Optimal Values of Flow Velocity on Transcranial Doppler in Grading Middle Cerebral Artery Stenosis in Comparison With Magnetic Resonance Angiography

Pressure-Poisson equation in numerical simulation of cerebral arterial circulation and its effect on the electrical conductivity of the brain

BACKGROUND AND OBJECTIVE

This study considers dynamic modeling of the cerebral arterial circulation and reconstructing an atlas for the electrical conductivity of the brain. Electrical conductivity is a governing parameter in several electrophysiological modalities applied in neuroscience, such as electroencephalography (EEG), transcranial electrical stimulation (tES), and electrical impedance tomography (EIT). While high-resolution 7-Tesla (T) Magnetic Resonance Imaging (MRI) data allow for reconstructing the cerebral arteries with a cross-sectional diameter larger than the voxel size, electrical conductivity cannot be directly inferred from MRI data. Brain models of electrophysiology typically associate each brain tissue compartment with a constant electrical conductivity, omitting any dynamic effects of cerebral blood circulation. Incorporating those effects poses the challenge of solving a system of incompressible Navier-Stokes equations (NSEs) in a realistic multi-compartment head model. However, using a simplified circulation model is well-motivated since, on the one hand, the complete system does not always have a numerically stable solution and, on the other hand, the full set of arteries cannot be perfectly reconstructed from the MRI data, meaning that any solution will be approximative.

METHODS

We postulate that circulation in the distinguishable arteries can be estimated via the pressure-Poisson equation (PPE), which is coupled with Fick's law of diffusion for microcirculation. To establish a fluid exchange model between arteries and microarteries, a boundary condition derived from the Hagen-Poisseuille model is applied. The relationship between the estimated volumetric blood concentration and the electrical conductivity of the brain tissue is approximated through Archie's law for fluid flow in porous media.

RESULTS

Through the formulation of the PPE and a set of boundary conditions (BCs) based on the Hagen-Poisseuille model, we obtained an equivalent formulation of the incompressible Stokes equation (SE). Thus, allowing effective blood pressure estimation in cerebral arteries segmented from open 7T MRI data.

CONCLUSIONS

As a result of this research, we developed and built a useful modeling framework that accounts for the effects of dynamic blood flow on a novel MRI-based electrical conductivity atlas. The electrical conductivity perturbation obtained in numerical experiments has an appropriate overall match with previous studies on this subject. Further research to validate these results will be necessary.

Circulating MicroRNAs as Potential Biomarkers for Ischemic Stroke in Patients with Asymptomatic Intracranial Artery Stenosis

Circulating microRNAs have been shown to be biomarkers of various diseases. We aimed to investigate whether circulating microRNA can serve as a biomarker to predict ischemic stroke risk in asymptomatic intracranial artery stenosis. A total of 716 participants from the Asymptomatic Polyvascular Abnormalities Community study who had asymptomatic intracranial artery stenosis at baseline were enrolled (2010-11). Patients who suffered incident ischemic stroke were classified into the case group, and age- and sex-matched individuals without stroke were used as controls. MicroRNA microarrays were used to distinguish baseline circulating serum microRNA levels between the case and the control groups (GEO accession number GSE201860). The differentially expressed microRNAs were validated by real-time PCR. MicroRNA microarrays were performed in baseline serum samples from12 subjects who developed ischemic stroke and 12 age- and sex-matched subjects without stroke during the 2014-15 follow-up period. Twenty microRNAs were differentially expressed between the two groups (fold change > 1.3 and p < 0.05 for all). Hsa-miR-486-5p, hsa-miR-92a-3p, hsa-miR-6089 from them were selected and validated in the baseline serum samples of ten subjects with incident ischemic stroke and another ten age- and sex-matched subjects without stroke during the 2016-17 follow-up period. Hsa-miR-1225-5p, with a large fold change value and a reported relationship with cardiovascular or cerebrovascular diseases, was also validated. Ultimately, only hsa-miR-6089 was differentially downregulated among patients with intracranial artery stenosis who developed ischemic stroke (p < 0.05). In patients with asymptomatic intracranial artery stenosis, downregulated serum hsa-miR-6089 may be associated with the risk of ischemic stroke.

Association Between Cumulative Exposure to Increased Low-Density Lipoprotein Cholesterol and the Prevalence of Asymptomatic Intracranial Atherosclerotic Stenosis

Background and Purpose: Intracranial atherosclerosis has gained increasing attention due to the high risk of recurrent clinical or subclinical ischemic events, while the relationship between low-density lipoprotein cholesterol (LDL-C) measured at a single time point and intracranial atherosclerotic stenosis (ICAS) is inconsistent. This study aims to assess the association between cumulative exposure to increased LDL-C and the prevalence of asymptomatic ICAS.

Methods: The Asymptomatic Polyvascular Abnormalities Community study was investigated on the epidemiology of asymptomatic polyvascular abnormalities in Chinese adults. In this study, we included 4,523 participants with LDL-C measured at 3 examinations in 2006, 2008, and 2010. Cumulative exposure to increased LDL-C was calculated as following: LDL-C burden_2006−2008 = [(LDL-C₂₀₀₆-1.8) + (LDL-C₂₀₀₈-1.8)]/2 ^* time_2006−2008; LDL-C burden = LDL-C burden_2006−2008 + LDL-C burden_2008−2010. Transcranial doppler ultrasonography was performed in 2010 to detecting the ICAS.

Results: Of the 4,347 patients, 13.3% (580/4,347) were diagnosed with ICAS. In univariate analysis, the association between LDL-C burden and ICAS prevalence was significant, the odds ratios (95% confidence interval) from the lowest to the highest quartile were 1 (reference), 1.30 (0.99–1.70), 1.32 (1.01–1.73), and 2.14 (1.66–2.75), respectively (P < 0.05). After adjustment for potential confounding factors, the same result was reached.

Conclusions: Cumulative exposure to increased LDL-C is concentration-dependently associated with increased prevalence of asymptomatic ICAS, especially in those under the age of 65 y or free of hypertension, diabetes mellitus, and hyperlipidemia.

No association between postmenopausal time and the prevalence of newly discovered asymptomatic intracranial atherosclerotic stenosis: The APAC study

INTRODUCTION

Asymptomatic intracranial atherosclerotic stenosis (AICAS) is a common cause of stroke. Elderly women were more likely than men to develop AICAS, although it indicated that a lifelong exposure to estrogen could lower the risks of cardiovascular disease (CVDs).

OBJECTIVE

The present study aims to ascertain whether postmenopausal time is a risk factor of AICAS. Fostering a correct perception of menopause is of great significance for the overall well-being of the elderly women.

METHODS

All participants received a questionnaire, physical examination, laboratory testing and transcranial Doppler. The menopausal population (n = 701) was divided into three groups by tertiles of postmenopausal time. Two-tailed testing and trend test were used to reveal the relationship between postmenopausal time and newly discovered AICAS. Other potential risk factors were also analyzed to ascertain whether there was a relation between postmenopausal time and the newly discovered ICAS.

RESULTS

Both mean age and mean postmenopausal time were gradually increased from G0 to G2. The same trend occurred in hypertension, diabetes mellitus, total cholesterol, triglyceride, C-reactive protein and serum homocysteine. Adjusting for various confounding factors, postmenopausal time was not a risk factor for newly discovered AICAS. Multifactor analysis and stratifying analysis showed no correlation between newly discovered AICAS and postmenopausal time.

CONCLUSIONS

Postmenopausal time is not an independent risk factor of AICAS. No relationship was detected between postmenopausal time and newly discovered AICAS, while vigorous control of body weight, blood pressure/glucose/lipids and smoke cessation are vital for preventing the occurrence of AICAS.

A New Transcranial Doppler Scoring System for Evaluating Middle Cerebral Artery Stenosis

BACKGROUND AND PURPOSE

Transcranial Doppler (TCD) criteria for cerebrovascular stenosis are only based on velocity with unsatisfactory positive predictive value (PPV) in previous studies. We refined a published scoring system that integrates several characteristics of TCD data in diagnosing middle cerebral artery (MCA) stenosis.

METHODS

Using the TCD-digital subtraction angiography (DSA) database from Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) trial, velocity, spectrum pattern, diffuse ratio, and asymmetry ratio were assessed. The cutpoints were defined for each parameter and a point value was assigned to each category within that parameter. A summed score was calculated for each MCA. The accuracy was assessed for different cutpoints in predicting ≥50% MCA stenosis measured by DSA. Logistic regression and C-statistics were used for analysis.

RESULTS

A total of 114 MCAs were included in vessel-based and 87 patients were included in patient-based analysis. Compared to the velocity-only cutpoints in SONIA, the score results in much improved PPV while negative predictive value (NPV) remains unchanged. The score based on mean velocity (score 0: <140 cm/s, score 3: ≥140 cm/s), spectrum pattern (score 0: no turbulence; score 1: mild turbulence; 2: significant turbulence), and asymmetry ratio (score 0: ratio <1.5, score 1: ratio 1.5-2; score 2: ratio ≥2.1) has the highest NPV while PPV remains favorable (PPV: 72% [95% CI 54-90%]; NPV: 84% [95% CI: 75-93%], area under curve [AUC]: .76 [95% CI: .66-.86]).

CONCLUSIONS

The multiparameter scoring system incorporating several characteristics of TCD measures yielded higher PPV while maintaining high NPV compared with the single-parameter velocity criteria in diagnosing MCA ≥50% stenosis.

The prevalence of intracranial stenosis in patients at low and moderate risk of stroke

Background:

Previous studies assessing the risk of stroke in the general population performed screening with Doppler ultrasonography only for high-risk patients and neglected low- and moderate-risk patients. The aims of this study were to explore the current prevalence of intracranial arterial stenosis (ICAS) and analyze its association with different levels of stroke risk and risk factors based on the risk assessment scale for stroke used in China.

Methods:

A total of 3654 participants who underwent transcranial Doppler ultrasound (TCD) were eligible for inclusion. Information regarding demographic characteristics and risk factors such as alcohol consumption and hypertension was collected through interviews and questionnaires and used to analyze the association of ICAS with different levels of stroke risk and risk factors.

Results:

The mean age of 501 subjects diagnosed with at least one ICAS was higher than that of participants without ICAS (57.13 ± 9.56 years and 55.52 ± 9.35 years, respectively). After adjusting for confounding factors, gender, education, residence, hypertension and personal history of stroke were associated with ICAS. The odds ratios for ICAS in patients with hypertension and a personal history of stroke were 1.655 [95% confidence interval (CI): 1.341–2.043] and 1.854 (95% CI: 1.371–2.508), respectively. In addition, participants in the low- and moderate-risk stroke groups accounted for an unexpectedly high proportion of individuals with ICAS (up to 38.3%). Results from multivariate analyses indicated that the adjusted odds ratios for ICAS in patients with moderate and high stroke risks versus those with a low stroke risk were 1.603 (95% CI: 1.171–2.195) and 1.612 (95% CI: 1.272–2.042), respectively.

Conclusion:

The prevalence of ICAS is high in northeast China and increases with the level of stroke risk. However, the proportion of patients with ICAS among those with low and moderate stroke risks should also be noted.

Association between fasting Triglyceride levels and the Prevalence of Asymptomatic Intracranial Arterial Stenosis in a Chinese Community-based Study

The aim of this study was to assess the association between fasting triglyceride (FTG) levels and the prevalence of asymptomatic intracranial arterial stenosis (ICAS). The Asymptomatic Polyvascular Abnormalities Community (APAC) study is a sub-population of the Kailuan study which targeting on the epidemiology of asymptomatic polyvascular abnormalities in Chinese adults. A total number of 5345 participants, aged ≥40, and without history of stroke, transient ischemic attack, and coronary heart disease were enrolled in this study. Transcranial Doppler Ultrasonography was performed for the detection of ICAS presence. Out of 5345 participants, 698 subjects diagnosed ICAS (13.1%). In univariate analysis, the association between fasting TG (FTG) levels and asymptomatic ICAS didn’t reach statistical significance (OR: 0.99, 95% CI: 0.89–1.09; P = 0.79), the same conclusion was reached in multivariate analysis, after adjustment for age, sex (OR: 1.05, 95% CI: 0.95–1.17) and age, sex, current smoking status, hypertension, diabetes, body mass index, estimated glomerular filtration rate, total cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol (OR: 0.95, 95% CI: 0.84–1.06), respectively. FTG failed to show any statistical significance on ICAS presence in the APAC study, but the TG actually plays an important role in the progression of atherosclerosis as a biomarker.

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.

Dynamic Cerebral Autoregulation Assessment Using Extracranial Internal Carotid Artery Doppler Ultrasonography

Transcranial Doppler ultrasonography of the middle cerebral artery (MCA) is frequently used to assess dynamic cerebral autoregulation (dCA); however, this is difficult in patients with poor temporal bone windows. In the study described here, we investigated the agreement and sensitivity of dCA indices determined from the extracranial internal carotid artery (ICA) and those determined from the MCA. Measurements for 32 stroke patients and 59 controls were analyzed. Measurement of the mean flow correlation index (Mx) and transfer function analysis based on spontaneous blood pressure fluctuation were simultaneously performed for the extracranial ICA and MCA. The mean values of Mx and phase shift did not significantly differ between the ICA and MCA (mean difference: Mx = 0.01; phase shift of very low frequency [VLF] = 0.7°, low frequency [LF] = 3.3° and high frequency = 4.5°), but the gains in VLF and LF in the ICA were significantly lower than those in the MCA (mean difference: gain of VLF = -0.13, gain of LF = -0.10). The intra-class correlation coefficient between the dCA indices of the ICA and MCA was favorable in Mx (0.76) and the phase shift of VLF (0.72). The area under the receiver operating characteristic curve for stroke diagnosis did not differ among the dCA indices. We conclude that dCA assessed from the ICA is as effective as that from the MCA, but the results are not interchangeable.

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

Background

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

Methods

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

Results

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

Conclusions

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

Association between High-density-lipoprotein-cholesterol Levels and the Prevalence of Asymptomatic Intracranial Arterial Stenosis

Intracranial atherosclerotic stenosis (ICAS) is a common cause of ischemic stroke, and a low level of high-density lipoprotein cholesterol (HDL-C) is also considered to be a predictor for stroke. However, the association between the HDL-C level and asymptomatic ICAS is uncertain. From 2010 to 2011, a random sample of 5,351 participants were enrolled in the Asymptomatic Polyvascular Abnormalities Community (APAC) study. The recruited participants were then separated into 5 roughly uniform-sized factions with varying HDL-C levels. Multivariate logistic regression was implemented to assess the connection of the HDL-C levels and the prevalence of asymptomatic ICAS. The prevalence of asymptomatic ICAS showed no gradual decrease with the increase of HDL-C levels. After adjustment for conventional risk factors, HDL-C levels still showed no significant association with asymptomatic ICAS. The odds ratios (OR) of the prevalence of asymptomatic ICAS between the first group and the other 4 groups were 0.98, 1.00, 0.92, and 0.87 with 95% confidence intervals (CI) being 0.76–1.27, 0.78–1.29, 0.71–1.19, and 0.66–1.13, respectively. The study showed little correlation between HDL-C levels and asymptomatic ICAS. Normal levels of HDL-C are not an independent risk factor for asymptomatic ICAS.

Peak Systolic Velocity Measurements with Transcranial Doppler Ultrasound Is a Predictor of Incident Stroke among the General Population in China

BACKGROUND AND OBJECTIVE

It is necessary to develop an effective and low-cost screening tool for identifying Chinese people at high risk of stroke. Transcranial Doppler ultrasound (TCD) is a powerful predictor of stroke in the pediatric sickle cell disease population, as demonstrated in the STOP trial. Our study was conducted to determine the prediction value of peak systolic velocities as measured by TCD on subsequent stroke risk in a prospective cohort of the general population from Beijing, China.

METHODS

In 2002, a prospective cohort study was conducted among 1392 residents from 11 villages of the Shijingshan district of Beijing, China. The cohort was scheduled for follow up with regard to incident stroke in 2005, 2007, and 2012 by a study team comprised of epidemiologists, nurses, and physicians. Univariate and multivariate Cox proportional hazard regression models were used to determine the factors associated with incident stroke.

RESULTS

Participants identified by TCD criteria as having intracranial stenosis had a 3.6-fold greater risk of incident stroke (hazard ratio (HR) 3.57, 95% confidence interval (CI) 1.86-6.83, P<0.01) than those without TCD evidence of intracranial stenosis. The association remained significant in multivariate analysis (HR 2.53, 95% CI 1.31-4.87) after adjusting for other risk factors or confounders. Older age, cigarette smoking, hypertension, and diabetes mellitus remained statistically significant as risk factors after controlling for other factors.

CONCLUSIONS

The study confirmed the screening value of TCD among the general population in urban China. Increasing the availability of TCD screening may help identify subjects as higher risk for 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.

Long-term risk of cardiovascular disease among type 2 diabetic patients with asymptomatic intracranial atherosclerosis: a prospective cohort study

OBJECTIVE

To investigate whether asymptomatic middle cerebral artery (MCA) stenosis is associated with risk of cardiovascular disease (CVD) in Chinese with type 2 diabetes.

METHODS

In this prospective cohort study, 2,144 Hong Kong Chinese with type 2 diabetes and without history of stroke or atrial fibrillation were recruited in 1994-1996 and followed up for a median of 14.51 years. Participants were assessed at baseline for MCA stenosis using transcranial Doppler. We performed survival analysis to assess the association between asymptomatic MCA stenosis and first CVD event, defined as ischemic stroke, acute coronary syndrome (ACS) or cardiovascular death.

RESULTS

Of the 2,144 subjects, MCA stenosis at baseline was detected in 264 (12.3%). Rates of stroke, ACS and cardiovascular death per 100 were, respectively, 2.24, 2.92 and 1.11 among participants with stenosis, higher than among those without stenosis. Ten-year cumulative occurrence of stroke, ACS and cardiovascular death in subjects with MCA stenosis was 20%, 24% and 10%, respectively, higher than the corresponding values for subjects without stenosis(all P<0.001). After adjusting for covariates, MCA stenosis was found to be an independent predictor of stroke [hazard ratio (HR) 1.40, 95%CI 1.05-1.86; P = 0.02], ACS (HR 1.35, 95%CI 1.04-1.75; P = 0.02) and cardiovascular death(HR 1.56, 95%CI 1.04-2.33; P = 0.03).

CONCLUSIONS

Asymptomatic MCA stenosis is a risk factor for CVD in Chinese with type 2 diabetes, and detection of asymptomatic MCA stenosis by transcranial Doppler can identify diabetic individuals at high risk of future CVD. This finding is particularly important for diabetic individuals in Asia, where intracranial atherosclerosis is common.

Safety and Feasibility of Remote Limb Ischemic Preconditioning in Patients With Unilateral Middle Cerebral Artery Stenosis and Healthy Volunteers

Previous studies have indicated a neuroprotective effect of remote limb ischemic preconditioning. The aim of the present study was to assess whether upper arm ischemic preconditioning is feasible and safe in patients with unilateral middle cerebral artery (MCA) stenosis compared to healthy volunteers. Ten patients with unilateral MCA stenosis and 24 healthy volunteers underwent limb ischemic preconditioning, consisting of five cycles of 5-min inflations of a blood pressure cuff to 200 mmHg around an upper limb followed by 5 min of reperfusion. Limb ischemic preconditioning has no significant effect on the heart rate, oxygenation index, or mean flow velocity in patients with unilateral MCA stenosis or healthy volunteers. However, healthy volunteers showed a reduction in blood pressure 30 min following reperfusion of the last cycle. Limb ischemic preconditioning was found to be safe and well tolerated in both patients and healthy volunteers. We highlight the potential of limb ischemic preconditioning as an adjunct to neuroprotective treatment.

Elevated plasma total cholesterol level is associated with the risk of asymptomatic intracranial arterial stenosis

Background

Intracranial arterial stenosis (ICAS) is one of the most common causes of stroke, and dyslipidemia was one of the most common risk factors related to ICAS. However, the correlation between the plasma total cholesterol level (PTC) and ICAS, especially asymptomatic ICAS (AICAS) is not clear.

Materials and Methods

5,300 participants were enrolled in this study. The diagnosis of AICAS was made by transcranial Doppler ultrasonography. The participants were then divided into 5 essentially equal-sized groups based on their PTC levels. The multivariate logistic regression was used to analyze the correlation between the PTC level and the prevalence of AICAS.

Results

13.0% of the participants were diagnosed with AICAS. The prevalence of AICAS gradually increased with the increasing PTC level. After adjusted by the possible confounding factors, the Odds Ratios (OR) of the AICAS prevalence between the 1st quintile group and the other 4 groups were 1.13, 1.23, 1.63 and 1.75 with 95% confident intervals (CI) of 0.84–1.52, 0.91–1.66, 1.20–2.22 and 1.23–2.47, respectively. The further subgroup analysis revealed that the PTC level was stronger for males (OR 1.42 95%CI 1.23–1.64), regarding the prevalence of AICAS.

Conclusions

In this large community-based study, the prevalence of AICAS is 13.0%, subjects with higher PTC levels showed a mild increase in the prevalence of AICAS. The PTC level is an independent risk factor of AICAS. Males seem to be significantly more vulnerable to the risk of AICAS.

Associations of high sensitivity C-reactive protein levels with the prevalence of asymptomatic intracranial arterial stenosis

BACKGROUND AND PURPOSE

High sensitivity C-reactive protein (hs-CRP), an inflammatory biomarker, has been demonstrated to contribute to the process of atherosclerosis and artery stenosis. The aim of this study was to evaluate whether hs-CRP level is associated with asymptomatic intracranial artery stenosis (ICAS).

METHODS

A random sample of 5440 participants aged 40 years or older (40.1% women) were enrolled in the Asymptomatic Polyvascular Abnormalities Community study in 2010-2011. Information on the potential risk factors for ICAS was collected and the presence of ICAS was assessed by transcranial Doppler in 5309 participants. Participants were stratified into three groups according to hs-CRP levels. A multivariate logistic regression was used to examine the association between hs-CRP levels and asymptomatic ICAS.

RESULTS

The prevalence of asymptomatic ICAS was 13.2% in this cohort. The median of hs-CRP levels was positively associated with the increasing numbers of ICASs. After adjusting for possible risk factors, hs-CRP ≥ 3 mg/l remained significantly associated with asymptomatic ICAS (odds ratio 1.28, 95% confidence interval 1.02-1.61).

CONCLUSIONS

In this large community-based study, subjects with higher hs-CRP levels showed a mild increase in the prevalence of asymptomatic ICAS, independent of traditional vascular risk factors. hs-CRP is an independent predictor of asymptomatic ICAS and intracranial atherosclerotic burden.

Association between non-high-density-lipoprotein-cholesterol levels and the prevalence of asymptomatic intracranial arterial stenosis

Objective

The aim of this study was to assess the association between non-high-density-lipoprotein-cholesterol (non-HDL-C) and the prevalence of asymptomatic intracranial arterial stenosis (ICAS).

Methods and Results

The Asymptomatic Polyvascular Abnormalities Community (APAC) study is a prospective cohort study based on the Kailuan district (China) population. A total of 5351 eligible subjects, aged ≥40, and without history of stroke or myocardial infarction, were enrolled in this study. Transcranial Doppler Ultrasonography (TCD) was performed on all enrolled subjects for the evaluation of ICAS presence. Out of 5351 patients, 698 subjects showed evidence of ICAS (prevalence of 13.04%). Multivariate analysis showed that non-HDL-C is an independent indicator for the presence of ICAS (OR  = 1.15, 95%CI: 1.08 – 1.23), but with a gender difference (P for interaction<0.01): in men, non-HDL-C is an independent indicator for ICAS (multivariate-adjusted OR  = 1.28, 95%CI: 1.18–1.39), but not in women (multivariate-adjusted OR  = 1.03, 95%CI: 0.93–1.14). Subjects were divided into five subgroups based non-HDL-C levels and these levels correlated linearly with the prevalence of ICAS (P for trend <0.01). Compared with the first quintile, multivariate-adjusted OR (95%CI) of the second, third, fourth and fifth quintiles were: 1.05 (0.71–1.56), 1.33 (0.91–1.95), 1.83 (1.27–2.63), 2.48 (1.72–3.57), respectively.

Conclusion

Non-HDL-C is an independent predictor of ICAS prevalence in men but not in women, suggesting that non-HDL-C levels could be used as a surveillance factor in the primary prevention of ischemic stroke, especially in men.

Ideal cardiovascular health metrics on the prevalence of asymptomatic intracranial artery stenosis: a cross-sectional study

Background and Purpose

Intracranial Artery Stenosis (ICAS) is one of the most common causes of ischemic stroke in Asia. Previous studies have shown the number of ideal cardiovascular health (CVH) metrics was associated with lower risk of stroke. This study aimed to investigate the relationship between ideal CVH metrics and prevalence of ICAS.

Methods

A random sample of 5,412 participants (selected from Kailuan Study as a reference population) aged 40 years or older (40.10% women), free of stroke, transient ischemic attack, and coronary disease, were enrolled in the Asymptomatic Polyvascular Abnormalities Community study from 2010 to 2011. We collected information on the seven CVH metrics (including smoking, body mass index, dietary intake, physical activity, blood pressure, total cholesterol and fasting blood glucose); and assessed ICAS by transcranial Doppler. The relationship between the ideal CVH metrics and prevalence of ICAS was analyzed using the multivariate logistic regression.

Results

After adjusting for age, sex, and other potential confounders, the adjusted odds ratios(95% confidence interval) for ICAS were 0.76(0.58–0.99), 0.55(0.43–0.72), 0.49(0.37–0.65), 0.43(0.31–0.61), and 0.36(0.22–0.62), respectively, for those having 2, 3, 4, 5, and 6–7 ideal CVH metrics compared with those having 0–1 ideal metric(p-trend<0.0001). Similar inverse associations were observed in different age and gender groups (all p-trends<0.05).

Conclusion

We found a clear gradient relationship between the number of ideal CVH metrics and lower prevalence of ICAS in a Chinese population, which supports the importance of ideal health behaviors and factors in the prevention of ICAS.

Reevaluating the transcranial Doppler criteria for estimation of anterior circulation artery stenosis: transcranial Doppler sonography versus digital subtraction angiography

OBJECTIVES

The criteria for evaluating cerebral artery stenosis by transcranial Doppler sonography are inconsistent. We aimed to identify the accuracy of transcranial Doppler criteria compared with digital subtraction angiography for diagnosis of anterior circulation artery stenosis.

METHODS

A total of 170 patients who underwent transcranial Doppler sonography and digital subtraction angiography were recruited. The anterior circulation arteries were evaluated by transcranial Doppler sonography and digital subtraction angiography. We defined the best cutoff value for substantial anterior circulation artery stenosis by receiver operating characteristic curve analyses and calculated the sensitivity, specificity, and positive and negative predictive values.

RESULTS

An anterior circulation artery peak systolic velocity (PSV) of 120 cm/s had the largest area under the receiver operating characteristic curve compared with PSVs of 110, 130, and 140 cm/s and mean flow velocities of 60, 70, and 80 cm/s. The sensitivity, specificity, false-positive rate, false-negative rate, accuracy, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and Youden index for transcranial Doppler sonography were 90.6%, 85.0%, 15.0%, 9.4%, 87.9%, 87.2%, 88.9%, 6.04, 0.11, and 0.756, respectively. The reliability index included the agreement rate and κ value, which were 87.9% and 0.757.

CONCLUSIONS

A PSV of 120 cm/s combined with additional parameters was an accurate criterion for diagnosing anterior circulation artery stenosis. Transcranial Doppler sonography could be considered a valuable method for screening diagnosis of cerebral artery stenosis.

Velocity criteria for intracranial stenosis revisited: an international multicenter study of transcranial Doppler and digital subtraction angiography

BACKGROUND AND PURPOSE

Intracranial atherosclerotic disease is associated with a high risk of stroke recurrence. We aimed to determine accuracy of transcranial Doppler screening at laboratories that share the same standardized scanning protocol.

METHODS

Patients with symptoms of cerebral ischemia were prospectively studied. Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) criteria were used for identification of ≥50% stenosis. We determined velocity cutoffs for ≥70% stenosis on digital subtraction angiography by Warfarin-Aspirin Symptomatic Intracranial Disease criteria and evaluated novel stenotic/prestenotic ratio and low-velocity criteria.

RESULTS

A total of 102 patients with intracranial atherosclerotic disease (age 57±13 years; 72% men; median National Institutes of Health Stroke Scale 3, interquartile range 6) provided 690 transcranial Doppler/digital subtraction angiography vessel pairs. On digital subtraction angiography, ≥50% stenosis was found in 97 and ≥70% stenosis in 62 arteries. Predictive values for transcranial Doppler SONIA criteria were similar (P>0.9) between middle cerebral artery (sensitivity 78%, specificity 93%, positive predictive value 73%, negative predictive value 94%, and overall accuracy 90%) and vertebral artery/basilar artery (69%, 98%, 88%, 93%, and 92%). As a single velocity criterion, most sensitive mean flow velocity thresholds for ≥70% stenosis were: middle cerebral artery>120 cm/s (71%) and vertebral artery/basilar artery>110 cm/s (55%). Optimal combined criteria for ≥70% stenosis were: middle cerebral artery>120 cm/s, or stenotic/prestenotic ratio≥3, or low velocity (sensitivity 91%, specificity 80%, receiver operating characteristic 0.858), and vertebral artery/basilar artery>110 cm/s or stenotic/prestenotic ratio≥3 (60%, 95%, 0.769, respectively).

CONCLUSIONS

At laboratories with a standardized scanning protocol, SONIA mean flow velocity criteria remain reliably predictive of ≥50% stenosis. Novel velocity/ratio criteria for ≥70% stenosis increased sensitivity and showed good agreement with invasive angiography.

Validation of transcranial Doppler with magnetic resonance angiography in acute cerebral ischemia

BACKGROUND AND PURPOSE

Transcranial Doppler (TCD) is often used as a screening tool for detecting intracranial stenosis. Since TCD results may vary among laboratories and sonographers, it requires validation against an imaging modality. We evaluated diagnostic accuracy of TCD performed in our laboratory against time-of-flight (TOF) magnetic resonance angiography (MRA) in detecting intracranial stenosis in patients with acute cerebral ischemia.

METHODS

Consecutive patients with acute (<24 hours) cerebral ischemia and intracranial arterial stenosis on MRA underwent both TCD and MRA within 5 hours of each other. TCD was performed by credentialed neurosonologists according to standardized protocol. An independent neuroradiologist interpreting MRA was blinded to TCD findings. We evaluated TCD peak systolic velocities (PSV) in proximal intracranial arteries as predictive of moderate (>50%) and severe (>70%) stenosis on TOF-MRA.

RESULTS

One hundred and fifty patients (74% males; mean age 53 years) underwent neurovascular evaluation with TCD and MRA. Twenty-two (14.6%) patients were excluded due to absent temporal acoustic windows. Middle cerebral artery TCD PSV values of >140 cm/s and >180 cm/s were found to predict a >50% and >70% focal stenosis, respectively. Optimal cut-off PSV values for other major proximal intracranial arteries were also established.

CONCLUSIONS

TCD performed in our laboratory shows satisfactory agreement with TOF-MRA in diagnosis and grading of proximal intracranial stenosis in patients with acute cerebral ischemia.

10 questions about intracranial atherosclerotic stenosis

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

Plasma level of sICAM-1 is associated with the extent of white matter lesion among asymptomatic elderly subjects

OBJECTIVE

Inflammatory endothelial activation mediated by intercellular adhesion molecule-1 (ICAM-1) plays a role in the pathogenesis of large- and small-vessel disease. We explored the association between soluble ICAM-1 (sICAM-1) and white matter lesion (WML) as a manifestation of cerebral small-vessel disease.

METHODS

One hundred and seventy-five elderly individuals aged >or= 60 without neurological deficits were studied. Subcortical deep white matter hyperintensity (SDWMH) and periventricular hyperintensity (PVH) were rated separately. Lesions in each category were then divided into three groups (grade 0-I, grade II, grade III) according to the Fazekas scale.

RESULTS

Plasma sICAM-1 levels were positively associated with grades of WML (for SDWMH: 297.4+/-135.6ng/mL in grade 0-I, 391.3+/-145.5ng/mL in grade II, and 450.2+/-232.9ng/mL in grade III, p<0.001; for PVH: 282.5+/-116.5ng/mL in grade 0-I, 402.3+/-160.4ng/mL in grade II, and 428.1+/-227.7ng/mL in grade III, p<0.001). Multivariate analysis showed higher sICAM-1 levels, age and hypertension were the independent risk factors associated with the presence and severity of WML. More than 4-fold increased risk of WML was observed in patients with the highest quartile of sICAM-1 (all WML OR=4.694, 95% CI: 1.805-12.204; moderate WML OR=4.618, 95% CI: 1.543-13.825; severe WML OR=4.893, 95% CI: 1.236-19.368).

CONCLUSION

Increased plasma sICAM-1 suggests inflammatory process may be involved in the pathogenesis of WML.

The accuracy of transcranial Doppler in the diagnosis of middle cerebral artery stenosis

BACKGROUND AND PURPOSE

It was the aim of this study to systematically review available literature on the accuracy of transcranial Doppler (TCD) compared with angiography for the diagnosis of > or =50% middle cerebral artery stenosis in patients with transient ischemic attack or ischemic stroke.

METHODS

We performed a systematic review that included original articles published on TCD accuracy from 1982 until the end of December 2005 using angiography as the gold standard. The following measures of diagnostic accuracy were obtained from each primary study: sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Weighted mean averages were then calculated from individual results for different velocity cutoffs.

RESULTS

Six papers met our selection criteria. Using laboratory-specific variable mean flow velocity cutoffs, self-reported best accuracy results yield a mean weighted average sensitivity of 92%, specificity of 92%, PPV of 88% and NPV of 98% for 80 cm/s cutoff. For 100 cm/s cutoff, the sensitivities were 100%, specificity 97%, PPV 88% and NPV 100%.

CONCLUSIONS

Although limited to few reports, this analysis demonstrates fair TCD performance against angiography. Since increasing velocity cutoffs do not yield decreasing sensitivity and increasing specificity, further studies are required to determine optimal velocity values and possibly other criteria such as velocity ratios to develop a screening test with balanced performance parameters.

A large-scale study on relationship between cerebral blood flow velocity and blood pressure in a natural population

In order to verify the relationship between blood pressure and cerebral blood flow velocity in sub-clinical natural population, 1294 middle-aged and old Beijing rural residents were investigated in autumn 2002. For all subjects, systolic blood flow velocities (V(s)) in common carotid artery (CCA), internal carotid artery (ICA) and middle cerebral artery (MCA) were detected with trans-cranial Doppler. Key factors such as anthropometry, medication use, blood pressure and blood biochemical analysis were investigated at the same time. After controlling for age, gender, diabetes, hypercholesterolaemia, smoking and body mass index, multivariate analysis showed that systolic blood pressure (SBP) correlated positively with V(s) at MCA and slight negatively correlated with at CCA. As blood pressure rose by 10 mm Hg, the V(s) at MCA increased by 1.63 cm/s. Duration of hypertension (HD) negatively correlated with V(s) at MCA (P<0.01). The V(s) at MCA in early-stage and chronic hypertensive patients were 92.9+/-1.9 and 84.1+/-2.3 cm/s, respectively. Antihypertensive treatment could modify the V(s) at MCA towards a normal level by lowering blood pressure. In conclusion, the effect of hypertension on cerebral blood flow is complex. V(s) at MCA positively correlated with SBP, but negatively related to HD. Antihypertensive treatment might be helpful to keep cerebral blood flow at a normal level.

Relationship between cerebral vasomotor reactivity and white matter lesions in elderly subjects without large artery occlusive disease

BACKGROUND AND PURPOSE

The relationships between cerebral vasomotor reactivity (CVR) and white matter lesions (WMLs) were investigated mainly in patients with carotid stenosis. We aimed to study the relationship in asymptomatic elderly subjects without large artery occlusive disease.

METHODS

A total of 33 elderly individuals (mean age was 76.2 years) who were free from neurological deficit or cognitive impairment were studied. Bilateral mean blood flow velocity was measured in the middle cerebral artery using a 2-MHz pulsed transcranial Doppler (TCD) system together with intravenous administration of acetazolamide as vasodilatory stimuli. WMLs on a fluid-attenuated inversion recovery (FLAIR) sequence of MRI were classified into two categories: subcortical deep white matter hyperintensity (SDWMH) and periventricular hyperintensity (PVH). The lesions in each category were then divided into three grades (grade 0-I, grade II, grade III) according to the Fazekas scale.

RESULTS

CVR was inversely associated with the extent of SDWMH and PVH. The differences in CVR were statistically significant among different severity of WMLs: for SDWMH (70%+/- 10% in grade 0-I, 60%+/- 10% in grade II, and 40%+/- 10% in grade III, P < .001); for PVH (80%+/- 10% in grade 0-I, 60%+/- 10% in grade II, and 40%+/- 10% in grade III, P < .001).

CONCLUSIONS

Impaired CVR is related to the extent of WMLs in asymptomatic elderly individuals without large artery stenosis. The findings in our study suggest that dysfunction of cerebral vascular autoregulation might be an important factor in the development of WMLs in the asymptomatic elderly without large artery occlusive disease.

Gender and risk factor dependence of cerebral blood flow velocity in Chinese adults

BACKGROUND AND PURPOSE

The objective of this study is to determine if and how cerebral blood flow velocity and stroke risk factors are related in a stroke free population.

METHODS

This cross-sectional study recruited 1323 stroke-free subjects, aged 42-73 years, from a county region in China. Systolic blood flow velocities in cerebral arteries were detected with trans-cranial Doppler. Key factors, such as anthropometry, life-style, medication use, blood pressure and blood biochemical analysis were investigated at the same time.

RESULTS

In women, even controlled for major cardiovascular risk factors, cerebral blood flow velocities of common carotid artery, internal carotid artery, middle cerebral artery, anterior cerebral artery and posterior cerebral arteries decreased significantly with age (from 43.8 to 39.3, 48.0 to 42.6, 97.7 to 82.8, 79.2 to 69.4 and 44.1 to 39.7 cm/s in the range of 42-73 years old, p < 0.01 for each). In men, however, this inverse trend only existed in common carotid artery (from 45.6 to 41.7 cm/s, p < 0.01). Multivariate regression showed that most established cardiovascular risk factors (e.g. hypertension, hypercholesterolemia, diabetes mellitus and overweight/obesity) were associated with decreased blood flow velocity in the extra-cranial arteries. However, this association was not present (e.g. diabetes and overweight/obesity) or was inversed (e.g. hypertension and hypercholesterolemia) in the intra-cranial arteries.

CONCLUSION

Extra-cranial blood flow velocity is significantly and inversely related to age and cardiovascular risk factors. The relationship between intra-cranial blood flow and risk factors changes and may depend on gender. These finding may have importance in the determination of mechanisms of stroke.

Transcranial color-coded sonography for the detection of middle cerebral artery stenosis

OBJECTIVE

The purpose of this study was to validate the accuracy and criteria of transcranial color-coded sonography (TCCS) in detecting severe middle cerebral artery (MCA) stenosis.

METHODS

One hundred ninety-three patients with acute ischemic cerebrovascular disease who received both TCCS and magnetic resonance angiography (MRA) examinations were evaluated. Middle cerebral artery stenosis assessed by MRA was graded as follows: grade 0, normal to mild (< 50%); grade 1, focal severe stenosis (> or = 50% and stenotic length within the M1 prebifurcation segment); and grade 2, diffuse severe stenosis (> or = 50% and stenotic length greater than the M1 prebifurcation segment). The peak systolic velocity (Vs) and mean velocity (Vm) of bilateral MCAs were obtained by TCCS. Estimates of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for TCCS relative to MRA.

RESULTS

After 46 patients were excluded, 309 MCAs (grade 0, 77.3%; grade 1, 15.5%; and grade 2, 7.1%) were evaluated. The optimal diagnostic accuracy of TCCS for the detection of grade 1 MCA stenosis can be reached if Vs is 140 cm/s or higher or Vm is 90 cm/s or higher (sensitivity, 83.3%; specificity, 91.2%). The optimal diagnostic accuracy of grade 2 MCA stenosis can be obtained if V(s) is lower than 50 cm/s or V(s) is 140 cm/s or higher (sensitivity, 81.8%; specificity, 92.1%). In our study, none of the grade 1 but around half of the grade 2 stenosis showed a low flow velocity pattern.

CONCLUSIONS

Transcranial color-coded sonography is reliable in detecting severe MCA stenosis. Except for high flow velocity, the addition of a low cutoff of normal flow velocity in our criteria not only increases the study sensitivity but also enables the identification of around half of diffuse severe MCA stenosis.

Microembolic Signal Predicts Recurrent Cerebral Ischemic Events in Acute Stroke Patients With Middle Cerebral Artery Stenosis

BACKGROUND AND PURPOSE

Cerebral embolism is a common cause of stroke. Microembolic signals (MES) detected by transcranial Doppler represent ongoing embolisms, but the lack of reliable data about its clinical relevance hinders its widespread use in clinical practice.

METHODS

We prospectively monitored 114 consecutive acute ischemic stroke patients with middle cerebral artery (MCA) stenosis for MES. The signals on digital audio tape were analyzed by an independent observer who was blinded to all other data. All patients were followed-up for the occurrence of recurrent stroke or transient ischemic attack (TIA) in the indexed MCA territory.

RESULTS

MES was detected in 25 (22%) patients. The mean number of MES was 18 (range, 1 to 102). MES were more common in patients with severe stenosis (10/21, 48%) than in those with mild-moderate stenosis (4/26, 15%) (Pearson chi2 P=0.02). During follow-up for a mean of 13.6 months (range, 1 to 32), 12 (12%) patients had further ischemic events (10 strokes and 2 TIAs) in the affected MCA region during follow-up. Among these, 7 (58%) had recurred within 1 month (1 recurred within 1 week, the other 6 patients had recurrences in week 3 or 4 after discharge), 3 within 6 months, 1 within 6 to 12 months, and the remaining 1 recurred after 1 year. The presence of MES was the only predictor of a further ischemic stroke/TIA by Cox regression (adjusted odds ratio, 8.45; 95% CI, 1.69 to 42.22; P=0.01) even after controlling for age, sex, diabetes, hypertension, previous stroke, smoking, and acute treatment.

CONCLUSIONS

In acute stroke patients with MCA stenosis, MES predicts further cerebral ischemia. This procedure should be considered as part of routine investigation and might identify a group of patients who are most likely to benefit from antithrombotic treatment.

Albuminuria is a marker of increasing intracranial and extracranial vascular involvement in Type 2 diabetic Chinese patients

AIMS/HYPOTHESIS

Albuminuria has been reported to be a marker of cardiovascular risk factors and disease morbidity and mortality, but its relationship with intracerebral atherosclerotic disease is less clear. The aim of this study was to investigate the association between albuminuria and intracranial and extracranial vascular involvement in Chinese Type 2 diabetic patients.

METHODS

The anthropometric and fasting biochemical measurements of 966 Type 2 diabetic patients with normoalbuminuria (55.6%), microalbuminuria (27.7%) or macroalbuminuria (16.7%) were compared. The prevalence of microvascular and macrovascular disease and middle cerebral artery (MCA) stenosis, measured by transcranial Doppler ultrasound, were also compared between the groups.

RESULTS

Albuminuria was closely associated with a range of adverse parameters, including high BP, dyslipidaemia, smoking and adiposity (all p<0.01). The prevalence of microvascular disease (retinopathy p<0.001) and macrovascular disease (peripheral vascular disease p=0.012, myocardial infarction, p=0.004, MCA stenosis p<0.001) increased significantly with increasing levels of albuminuria. Albuminuria was also found to be an independent predictor of microvascular and macrovascular disease.

CONCLUSIONS/INTERPRETATION

Albuminuria was an independent predictor of increasing levels of vascular risk factors and microvascular and macrovascular disease in this group of Type 2 diabetic patients, and a possible role for albuminuria as a marker of intracranial cerebrovascular disease should be further investigated.

Increasing severity of cardiovascular risk factors with increasing middle cerebral artery stenotic involvement in type 2 diabetic Chinese patients with asymptomatic cerebrovascular disease

OBJECTIVE

To identify determinants associated with increasing severity of middle cerebral artery (MCA) stenosis in asymptomatic Chinese type 2 diabetic patients with and without MCA stenosis determined using transcranial Doppler. Conventional risk factors contribute to the pathogenesis of ischemic stroke, and differences in the pattern of these may explain the heterogeneity of disease presentation in different populations. In Chinese patients, MCA stenosis is the most commonly identified intracranial vascular lesion.

RESEARCH DESIGN AND METHODS

Anthropometric and fasting biochemical parameters were compared between type 2 diabetic patients with MCA stenosis in one (n = 185) or both (n = 200) vessels and 1,492 type 2 diabetic patients without evidence of stenosis.

RESULTS

Increasing MCA stenotic vascular involvement was associated with significantly increasing age, duration of diabetes, systolic blood pressure, and LDL cholesterol, but with lower glucose levels. There was also an increased prevalence of hypertension, dyslipidemia, and use of blood pressure-and glucose-lowering agents in the patients with MCA stenosis. Concomitant significant increases in the prevalence of peripheral vascular disease and retinopathy were also observed in the patients with MCA stenosis.

CONCLUSIONS

Transcranial Doppler examination identified stenosis in one or both MCAs in over one-fifth of the Chinese type 2 diabetic subjects without symptoms of cerebrovascular disease. A number of conventional cardiovascular risk factors were closely associated with MCA stenosis. This technique may allow the identification of a particularly high-risk group, and further studies are required to determine whether asymptomatic MCA stenosis is predictive of primary cerebrovascular events and whether intensive treatment of risk factors would reduce the risk.

Long-term mortality and recurrent stroke risk among Chinese stroke patients with predominant intracranial atherosclerosis

BACKGROUND AND PURPOSE

The goal of this study was to document the long-term outcome of ischemic stroke patients in a population with predominant intracranial atherosclerosis and risk factors for a recurrent event.

METHODS

Intracranial and extracranial arteries of consecutive patients with acute ischemic stroke were studied prospectively with transcranial Doppler and duplex ultrasound. All patients were followed up regularly for the development of recurrent stroke, cardiac event, or death.

RESULTS

We included 705 patients with acute ischemic stroke, of whom 345 were documented ultrasonographically as having large-artery lesions. The follow-up period was up to 42 months (mean, 28+/-5 months). One hundred seventeen patients (17%) died of any cause, and 199 (28%) suffered further cerebrovascular cardiac events. The 3.5-year cumulative mortality rate was 20.8%; for cerebrovascular event, it was 29.5%. The annual recurrent stroke rates during the first year were 10.9% for patients without vascular lesion, 17.1% for intracranial atherosclerosis only, and 24.3% for both intracranial and extracranial atherosclerosis; for the second year, the rates were 7.5%, 8.6%, and 7.7%, respectively. More occurrence of death (log rank, 5.19; P=0.02) or cerebrovascular event (log rank, 9.68; P=0.002) was found among patients with than those without vascular lesions. Patients with both intracranial and extracranial arterial lesions were at highest risk of death (log rank, 9.64; P=0.008) and cerebrovascular event (log rank, 11.56; P=0.003). When death and further vascular event were combined as poor outcomes in a Cox proportional-hazards regression model, number of abnormal arteries, advanced age, diabetes, atrial fibrillation, and previous stroke were significant predictors.

CONCLUSIONS

Patients with intracranial atherosclerosis, especially coexisting extracranial carotid disease, are at higher risk of suffering death or further vascular event. Our findings provide important data for planning future randomized clinical trials for this high-risk group of stroke patients.