation, and left ventricular hypertrophy were risk factors for intracranial artery stenosis. The incidence of asymptomatic intracranial artery stenosis correlated with increasing FSRP scores. The odds ratios of intracranial artery stenosis from the lowest to the highest FSRP quartiles were as follows: 1 (reference group), 1·77 (95% CI: 1·23–2·56), 2·84 (95% CI: 2·02–3·98), 5·65 (95% CI: 4·03–7·93).Conclusion: FSRP plays an important role in detecting asymptomatic intracranial artery stenosis.

Natural History of Asymptomatic Intracranial Arterial Stenosis

The prevalence and natural history of asymptomatic intracranial arterial stenosis are not very well characterized. Existing data suggest that incidentally discovered asymptomatic intracranial stenosis presents a fairly low risk of stroke, though substantial uncertainty remains. Patients may be at greater risk if there are tandem stenoses. Methods to stratify the risk of stroke with asymptomatic intracranial atherosclerotic lesions have yet to be established and validated. In general, aggressive intervention for an asymptomatic intracranial stenosis is not currently recommended.

Prevalence and risk factors of asymptomatic intracranial vascular stenosis in patients with essential hypertension

Objective To investigate the clinical features and risk factors of asymptomatic intracranial vascular stenosis in patients with essential hypertension. Design and methods A total of 780 inpatients with essential hypertension were recruited. Patients with history of stroke, transient ischemic attack and other intracranial diseases were excluded. Intracranial vascular stenosis was detected by CT angiography (CTA), and clinical information, biochemical and special exam results were collected. Results Among 780 patients, 166 had asymptomatic intracranial vascular stenosis, the prevalence rate was 21.28%.

PO01-MO-16 The risk factors in patients with asymptomatic intracranial stenosis as evaluated by magnetic resonance angiography

PO01-MO-16 The risk factors in patients with asymptomatic intracranial stenosis as evaluated by magnetic resonance angiography

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.

Causes and Severity of Ischemic Stroke in Patients With Symptomatic Intracranial Arterial Stenosis

There are limited data on the causes and severity of subsequent stroke in patients presenting initially with TIA or stroke attributed to intracranial arterial stenosis. We evaluated the location, type (lacunar vs nonlacunar), cause, and severity of stroke in patients who had an ischemic stroke endpoint in the Warfarin Aspirin Symptomatic Intracranial Disease (WASID) trial. Of the 569 patients enrolled in the WASID trial, 106 patients (18.6%) had an ischemic stroke during a mean follow-up of 1.8 years. Stroke occurred in the territory of the symptomatic artery in 77 (73%) of 106 patients. Among the 77 strokes in the territory, 70 (91%) were nonlacunar and 34 (44%) were disabling. Stroke out of the territory of the symptomatic artery occurred in 29 (27%) of 106 patients. Among these 29 strokes, 24 (83%) were nonlacunar, 14 (48%) were attributed to previously asymptomatic intracranial stenosis, and 9 (31%) were disabling. Most subsequent strokes in patients with symptomatic intracranial artery stenosis are in the same territory and nonlacunar, and nearly half of the strokes in the territory are disabling. The most commonly identified cause of stroke out of the territory was a previously asymptomatic intracranial stenosis. Penetrating artery disease was responsible for a low number of strokes.

Prevalence and prognostic impact of microembolic signals in arterial sources of embolism

To compile available studies using microembolic signal (MES) detection by transcranial Doppler sonography in varying sources of arterial brain embolism. We investigated prevalences of MES and whether MES detection is of proven use for risk stratification. Studies reporting prevalences of MES and the risk of cerebral ischemic events were pooled for patients with symptomatic or asymptomatic carotid stenosis, intracranial artery stenosis, cervical artery dissection, and aortic embolism. MES were reported in 43% of 586 patients with symptomatic and in 10% of 1066 patients with asymptomatic carotid stenosis. Presence of one MES indicated an increased risk of future events [odds ratio (OR): 7.5, 95% confidence interval (CI): 3.6-15.4, p<0.0001 for symptomatic, and OR: 13.4, 95% CI: 6.5-27.4, p<0.0001 for asymptomatic disease). MES were reported in 25% of 220 patients with symptomatic vs. 0% of 86 patients with asymptomatic intracranial stenosis (p<0.0001), Of 82 patients with cervical artery dissection presenting with TIA or stroke, 50% had MES compared with 13% of 16 patients with local symptoms (p=0.006), In patients with aortic embolism, patients with plaques >or= 4 mm more frequently had MES compared with patients with smaller plaques (p=0.04), Data were insufficient to reliably predict future events in patients with intracranial stenosis, cervical artery dissection, and aortic embolism. MES are a frequent finding in varying sources of arterial brain embolism, MES detection is useful for risk stratification in patients with carotid stenosis.