Cerebral Hemodynamics Underlying Artery-to-Artery Embolism in Symptomatic Intracranial Atherosclerotic Disease

Artery-to-artery embolism (AAE) is a common stroke mechanism in intracranial atherosclerotic disease (ICAD), associated with a considerable risk of recurrent stroke. We aimed to investigate cerebral hemodynamic features associated with AAE in symptomatic ICAD. Patients with anterior-circulation, symptomatic ICAD confirmed in CT angiography (CTA) were recruited. We classified probable stroke mechanisms as isolated parent artery atherosclerosis occluding penetrating artery, AAE, hypoperfusion, and mixed mechanisms, largely based on infarct topography. CTA-based computational fluid dynamics (CFD) models were built to simulate blood flow across culprit ICAD lesions. Translesional pressure ratio (PR = Pressurepost-stenotic/Pressurepre-stenotic) and wall shear stress ratio (WSSR = WSSstenotic-throat/WSSpre-stenotic) were calculated, to reflect the relative, translesional changes of the two hemodynamic metrics. Low PR (PR ≤ median) and high WSSR (WSSR ≥ 4th quartile) respectively indicated large translesional pressure and elevated WSS upon the lesion. Among 99 symptomatic ICAD patients, 44 had AAE as a probable stroke mechanism, 13 with AAE alone and 31 with coexisting hypoperfusion. High WSSR was independently associated with AAE (adjusted OR = 3.90; P = 0.022) in multivariate logistic regression. There was significant WSSR-PR interaction on the presence of AAE (P for interaction = 0.013): high WSSR was more likely to associate with AAE in those with low PR (P = 0.075), but not in those with normal PR (P = 0.959). Excessively elevated WSS in ICAD might increase the risk of AAE. Such association was more prominent in those with large translesional pressure gradient. Hypoperfusion, commonly coexisting with AAE, might be a therapeutic indicator for secondary stroke prevention in symptomatic ICAD with AAE.

Clinical Associations and Prognostic Value of MRI-Visible Perivascular Spaces in Patients With Ischemic Stroke or TIA: A Pooled Analysis

BACKGROUND AND OBJECTIVES

Visible perivascular spaces are an MRI marker of cerebral small vessel disease and might predict future stroke. However, results from existing studies vary. We aimed to clarify this through a large collaborative multicenter analysis.

METHODS

We pooled individual patient data from a consortium of prospective cohort studies. Participants had recent ischemic stroke or transient ischemic attack (TIA), underwent baseline MRI, and were followed up for ischemic stroke and symptomatic intracranial hemorrhage (ICH). Perivascular spaces in the basal ganglia (BGPVS) and perivascular spaces in the centrum semiovale (CSOPVS) were rated locally using a validated visual scale. We investigated clinical and radiologic associations cross-sectionally using multinomial logistic regression and prospective associations with ischemic stroke and ICH using Cox regression.

RESULTS

We included 7,778 participants (mean age 70.6 years; 42.7% female) from 16 studies, followed up for a median of 1.44 years. Eighty ICH and 424 ischemic strokes occurred. BGPVS were associated with increasing age, hypertension, previous ischemic stroke, previous ICH, lacunes, cerebral microbleeds, and white matter hyperintensities. CSOPVS showed consistently weaker associations. Prospectively, after adjusting for potential confounders including cerebral microbleeds, increasing BGPVS burden was independently associated with future ischemic stroke (versus 0-10 BGPVS, 11-20 BGPVS: HR 1.19, 95% CI 0.93-1.53; 21+ BGPVS: HR 1.50, 95% CI 1.10-2.06; p = 0.040). Higher BGPVS burden was associated with increased ICH risk in univariable analysis, but not in adjusted analyses. CSOPVS were not significantly associated with either outcome.

DISCUSSION

In patients with ischemic stroke or TIA, increasing BGPVS burden is associated with more severe cerebral small vessel disease and higher ischemic stroke risk. Neither BGPVS nor CSOPVS were independently associated with future ICH.

Association of Alternative Anticoagulation Strategies and Outcomes in Patients With Ischemic Stroke While Taking a Direct Oral Anticoagulant

BACKGROUND AND OBJECTIVES

Ischemic stroke despite a direct oral anticoagulant (DOAC) is increasingly common and portends a high risk of subsequent ischemic stroke. The efficacy and safety of antithrombotic regimens after the condition are unclear. We aimed to compare the outcomes of patients with ischemic stroke despite DOACs with and without an alternative antithrombotic regimen and determine the risk factors of recurrent ischemic stroke while on anticoagulation.

METHODS

In a population-based, propensity score-weighted, retrospective cohort study, we compared the clinical outcomes of DOAC-to-warfarin switch, DOAC-to-DOAC switch (DOACswitch), or addition of antiplatelet agents, with those of unchanged DOAC regimen (DOACsame) among patients with nonvalvular atrial fibrillation (NVAF) who developed the first ischemic stroke despite a DOAC from January 1, 2015, to December 31, 2020, in Hong Kong. The primary outcome was recurrent ischemic stroke. Secondary outcomes were intracranial hemorrhage, acute coronary syndrome, and death. We performed competing risk regression analyses to compare the clinical endpoints and determined the predictors of recurrent ischemic stroke in an unweighted multivariable logistic regression model.

RESULTS

During the 6-year study period, among 45,946 patients with AF on a DOAC as stroke prophylaxis, 2,908 patients developed ischemic stroke despite a DOAC. A total of 2,337 patients with NVAF were included in the final analyses. Compared with DOACsame, warfarin (aHR 1.96, 95% CI 1.27-3.02, p = 0.002) and DOACswitch (aHR 1.62, 95% CI 1.25-2.11, p < 0.001) were associated with an increased risk of recurrent ischemic stroke. In the DOACsame group, adjunctive antiplatelet agent was not associated with a reduced risk of recurrent ischemic stroke. Diabetes mellitus, concurrent cytochrome P450/P-glycoprotein (CYP/P-gp) modulators, and large artery atherosclerotic disease (LAD) were predictors of recurrent ischemic stroke.

DISCUSSION

In patients with NVAF with ischemic stroke despite a DOAC, the increased risk of recurrent ischemic stroke with switching to warfarin called for caution against such practice, while the increased ischemic stroke with DOAC-to-DOAC switch demands further studies. Adjunctive antiplatelet agent did not seem to reduce ischemic stroke relapse. Because diabetes mellitus, the use of CYP/P-gp modulators, and LAD were predictors of recurrent ischemic stroke, further investigations should evaluate whether strict glycemic control, DOAC level monitoring, and routine screening for carotid and intracranial atherosclerosis may reduce ischemic stroke recurrence in these patients.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that in patients with NVAF experiencing an ischemic stroke while being treated with a DOAC, continuing treatment with that DOAC is more effective at preventing recurrent ischemic stroke than switching to a different DOAC or to warfarin.

Stroke Risk and Antithrombotic Treatment During Follow-up of Patients With Ischemic Stroke and Cortical Superficial Siderosis

BACKGROUND AND OBJECTIVES

In patients with ischemic stroke (IS) or transient ischemic attack (TIA) and cortical superficial siderosis (cSS), there are few data regarding the risk of future cerebrovascular events and also about the benefits and safety of antithrombotic drugs for secondary prevention. We investigated the associations of cSS and stroke risk in patients with recent IS or TIA.

METHODS

We retrospectively analyzed the Microbleeds International Collaborative Network (MICON) database. We selected patients with IS or TIA from cohorts who had MRI-assessed cSS, available data on antithrombotic treatments, recurrent cerebrovascular events (intracranial hemorrhage [ICrH], IS, or any stroke [ICrH or IS]), and mortality. We calculated incidence rates (IRs) and performed univariable and multivariable Cox regression analyses.

RESULTS

Of 12,669 patients (mean age 70.4 ± 12.3 years, 57.3% men), cSS was detected in 273 (2.2%) patients. During a mean follow-up of 24 ± 17 months, IS was more frequent than ICrH in both cSS (IR 57.1 vs 14.6 per 1,000 patient-years) and non-cSS (33.7 vs 6.3 per 1,000 patient-years) groups. Compared with the non-cSS group, cSS was associated with any stroke on multivariable analysis {IR 83 vs 42 per 1,000 patient-years, adjusted hazard ratio [HR] for cSS 1.62 (95% CI: 1.14-2.28; p = 0.006)}. This association was not significant in subgroups of patients treated with antiplatelet drugs (n = 6,554) or with anticoagulants (n = 4,044). Patients with cSS who were treated with both antiplatelet drugs and anticoagulants (n = 1,569) had a higher incidence of ICrH (IR 107.5 vs 4.9 per 1,000 patient-years, adjusted HR 13.26; 95% CI: 2.90-60.63; p = 0.001) and of any stroke (IR 198.8 vs 34.7 per 1,000 patient-years, adjusted HR 5.03; 95% CI: 2.03-12.44; p < 0.001) compared with the non-cSS group.

DISCUSSION

Patients with IS or TIA with cSS are at increased risk of stroke (ICrH or IS) during follow-up; the risk of IS exceeds that of ICrH for patients receiving antiplatelet or anticoagulant treatment alone, but the risk of ICrH exceeds that of IS in patients receiving both treatments. The findings suggest that either antiplatelet or anticoagulant treatment alone should not be avoided in patients with cSS, but combined antithrombotic therapy might be hazardous. Our findings need to be confirmed by randomized clinical trials.

Risk stratification in symptomatic intracranial atherosclerotic disease with conventional vascular risk factors and cerebral haemodynamics

BACKGROUND AND PURPOSE

Symptomatic intracranial atherosclerotic stenosis (sICAS) is associated with a considerable risk of recurrent stroke despite contemporarily optimal medical treatment. Severity of luminal stenosis in sICAS and its haemodynamic significance quantified with computational fluid dynamics (CFD) models were associated with the risk of stroke recurrence. We aimed to develop and compare stroke risk prediction nomograms in sICAS, based on vascular risk factors and these metrics.

METHODS

Patients with 50%-99% sICAS confirmed in CT angiography (CTA) were enrolled. Conventional vascular risk factors were collected. Severity of luminal stenosis in sICAS was dichotomised as moderate (50%-69%) and severe (70%-99%). Translesional pressure ratio (PR) and wall shear stress ratio (WSSR) were quantified via CTA-based CFD modelling; the haemodynamic status of sICAS was classified as normal (normal PR&WSSR), intermediate (otherwise) and abnormal (abnormal PR&WSSR). All patients received guideline-recommended medical treatment. We developed and compared performance of nomograms composed of these variables and independent predictors identified in multivariate logistic regression, in predicting the primary outcome, recurrent ischaemic stroke in the same territory (SIT) within 1 year.

RESULTS

Among 245 sICAS patients, 20 (8.2%) had SIT. The D₂H₂A nomogram, incorporating diabetes, dyslipidaemia, haemodynamic status of sICAS, hypertension and age ≥50 years, showed good calibration (P for Hosmer-Lemeshow test=0.560) and discrimination (C-statistic 0.73, 95% CI 0.60 to 0.85). It also had better performance in risk reclassification and provided larger net benefits in decision curve analysis, compared with nomograms composed of conventional vascular risk factors only, and plus the severity of luminal stenosis in sICAS. Sensitivity analysis in patients with anterior-circulation sICAS showed similar results.

CONCLUSIONS

The D₂H₂A nomogram, incorporating conventional vascular risk factors and the haemodynamic significance of sICAS as assessed in CFD models, could be a useful tool to stratify sICAS patients for the risk of recurrent stroke under contemporarily optimal medical treatment.

Effects of stent shape on focal hemodynamics in intracranial atherosclerotic stenosis: A simulation study with computational fluid dynamics modeling

Background and aims

The shape of a stent could influence focal hemodynamics and subsequently plaque growth or in-stent restenosis in intracranial atherosclerotic stenosis (ICAS). In this preliminary study, we aim to investigate the associations between stent shapes and focal hemodynamics in ICAS, using computational fluid dynamics (CFD) simulations with manually manipulated stents of different shapes.

Methods

We built an idealized artery model, and reconstructed four patient-specific models of ICAS. In each model, three variations of stent geometry (i.e., enlarged, inner-narrowed, and outer-narrowed) were developed. We performed static CFD simulation on the idealized model and three patient-specific models, and transient CFD simulation of three cardiac cycles on one patient-specific model. Pressure, wall shear stress (WSS), and low-density lipoprotein (LDL) filtration rate were quantified in the CFD models, and compared between models with an inner- or outer-narrowed stent vs. an enlarged stent. The absolute difference in each hemodynamic parameter was obtained by subtracting values from two models; a normalized difference (ND) was calculated as the ratio of the absolute difference and the value in the enlarged stent model, both area-averaged throughout the arterial wall.

Results

The differences in focal pressure in models with different stent geometry were negligible (ND<1% for all cases). However, there were significant differences in the WSS and LDL filtration rate with different stent geometry, with ND >20% in a static model. Observable differences in WSS and LDL filtration rate mainly appeared in area adjacent to and immediately distal to the stent. In the transient simulation, the LDL filtration rate had milder temporal fluctuations than WSS.

Conclusions

The stent geometry might influence the focal WSS and LDL filtration rate in ICAS, with negligible effect on pressure. Future studies are warranted to verify the relevance of the changes in these hemodynamic parameters in governing plaque growth and possibly in-stent restenosis in ICAS.

Elevated Neutrophil to Lymphocyte Ratio Associated With Increased Risk of Recurrent Vascular Events in Older Minor Stroke or TIA Patients

Background

The risk of recurrent stroke following a minor stroke or transient ischemic attack (TIA) is high, when inflammation might play an important role. We aimed to evaluate the value of neutrophil to lymphocyte ratio (NLR) in predicting composite cardiovascular events in patients with minor stroke and TIA.

Methods

Consecutive patients with acute minor stroke or TIA admitted within 24 h of symptoms onset during a 5-year period in a prospective stroke registry were analyzed. We calculated the NLR dividing absolute neutrophil count by absolute lymphocyte count tested within 24 h of admission. NLR ≥4th quartile was defined as high NLR. A composite outcome was defined as stroke, acute coronary syndrome or vascular death within 1 year. We investigated associations between NLR and the composite outcome in univariate and multivariate analyses, among all patients and in those aged over 60 years (i.e., older patients).

Results

Overall, 841 patients (median age 68 years; 60.4% males) were recruited. No significant independent association was found between NLR and the composite outcome in multivariate analysis in the overall cohort. Among the 612 older patients (median age 73 years; 59.2% males), the median NLR was 2.76 (interquartile range 1.96-4.00) and 148 (24.2%) patients had high NLR. The composite outcome occurred in 77 (12.6%) older patients, who were more likely to have a high NLR (39.0% versus 22.1%; p = 0.001) than those without a composite outcome. In multivariate logistic regression, high NLR (adjusted odds ratio 2.00; 95% confidence interval 1.07-3.75; p = 0.031) was independently associated with the composite outcome in older patients.

Conclusion

In older (aged ≥60 years) patients with acute minor stroke or TIA, a higher NLR, a marker of systemic inflammation that can be easily obtained in routine blood tests, is an independent predictor of subsequent cardiovascular events.

Effects of wearable ankle robotics for stair and over-ground training on sub-acute stroke: a randomized controlled trial

BACKGROUND

Wearable ankle robotics could potentially facilitate intensive repetitive task-specific gait training on stair environment for stroke rehabilitation. A lightweight (0.5 kg) and portable exoskeleton ankle robot was designed to facilitate over-ground and stair training either providing active assistance to move paretic ankle augmenting residual motor function (power-assisted ankle robot, PAAR), or passively support dropped foot by lock/release ankle joint for foot clearance in swing phase (swing-controlled ankle robot, SCAR). In this two-center randomized controlled trial, we hypothesized that conventional training integrated with robot-assisted gait training using either PAAR or SCAR in stair environment are more effective to enhance gait recovery and promote independency in early stroke, than conventional training alone.

METHODS

Sub-acute stroke survivors (within 2 months after stroke onset) received conventional training integrated with 20-session robot-assisted training (at least twice weekly, 30-min per session) on over-ground and stair environments, wearing PAAR (n = 14) or SCAR (n = 16), as compared to control group receiving conventional training only (CT, n = 17). Clinical assessments were performed before and after the 20-session intervention, including functional ambulatory category as primary outcome measure, along with Berg balance scale and timed 10-m walk test.

RESULTS

After the 20-session interventions, all three groups showed statistically significant and clinically meaningful within-group functional improvement in all outcome measures (p < 0.005). Between-group comparison showed SCAR had greater improvement in functional ambulatory category (mean difference + 0.6, medium effect size 0.610) with more than 56% independent walkers after training, as compared to only 29% for CT. Analysis of covariance results showed PAAR had greater improvement in walking speed than SCAR (mean difference + 0.15 m/s, large effect size 0.752), which was in line with the higher cadence and speed when wearing the robot during the 20-session robot-assisted training over-ground and on stairs.

CONCLUSIONS

Robot-assisted stair training would lead to greater functional improvement in gait independency and walking speed than conventional training in usual care. The active powered ankle assistance might facilitate users to walk more and faster with their paretic leg during stair and over-ground walking.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03184259. Registered on 12 June 2017.

Intracranial Atherosclerosis Coexisting With White Matter Hyperintensities May Predict Unfavorable Functional Outcome in Patients With Acute Cerebral Ischemia

Background and Purpose: This study aimed to assess the effect of baseline white matter hyperintensities (WMH) on 1-year stroke recurrence and the functional outcome for patients with intracranial atherosclerosis (ICAS).

Methods: We analyzed 2,076 patients who were enrolled in the Chinese IntraCranial AtheroSclerosis (CICAS) study. ICAS and WMH were diagnosed by baseline magnetic resonance angiography. The primary outcomes were stroke recurrence and unfavorable functional outcome (modified Rankin Scale score 3–6) at 1 year.

Results: Of the 2,076 patients included in this study, 1,370 (65.99%) were men, and the mean age was 61.70 years. In total, 224 (10.79%) patients had no WMH and no ICAS, 922 (44.41%) patients had WMH and no ICAS, 157 (7.56%) patients had ICAS and no WMH, and 773 (37.24%) had both WMH and ICAS. During the follow-up period, 87 patients had a recurrent stroke and 333 had unfavorable outcomes at 1 year. Compared to WMH (–) ICAS (–) group, the adjusted odd ratios and 95% confidence interval for unfavorable functional outcome were 0.791 (0.470–1.332; p = 0.3779) in the WMH (+) ICAS (–) group, 1.920 (1.024–3.600; p = 0.0421) in the WMH (–) ICAS (+) group, and 2.046 (1.230–3.403; p = 0.0058) in the WMH (+) ICAS (+) group. There was no significant difference in stroke recurrence risk among the four groups.

Conclusion: ICAS coexisting with WMH may predict an unfavorable functional outcome at 1 year, but not stroke recurrence.

Hemodynamic Significance of Middle Cerebral Artery Stenosis Associated With the Severity of Ipsilateral White Matter Changes

Background: Previous studies conflicted in the association between intracranial atherosclerotic stenosis (ICAS) and the severity of white matter changes (WMC).

Aims: We aimed to investigate the relationships between the severity of luminal stenosis and the hemodynamic significance of middle cerebral artery (MCA) stenosis, and the severity of ipsilateral WMC.

Methods: In this cross-sectional study, patients with a recent ischemic stroke or transient ischemic attack and a 50–99% MCA-M1 stenosis in the Chinese Intracranial Atherosclerosis study cohort were analyzed. The post- to pre-stenotic signal intensity ratio (SIR) was obtained in time-of-flight MR angiography (MRA) to represent the hemodynamic significance of MCA-M1 stenosis, with a lower SIR indicating a hemodynamically more severe lesion. The severity of ipsilesional WMC was assessed by an age-related WMC (ARWMC) scale in T2-weighted fluid attenuated inversion recovery MR imaging. The relationships between the degree of MCA-M1 stenosis, SIR, and ipsilesional ARWMC scale were analyzed. The MCA-M1 lesion with a higher percentage of stenosis was chosen for analyses in patients with bilateral MCA-M1 stenoses.

Results: Among 180 subjects (mean age, 64 years), a lower SIR of MCA-M1 stenosis (Spearman correlation coefficient, −0.543; p < 0.001), but not the degree of stenosis (p = 0.93), was significantly linearly correlated with a higher ipsilateral ARWMC. Multivariate ordinal logistic regression identified older age (OR = 1.037; 95% CI, 1.008–1.066; p = 0.011) and lower SIR (OR = 0.010; 95% CI, 0.002–0.058; p < 0.001) as independent predictors for more severe ipsilateral WMC.

Conclusion: Patients with hemodynamically more severe ICAS are more likely to have more severe ipsilateral WMC. Longitudinal studies with sequential imaging exams may further reveal the impact of hemodynamic significance of ICAS on the development and progression of WMC.

Translesional Pressure Gradient Alters Relationship Between Blood Pressure and Recurrent Stroke in Intracranial Stenosis

Background and Purpose- There is debate over an optimal systolic blood pressure (SBP) in secondary stroke prevention of patients with symptomatic intracranial atherosclerotic stenosis (sICAS). We investigated whether translesional pressure gradient across sICAS would alter the relationship between SBP and risk of recurrent stroke in such patients. Methods- We recruited patients with sICAS (50%-99% stenosis) confirmed in computed tomography angiography. We simulated blood flow across sICAS with computed tomography angiography-based computational fluid dynamics models. Translesional pressure ratio (PR=Pressure_{post-stenotic}/Pressure_pre-stenotic) was calculated in each case. Pressure ratio (PR) ≤ median was defined as low PR, indicating larger translesional pressure gradient across sICAS. All patients received optimal medical treatment. We investigated the interaction of translesional PR and mean SBP during follow-up (SBP_FU) in determining the risk of the primary outcome, recurrent ischemic stroke in the same territory within 1 year. Results- Among 157 patients with sICAS, the median PR was 0.93. Multivariate Cox regression revealed significant PR-SBP_FU interaction on the primary outcome (P=0.008): in patients with normal PR, risk of primary outcome significantly decreased with lower SBP_FU (hazard ratio for 10 mm Hg decrement =0.46; P=0.018); however, in those with low PR, SBP_FU≤130 mm Hg was associated with significantly increased risk of primary outcome, compared with 130<SBP_FU<150 mm Hg (hazard ratio=5.08; P=0.043). Conclusions- Low SBP level may be associated with increased risk of stroke recurrence in patients with sICAS with a large translesional pressure gradient. Translesional PR by computational fluid dynamics models may yield a promising indicator to guide more individualized blood pressure management in patients with sICAS, warranting future studies.

Hemodynamics and stroke risk in intracranial atherosclerotic disease

OBJECTIVE

To investigate whether hemodynamic features of symptomatic intracranial atherosclerotic stenosis (sICAS) might correlate with the risk of stroke relapse, using a computational fluid dynamics (CFD) model.

METHODS

In a cohort study, we recruited patients with acute ischemic stroke attributed to 50 to 99% ICAS confirmed by computed tomographic angiography (CTA). With CTA-based CFD models, translesional pressure ratio (PR = pressure_poststenotic /pressure_prestenotic ) and translesional wall shear stress ratio (WSSR = WSS_{stenotic - throat} /WSS_prestenotic ) were obtained in each sICAS lesion. Translesional PR ≤ median was defined as low PR and WSSR ≥4th quartile as high WSSR. All patients received standard medical treatment. The primary outcome was recurrent ischemic stroke in the same territory (SIT) within 1 year.

RESULTS

Overall, 245 patients (median age = 61 years, 63.7% males) were analyzed. Median translesional PR was 0.94 (interquartile range [IQR] = 0.87-0.97); median translesional WSSR was 13.3 (IQR = 7.0-26.7). SIT occurred in 20 (8.2%) patients, mostly with multiple infarcts in the border zone and/or cortical regions. In multivariate Cox regression, low PR (adjusted hazard ratio [HR] = 3.16, p = 0.026) and high WSSR (adjusted HR = 3.05, p = 0.014) were independently associated with SIT. Patients with both low PR and high WSSR had significantly higher risk of SIT than those with normal PR and WSSR (risk = 17.5% vs 3.0%, adjusted HR = 7.52, p = 0.004).

INTERPRETATION

This work represents a step forward in utilizing computational flow simulation techniques in studying intracranial atherosclerotic disease. It reveals a hemodynamic pattern of sICAS that is more prone to stroke relapse, and supports hypoperfusion and artery-to-artery embolism as common mechanisms of ischemic stroke in such patients. Ann Neurol 2019;85:752-764.

Validity and reliability of two alternate versions of the Montreal Cognitive Assessment (Hong Kong version) for screening of Mild Neurocognitive Disorder

Objective

Repeated testing using the Montreal Cognitive Assessment (MoCA) increases risks for practice effects which may bias measurements of cognitive change. The objective of this study is to develop two alternate versions of the MoCA (Hong Kong version; HK-MoCA) and to investigate the validity and reliability of the alternate versions in patients with DSM-5 Mild Neurocognitive Disorder (Mild NCD) and cognitively healthy controls.

Methods

Concurrent validity and inter-scale agreement were examined by Pearson correlation of the total scores between the original and alternate versions and the Bland-Altman Method. Criterion validity of the two alternate versions in differentiating patients with Mild NCD was tested using receiver operating characteristic curve (ROC) analysis. One-month test-retest and inter-rater reliability were examined in 20 participants. Internal consistency of the alternate versions was measured by the Cronbach’s α.

Results

30 controls (age 73.4 [4.5] years, 60% female) and 30 patients (age 75.4 [5.5] years, 73% female) with Mild NCD were recruited. Both alternate versions significantly correlated with the original version (r = 0.79–0.87, p<0.001). Mean differences of 0.17 and -0.40 points were found between the total scores of the alternate with the original versions with a consistent level of agreement observed throughout the range of cognitive abilities. Both alternate versions significantly differentiated patients with Mild NCD from healthy controls (area under ROC 0.922 and 0.724, p<0.001) and showed good one-month test-retest reliability (intra-class correlation [ICC] = 0.92 and 0.82) and inter-rater reliability (ICC = 0.99 and 0.87) and high internal consistency (Cronbach α = 0.79 and 0.75).

Conclusion

The two alternate versions of the HK-MoCA are useful for Mild NCD screening.

Converting MMSE to MoCA and MoCA 5-minute protocol in an educationally heterogeneous sample with stroke or transient ischemic attack

BACKGROUND

The Montreal Cognitive Assessment (MoCA) is psychometrically superior over the Mini-mental State Examination (MMSE) for cognitive screening in stroke or transient ischemic attack (TIA). It is free for clinical and research use. The objective of this study is to convert scores from the MMSE to MoCA and MoCA-5-minute protocol (MoCA-5 min) and to examine the ability of the converted scores in detecting cognitive impairment after stroke or TIA.

METHODS

A total of 904 patients were randomly divided into training (n = 623) and validation (n = 281) samples matched for demography and cognition. MMSE scores were converted to MoCA and MoCA-5 min using (1) equipercentile method with log-linear smoothing and (2) Poisson regression adjusting for age and education. Receiver operating characteristics curve analysis was used to examine the ability of the converted scores in differentiating patients with cognitive impairment.

RESULTS

The mean education was 5.8 (SD = 4.6; ranged 0-20) years. The entire spectrum of MMSE scores was converted to MoCA and MoCA-5 min using equipercentile method. Relationship between MMSE and MoCA scores was confounded by age and education, and a conversion equation with adjustment for age and education was derived. In the validation sample, the converted scores differentiated cognitively impaired patients with area under receiver operating characteristics curve 0.826 to 0.859.

CONCLUSION

We provided 2 methods to convert scores from the MMSE to MoCA and MoCA-5 min based on a large sample of patients with stroke or TIA having a wide range of education and cognitive levels. The converted scores differentiated patients with cognitive impairment after stroke or TIA with high accuracy.

Translesional pressure gradient and leptomeningeal collateral status in symptomatic middle cerebral artery stenosis

BACKGROUND AND PURPOSE

Leptomeningeal collateral (LMC) status governs the prognosis of large artery occlusive stroke, although factors determining LMC status are not fully elucidated. The aim was to investigate metrics affecting LMC status in such patients by using computational fluid dynamics (CFD) models based on computed tomography angiography (CTA).

METHODS

In this cross-sectional study, patients with recent ischaemic stroke or transient ischaemic attack attributed to atherosclerotic M1 middle cerebral artery (MCA) stenosis (50%-99%) were recruited. Demographic, clinical and imaging data of these patients were collected. Ipsilesional LMC status was graded as good or poor by assessing the laterality of anterior and posterior cerebral arteries in CTA. A CFD model based on CTA was constructed to reflect focal hemodynamics in the distal internal carotid artery, M1 MCA and A1 anterior cerebral artery. Pressure gradients were calculated across culprit MCA stenotic lesions in CFD models. Predictors for good LMC status were sought in univariate and multivariate analyses.

RESULTS

Amongst the 85 patients enrolled (mean age 61.5 ± 10.9 years), 38 (44.7%) had good ipsilesional LMC status. The mean pressure gradient across MCA lesions was 14.8 ± 18.1 mmHg. Advanced age (P = 0.030) and a larger translesional pressure gradient (P = 0.029) independently predicted good LMCs. A lower fasting blood glucose level also showed a trend for good LMCs (P = 0.058).

CONCLUSIONS

Our study suggested a correlation between translesional pressure gradient and maturation of LMCs in intracranial atherosclerotic disease. Further studies with more exquisite and dynamic monitoring of cerebral hemodynamics and LMC evolution are needed to verify the current findings.

Autonomic Dysfunction Predicts Clinical Outcomes After Acute Ischemic Stroke: A Prospective Observational Study

BACKGROUND AND PURPOSE

Central autonomic dysfunction increases stroke morbidity and mortality. We aimed to investigate whether poststroke autonomic dysfunction graded by Ewing battery can predict clinical outcome.

METHODS

In this prospective observational study, we assessed autonomic function of ischemic stroke patients within 7 days from symptom onset by Ewing battery. On the basis of the magnitude of autonomic dysfunction, we stratified patients into significant (definite, severe, or atypical) or minor (normal or early) autonomic function impairment groups and correlated the impairment with the 3-month modified Rankin Scale score (good outcome: modified Rankin Scale score 0≈2; poor outcome: modified Rankin Scale score 3≈6).

RESULTS

Among the 150 patients enrolled (mean age, 66.4±9.9 years; 70.7% males), minor autonomic dysfunction was identified in 36 patients (24.0%), and significant autonomic dysfunction was identified in 114 patients (76.0%) based on Ewing battery. In 3 months, a poor functional outcome was found in 32.5% of significant group patients compared with 13.9% in the minor group (P=0.031). Crude odds ratios of the magnitude of autonomic dysfunction and 3-month unfavorable functional outcome after acute ischemic stroke were 2.979 (95% confidence interval, 1.071-8.284; P=0.036). After adjusting for confounding variables with statistical significance between the 2 functional outcome subgroups identified in univariate analysis (including sex and National Institutes of Health Stroke Scale score on admission), the magnitude of autonomic dysfunction still independently predicted an unfavorable outcome, with an odds ratio of 3.263 (95% confidence interval, 1.141-9.335; P=0.027).

CONCLUSIONS

Autonomic dysfunction gauged by Ewing battery predicts poor functional outcome after acute ischemic stroke.

Sex Differences Do Not Exist in Outcomes among Stroke Patients with Intracranial Atherosclerosis in China: Subgroup Analysis from the Chinese Intracranial Atherosclerosis Study

BACKGROUND

To date, sex difference in outcomes among patients with intracranial atherosclerosis (ICAS) has rarely been discussed in China as well as in the world. This study aimed to estimate the sex difference in outcomes among patients with ICAS in Chinese cerebral ischemia patients.

METHODS

We analyzed 1,335 men and women with ICAS who were enrolled in the Chinese Intracranial Atherosclerosis study. They were followed-up for ischemic stroke recurrence, any cause of death, cerebral vascular events (including transient ischemic attack, ischemic and hemorrhagic stroke), combined end points (including cerebral vascular events, angina or myocardial infarction, pulmonary embolism, peripheral vascular events), and unfavorable outcome (modified Rankin scale score of 3-6) at 1 year.

RESULTS

During the follow-up period, 59 (13.44%) combined end points were documented in women and 107 (11.94%) in men. Of the combined end points, 47 were recurrent ischemic stroke events (14 in women and 33 in men), and 51 other causes of deaths (24 in women and 27 in men). There were 349 unfavorable end points (117 in women and 232 in men). The cumulative probability of death was higher in women, but after adjusting for age, diabetes mellitus, hypertension, family history of stroke, current smoker, heavy drinking, hyperhomocysteinemia, and heart disease, there was no significant difference. There was also a lack of difference in 1-year ischemic stroke recurrence, cerebral vascular events, combined end points, and unfavorable outcome between women and men at 1 year.

CONCLUSIONS

These results suggest no sex difference in outcome among patients with ICAS in Chinese cerebral ischemia patients.

The prognosis of acute symptomatic seizures after ischaemic stroke

OBJECTIVE

Acute symptomatic seizure (AS) after ischaemic stroke is defined as a seizure occurring ≤7 days of the stroke. There remains a lack of information on the prognosis of AS after ischaemic stroke and how it should be treated.

METHODS

We prospectively recruited patients after their incidents of ischaemic stroke from a population-based stroke registry. Stroke aetiology was defined according to Trial-of-ORG-10172 in acute-stroke treatment (TOAST). Patients were examined for any transient complete-occlusion with recanalisation (TCOR) and haemorrhagic transformation. The seizure outcomes were (1) acute clustering of seizures ≤7 days, (2) seizure recurrence associated with stroke recurrence beyond the 7-day period and (3) unprovoked seizure (US) >7 days.

RESULTS

104 patients (mean age 65 years/55% female) with AS after ischaemic stroke were identified (mean follow-up 6.17 years). Comparison of the group of patients with AS and those without seizures showed that patients with AS had significantly less large-vessel and small-vessel disease but more cardioembolisms (p<0.05) and a higher proportion of TCOR (p<0.01), multiple territory infarcts (p=0.007) and haemorrhagic transformations (p<0.01). Using Kaplan-Meier statistics, the risk of acute clustering of seizures ≤7 days was 22%, with a statistical trend for TCOR as a predictive factor (p=0.06). The risk of seizure recurrence associated with worsening/recurrence of stroke beyond 7 days was 13.5% at 2 years, 16.4% at 4 years and 18% at 8 years. Presence of >2 cardiovascular risk factors (p<0.05) and status epilepticus (P<0.05) are predictive risk factors on Cox regression model. The risk of US was 19% at 2 years, 25% at 4 years and 28% at 8 years with epileptiform EEG as a predictive factor (p<0.05).

CONCLUSIONS

Seizure recurrence following AS after ischaemic stroke may appear as acute clustering. Afterwards, seizures may occur as often with a recurrent stroke as without one within 4.2 years. We recommend the use of antiepileptic agents for up to 4 years if the underlying stroke aetiology cannot be fully treated.

Neuropsychiatric Symptom Clusters in Stroke and Transient Ischemic Attack by Cognitive Status and Stroke Subtype: Frequency and Relationships with Vascular Lesions, Brain Atrophy and Amyloid

Background

The objectives of this study are 1) to examine the frequencies of neuropsychiatric symptom clusters in patients with stroke or transient ischemic attack (TIA) by cognitive level and stroke subtype; and 2) to evaluate effect of demographic, clinical, and neuroimaging measures of chronic brain changes and amyloid upon neuropsychiatric symptom clusters.

Methods

Hospital-based, cross-sectional study. 518 patients were administered the Neuropsychiatric Inventory (NPI) 3–6 months post index admission. NPI symptoms were classified into four symptom clusters (Behavioral Problems, Psychosis, Mood Disturbance & Euphoria) derived from a confirmatory factor analysis of the 12 NPI items. Multivariable logistic regression was used to determine independent associations between demographic, clinical and neuroimaging measures of chronic brain changes (white matter changes, old infarcts, whole brain atrophy, medial temporal lobe atrophy [MTLA] and frontal lobe atrophy [FLA]) with the presence of NPI symptoms and all symptom clusters except euphoria. ¹¹C-Pittsburg Compound B Positron Emission Tomography (¹¹C-PiB PET) was performed in 24 patients to measure amyloid retention for Alzheimer’s Disease (AD) pathology.

Results

50.6% of the whole sample, including 28.7% cognitively normal and 66.7% of patients with mild cognitive symptoms, had ≥1 NPI symptoms. Frequencies of symptom clusters were largely similar between stroke subtypes. Compared to patients with cardioembolic stroke and intracranial haemorrhage, those with TIA had less frequent mood disturbance. Stroke severity at admission and MTLA were the most robust correlates of symptoms. FLA was associated with behavioral problems cluster only. Frequency of symptom clusters did not differ between patients with and without significant amyloid retention.

Conclusion

Frequency of neuropsychiatric symptoms increased with level of cognitive impairment but was largely similar between stroke subtypes. Stroke severity and MTLA were associated with neuropsychiatric symptoms. AD pathology appeared to be unrelated to neuropsychiatric manifestations but further studies with larger sample size are required to substantiate this finding.

Delayed-onset dementia after stroke or transient ischemic attack

INTRODUCTION

Patients surviving stroke without immediate dementia are at high risk of delayed-onset dementia. Mechanisms underlying delayed-onset dementia are complex and may involve vascular and/or neurodegenerative diseases.

METHODS

Dementia-free patients with stroke and/or transient ischemic attack (TIA; n = 919) were studied for 3 years prospectively, excluding those who developed dementia 3 to 6 months after stroke and/or TIA.

RESULTS

Forty subjects (4.4%) developed dementia during the study period. Imaging markers of severe small vessel disease (SVD), namely presence of ≥3 lacunes and confluent white matter changes; history of hypertension and diabetes mellitus independently predicted delayed-onset dementia after adjustment for age, gender, and education. Only 6 of 31 (19.4%) subjects with delayed cognitive decline harbored Alzheimer's disease-like Pittsburg compound B (PiB) retention. Most PiB cases (16/25, 64%) had evidence of severe SVD.

DISCUSSION

Severe SVD contributes importantly to delayed-onset dementia after stroke and/or TIA. Future clinical trials aiming to prevent delayed-onset dementia after stroke and/or TIA should target this high-risk group.

Diminished Signal Intensities Distal to Intracranial Arterial Stenosis on Time-of-Flight MR Angiography Might Indicate Delayed Cerebral Perfusion

BACKGROUND

Intracranial arterial stenosis (ICAS) is a predominant cause of ischemic stroke in Asia. Changes in the signal intensities (SIs) across ICAS lesions on time-of-flight magnetic resonance angiography (TOF-MRA) have been indicated to partially reflect the hemodynamic significance of the lesions, which we aimed to verify by correlating it with cerebral perfusion features provided by CT perfusion (CTP) imaging.

METHODS

Ischemic stroke or transient ischemic attack patients with unilateral symptomatic stenosis (≥50%) of intracranial internal carotid artery or middle cerebral artery (MCA) were included in this study. Change of SIs across an ICAS lesion on TOF-MRA was calculated by the distal and proximal SI ratio (SIR). Cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) within the MCA territory of ipsilateral and contralateral hemispheres were evaluated on the CTP images at the basal ganglia level. Relative CBV, CBF and MTT were defined as ratios of the values obtained from ipsilateral and contralateral hemispheres. The relationships between SIR and CTP parameters were analyzed.

RESULTS

Fifty subjects (74% male, mean age 62) were recruited. Overall, the mean SIR was 0.77 ± 0.17. SIR of ICAS was significantly, linearly and negatively correlated with ipsilateral CBV (r = -0.335, p = 0.017), ipsilateral MTT (r = -0.301, p = 0.034), and ipsilateral/contralateral MTT ratio (r = -0.443, p = 0.001).

CONCLUSIONS

Diminished SIs distal to ICAS on TOF-MRA might be associated with delayed ipsilateral cerebral perfusion. Changes of the SIs across ICAS lesions on TOF-MRA may be a simple marker to reflect cerebral perfusion changes in patients with symptomatic ICAS.

Computational fluid dynamics modeling of symptomatic intracranial atherosclerosis may predict risk of stroke recurrence

BACKGROUND

Patients with symptomatic intracranial atherosclerosis (ICAS) of ≥ 70% luminal stenosis are at high risk of stroke recurrence. We aimed to evaluate the relationships between hemodynamics of ICAS revealed by computational fluid dynamics (CFD) models and risk of stroke recurrence in this patient subset.

METHODS

Patients with a symptomatic ICAS lesion of 70-99% luminal stenosis were screened and enrolled in this study. CFD models were reconstructed based on baseline computed tomographic angiography (CTA) source images, to reveal hemodynamics of the qualifying symptomatic ICAS lesions. Change of pressures across a lesion was represented by the ratio of post- and pre-stenotic pressures. Change of shear strain rates (SSR) across a lesion was represented by the ratio of SSRs at the stenotic throat and proximal normal vessel segment, similar for the change of flow velocities. Patients were followed up for 1 year.

RESULTS

Overall, 32 patients (median age 65; 59.4% males) were recruited. The median pressure, SSR and velocity ratios for the ICAS lesions were 0.40 (-2.46-0.79), 4.5 (2.2-20.6), and 7.4 (5.2-12.5), respectively. SSR ratio (hazard ratio [HR] 1.027; 95% confidence interval [CI], 1.004-1.051; P = 0.023) and velocity ratio (HR 1.029; 95% CI, 1.002-1.056; P = 0.035) were significantly related to recurrent territorial ischemic stroke within 1 year by univariate Cox regression, respectively with the c-statistics of 0.776 (95% CI, 0.594-0.903; P = 0.014) and 0.776 (95% CI, 0.594-0.903; P = 0.002) in receiver operating characteristic analysis.

CONCLUSIONS

Hemodynamics of ICAS on CFD models reconstructed from routinely obtained CTA images may predict subsequent stroke recurrence in patients with a symptomatic ICAS lesion of 70-99% luminal stenosis.

Evaluation of carotid angioplasty and stenting for radiation-induced carotid stenosis

BACKGROUND AND PURPOSE

We aimed to evaluate the procedural safety, clinical, and angiographic outcome of carotid angioplasty and stenting for high-grade (≥70%) radiation-induced carotid stenosis (RIS) using atherosclerotic stenosis (AS) as a control.

METHODS

In this 6-year prospective nonrandomized study, we compared the carotid angioplasty and stenting outcome of 65 consecutive patients (84 vessels) with RIS with that of a control group of 129 consecutive patients (150 vessels) with AS. Study end points were 30-day periprocedural stroke or death, ipsilateral ischemic stroke, technical success, procedural characteristics, instent restenosis (ISR; ≥50%) and symptomatic ISR.

RESULTS

The median follow-up was 47.3 months (95% confidence interval, 26.9-61.6). Imaging assessment was available in 74 vessels (RIS) and 120 vessels (AS) in 2 years. Comparing RIS group with AS group, the rates of periprocedural stroke or death were 1.5% (1/65) versus 1.6% (2/129; P=1); ipsilateral ischemic stroke rates were 4.6% (3/65) versus 4.7% (6/129; P=1); the annual risks of ipsilateral ischemic stroke were 1.2% (3 patient/254.7 patient year) versus 1.2% (6 patient/494.2 patient year; P=0.89); technical success rates were both 100%. Stenting of common carotid artery and the use of multiple stents was more common in the RIS group (P=0 in both cases); ISR rates were 25.7% (19/74) versus 4.2% (5/120; P<0.001); symptomatic ISR rates were 6.8% (5/74) versus 0.8% (1/120; P=0.031).

CONCLUSIONS

The safety, effectiveness, and technical difficulty of carotid angioplasty and stenting for RIS are comparable with that for AS although it is associated with a higher rate of ISR.

CLINICAL TRIAL REGISTRATION

This trial was not registered as enrollment started in 2006.

Prevalence and outcomes of symptomatic intracranial large artery stenoses and occlusions in China: the Chinese Intracranial Atherosclerosis (CICAS) Study

BACKGROUND AND PURPOSE

We aimed to establish the prevalence, characteristics, and outcomes of intracranial atherosclerosis (ICAS) in China by a large, prospective, multicenter study.

METHODS

We evaluated 2864 consecutive patients who experienced an acute cerebral ischemia<7 days after symptom onset in 22 Chinese hospitals. All patients underwent magnetic resonance angiography, with measurement of diameter of the main intracranial arteries. ICAS was defined as ≥50% diameter reduction on magnetic resonance angiography.

RESULTS

The prevalence of ICAS was 46.6% (1335 patients, including 261 patients with coexisting extracranial carotid stenosis). Patients with ICAS had more severe stroke at admission and stayed longer in hospitals compared with those without intracranial stenosis (median National Institutes of Health Stroke Scale score, 3 versus 5; median length of stay, 14 versus 16 days; both P<0.0001). After 12 months, recurrent stroke occurred in 3.27% of patients with no stenosis, in 3.82% for those with 50% to 69% stenosis, in 5.16% for those with 70% to 99% stenosis, and in 7.27% for those with total occlusion. Cox proportional hazards regression analyses showed that the degree of arterial stenosis, age, family history of stroke, history of cerebral ischemia or heart disease, complete circle of Willis, and National Institutes of Health Stroke Scale score at admission were independent predictors for recurrent stroke at 1 year. The highest rate of recurrence was observed in patients with occlusion with the presence of ≥3 additional risk factors.

CONCLUSIONS

ICAS is the most common vascular lesion in patients with cerebrovascular disease in China. Recurrent stroke rate in our study was lower compared with those of previous clinical trials but remains unacceptably high in a subgroup of patients with severe stenosis.

Angiographic features, collaterals, and infarct topography of symptomatic occlusive radiation vasculopathy: a case-referent study

BACKGROUND AND PURPOSE

Occlusive radiation vasculopathy (ORV) predisposes head-and-neck cancer survivors to ischemic strokes.

METHODS

We analyzed the digital subtraction angiography acquired in 96 patients who had first-ever transient ischemic attack or ischemic strokes attributed to ORV. Another age-matched 115 patients who had no radiotherapy but symptomatic high-grade (>70%) carotid stenoses were enrolled as referent subjects. Digital subtraction angiography was performed within 2 months from stroke onset and delineated carotid and vertebrobasilar circulations from aortic arch up to intracranial branches. Two reviewers blinded to group assignment recorded all vascular lesions, collateral status, and infarct pattern.

RESULTS

ORV patients had less atherosclerotic risk factors at presentation. In referent patients, high-grade stenoses were mostly focal at the proximal internal carotid artery. In contrast, high-grade ORV lesions diffusely involved the common carotid artery and internal carotid artery and were more frequently bilateral (54% versus 22%), tandem (23% versus 10%), associated with complete occlusion in one or both carotid arteries (30% versus 9%), vertebral artery (VA) steno-occlusions (28% versus 16%), and external carotid artery stenosis (19% versus 5%) (all P<0.05). With comparable rates of vascular anomaly, ORV patients showed more established collateral circulations through leptomeningeal arteries, anterior communicating artery, posterior communicating artery, suboccipital/costocervical artery, and retrograde flow in ophthalmic artery. In terms of infarct topography, the frequencies of cortical or subcortical watershed infarcts were similar in both groups.

CONCLUSIONS

ORV angiographic features and corresponding collaterals are distinct from atherosclerotic patterns at initial stroke presentation. Clinical decompensation, despite more extensive collateralization, may precipitate stroke in ORV.

Comprehensive assessment for autonomic dysfunction in different phases after ischemic stroke

BACKGROUND AND PURPOSE

Studies mostly use the analysis of heart rate variability to measure cardiovascular autonomic regulation in ischemic stroke. Besides power spectral analysis of heart rate variability, this study sought to determine whether autonomic function was impaired during different phases in ischemic stroke by Ewing's battery of autonomic function tests.

METHODS

Ninety-four patients with ischemic stroke (34 patients in acute phase and 60 patients in chronic phase, average six-months after stroke onset) and thirty-seven elderly controls were recruited. Ewing's battery autonomic function tests and power spectral analysis of heart rate variability were performed in all the subjects.

RESULTS

From power spectral analysis of heart rate variability, stroke patients of both acute and chronic phases had significantly lower low frequency power spectral density than controls. From Ewing's battery of autonomic function tests, patients in acute phase showed impairment in two parasympathetic tests (Valsalva ratio: P = 0·002; heart rate response to deep breathing: P < 0·001) and those in chronic phase showed impairment in all parasympathetic tests (all P < 0·05) in comparison with controls.

CONCLUSIONS

The comprehensive assessment indicates that autonomic dysfunction occurs in acute phase of ischemic stroke and may persist up to six-months after stroke. Parasympathetic dysfunction rather than sympathetic dysfunction is predominant after ischemic stroke.

Risk of intracerebral hemorrhage in patients with cerebral microbleeds undergoing endovascular intervention

BACKGROUND AND PURPOSE

Cerebral microbleeds (CMBs) on MRI gradient echo images are hemosiderin deposits, which may predict intracerebral hemorrhage (ICH). The risk of ICH in patients with CMBs could be exacerbated by the use of antithrombotics. The purpose of our study is to prospectively evaluate the risk of ICH in patients with ischemic stroke who receive dual antiplatelet therapy for endovascular intervention.

METHODS

We analyzed MRI of 133 patients admitted consecutively for intra- and extracranial stenting for symptomatic large artery atherosclerosis who received aspirin and clopidogrel. Quantity and location of CMBs were recorded by neuroradiologists independent from the angioplasty team. The primary end point was symptomatic ICH as evident in CT of the brain within 12 weeks of procedure.

RESULTS

CMBs were identified in 23 patients. Mean number of CMBs was 2.3 ± 1.6. Four patients had >5 CMBs. Forty-seven patients had intracranial stents, 84 patients had extracranial stents, and 2 patients had both intracranial and extracranial stents. There was no difference in risk of symptomatic ICH between those with (4.3%) and without CMBs (5.5%) patient with CMBs (P=1.000).

CONCLUSIONS

The presence of a small number of CMBs does not cause a large increase in the short-term risk of symptomatic ICH in patients with ischemic stroke who undergo endovascular intervention with dual antiplatelet therapy. The risk of ICH in patients with ≥ 5 CMBs, however, remains unclear. Further studies with a larger sample size of patients with multiple CMBs are needed.

Is stroke thrombolysis safe and efficacious in Hong Kong?

OBJECTIVE

To investigate the safety and efficacy of stroke thrombolysis in a local hospital.

DESIGN

Historical cohort study.

SETTING

A tertiary hospital in Hong Kong.

PATIENTS

The outcome of acute ischaemic stroke patients treated with intravenous tissue plasminogen activator between October 2008 and May 2011 was compared to those admitted during the same period who were thrombolysis-eligible, but treated conservatively due to unavailability of the thrombolysis service after-hours.

INTERVENTIONS

Intravenous tissue plasminogen activator.

MAIN OUTCOME MEASURES

Primary outcome was functional independence (modified Rankin Scale score of 2 or below) at 3 months. Safety outcomes were symptomatic intracranial haemorrhage and 3-month mortality. Secondary outcomes were hospital length of stay, direct home discharge, and nursing home discharge.

RESULTS

A total of 48 thrombolysis and 63 non-thrombolysis patients were identified. Fifty-two percent of the thrombolysis group achieved functional independence compared to 24% of non-thrombolysis group (P=0.003), without significant increase in mortality (15% vs 13%, P=0.51) or symptomatic intracranial haemorrhage (4% vs 2%, P=0.58). Twenty-nine percent of the thrombolysis group patients were discharged home directly, versus 6% of non-thrombolysis group (P<0.001). Mean length of stay was shorter for the thrombolysis group (25 vs 35 days; P=0.034). A similar percentage from each group was discharged to nursing homes.

CONCLUSION

Implementation of the stroke thrombolysis service in Hong Kong appeared safe and efficacious. Patients who received thrombolysis had better outcomes compared to non-thrombolysis cohort. Further studies are needed to investigate the economics of stroke thrombolysis in Hong Kong, which may help to improve funding for provision of this service.

An expedited stroke triage pathway: the key to shortening the door-to-needle time in delivery of thrombolysis

OBJECTIVES

To assess time management of stroke thrombolysis triage and functional outcomes in patients receiving recombinant tissue plasminogen activator for hyperacute stroke, and identify bottlenecks in delivery of the treatment.

DESIGN

Prospective study.

SETTING

A university teaching hospital in Hong Kong.

PATIENTS

Patients with suspected hyperacute stroke referred to the stroke thrombolysis team during October 2008 to September 2009.

MAIN OUTCOME MEASURES

Time performance records including door-to-stroke team, door-to-needle, and onset-to-thrombolysis times. Functional outcomes by modified Rankin Scale score at 3 months, and thrombolysis-related complications including haemorrhagic transformations and mortality.

RESULTS

During the 12-month period, 95 thrombolysis calls were received; recombinant tissue plasminogen activator was given intravenously to 17 (18%) of the patients and intra-arterially to 11 (12%). The mean (standard deviation) door-to-stroke team and the door-to-needle times for intravenous recombinant tissue plasminogen activator patients were 33 (25) and 80 (25) minutes, respectively; both were about 20 minutes longer than that recommended by the National Institute of Neurological Disorders and Stroke. The mean National Institute of Health Stroke Scale score for patients received intravenous recombinant tissue plasminogen activator was 16 (standard deviation, 7). The mean (standard deviation) onset-to-treatment time was 144 (42) minutes. Nine (53%) patients who received intravenous recombinant tissue plasminogen activator achieved favourable outcomes at 3 months, with a modified Rankin Scale score of 0 to 1. Symptomatic haemorrhage and mortality occurred in one (6%) patient.

CONCLUSION

A dedicated stroke triage pathway is essential to ensure efficient and safe delivery of thrombolysis therapy. Improvements in door-to-stroke team time through integration with emergency medicine staff and neuroradiologists may improve thrombolysis eligibility.

Patient-specific decision-making for warfarin therapy in nonvalvular atrial fibrillation: how will screening with genetics and imaging help?

BACKGROUND AND PURPOSE

Intracerebral hemorrhage (ICH) accounts for a majority of long-term morbidity and mortality associated with bleeding while on warfarin. Both ICH and warfarin-related ICH appear to have a genetic component. Furthermore, advanced neuroimaging using MRI can now identify individuals at increased risk of ICH. We explore whether screening strategies that include genetic profiling and neuroimaging might improve the safety of chronic anticoagulation for atrial fibrillation by identifying individuals from whom warfarin should be withheld.

METHODS

We used a Markov state transition decision model. Effectiveness was measured in quality-adjusted life-years. Data sources included the English language literature using MEDLINE searches and bibliographies from selected articles along with empirical data from our institutions. The base case was a 69-year-old man with newly diagnosed nonvalvular atrial fibrillation.

RESULTS

For patients at average risk for thromboembolic events and known to possess a hypothetical genetic profile increasing risk for warfarin ICH, anticoagulation remains the preferred strategy until the relative hazard of ICH exceeds 23.8. Genetic profiling would be favored for patients at low risk of thromboembolism (1.5% per year) if the hypothetical gene variant(s) conferred a relative risk of ICH >4.1. Screening strategies in which patients underwent genotyping and MRI before anticoagulation did not improve aggregate patient outcomes unless the predictive power of MRI exceeded current best guess estimates and patients were at low to moderate risk of thromboembolism.

CONCLUSIONS

Currently identified genetic markers of bleeding risk do not confer a risk of ICH sufficiently high to warrant routine genetic testing for patients at average risk of thromboembolism. Even if patients undergo screening with MRI as well as genotyping, currently available data on the role of MRI on risk of ICH and warfarin ICH do not support use of these tests for withholding anticoagulation in patients with atrial fibrillation.

Multimodal computed tomography evaluation before thrombolysis in acute ischaemic stroke

Currently, when stroke patients are offered thrombolytic therapy, their ischaemic stroke subtypes are usually unknown. Given the risk of haemorrhage that accompanies thrombolytic therapy, unselective (or undiscriminating) use of recombinant tissue plasminogen activator in patients without large-artery thromboemboli is potentially hazardous. Advances in computed tomography techniques have enabled the stroke pathophysiology to be quickly delineated by multimodal computed tomography without compromise in time for recombinant tissue plasminogen activator administration. Through description of the investigation of a typical stroke patient, we report how this technique is feasible in a regional hospital and may guide judicious use of recombinant tissue plasminogen activator.

Cardiovascular complications of severe acute respiratory syndrome

BACKGROUND AND AIMS

Severe acute respiratory syndrome (SARS) is a virulent viral infection that affects a number of organs and systems. This study examined if SARS may result in cardiovascular complications.

METHODS AND RESULTS

121 patients (37.5 (SD13.2) years, 36% male) diagnosed to have SARS were assessed continuously for blood pressure, pulse, and temperature during their stay in hospital. Hypotension occurred in 61 (50.4%) patients in hospital, and was found in 28.1%, 21.5%, and 14.8% of patients during the first, second, and third week, respectively. Only one patient who had transient echocardiographic evidence of impaired left ventricular systolic function required temporary inotropic support. Tachycardia was present in 87 (71.9%) patients, and was found in 62.8%, 45.4%, and 35.5% of patients from the first to third week. It occurred independent of hypotension, and could not be explained by the presence of fever. Tachycardia was also present in 38.8% of patients at follow up. Bradycardia only occurred in 18 (14.9%) patients as a transient event. Reversible cardiomegaly was reported in 13 (10.7%) patients, but without clinical evidence of heart failure. Transient atrial fibrillation was present in one patient. Corticosteroid therapy was weakly associated with tachycardia during the second (chi(2) = 3.99, p = 0.046) and third week (chi(2) = 6.53, p = 0.01), although it could not explain tachycardia during follow up.

CONCLUSIONS

In patients with SARS, cardiovascular complications including hypotension and tachycardia were common but usually self limiting. Bradycardia and cardiomegaly were less common, while cardiac arrhythmia was rare. However, only tachycardia persisted even when corticosteroid therapy was withdrawn.

Use of convalescent plasma therapy in SARS patients in Hong Kong

In order to evaluate the efficacy of convalescent plasma therapy in the treatment of patients with severe acute respiratory syndrome (SARS), 80 SARS patients were given convalescent plasma at Prince of Wales Hospital, Hong Kong, between 20 March and 26 May 2003. Good outcome was defined as discharge by day 22 following the onset of SARS symptoms. Poor outcome was defined as death or hospitalization beyond 22 days. A higher day-22 discharge rate was observed among patients who were given convalescent plasma before day 14 of illness (58.3% vs 15.6%; P<0.001) and among those who were PCR positive and seronegative for coronavirus at the time of plasma infusion (66.7% vs 20%; P=0.001).

Initial treatment of immune thrombocytopenic purpura with high-dose dexamethasone

BACKGROUND

The role of high-dose dexamethasone in the treatment of immune thrombocytopenic purpura in adults is controversial. We assessed the effectiveness of high-dose dexamethasone as initial treatment in a series of consecutive adults with immune thrombocytopenic purpura.

METHODS

Consecutive patients with newly diagnosed immune thrombocytopenic purpura and a platelet count of less than 20,000 per cubic millimeter or a platelet count of less than 50,000 per cubic millimeter and clinically significant bleeding were enrolled between January 1997 and December 2000. Oral dexamethasone at a dose of 40 mg per day for four consecutive days was the initial treatment. A response was defined as an increase in the platelet count of at least 30,000 per cubic millimeter and a platelet count of more than 50,000 per cubic millimeter by day 10 after the initiation of treatment. A sustained response was defined as a platelet count of more than 50,000 per cubic millimeter six months after the initial treatment.

RESULTS

Of 157 consecutive patients, 125 were eligible. The mean (+/-SD) platelet count before treatment was 12,200+/-11,300 per cubic millimeter. A good initial response to high-dose dexamethasone occurred in 106 of the 125 patients (85 percent): the platelet count increased by at least 20,000 per cubic millimeter by the third day of treatment, and the mean platelet count was 101,400+/-53,200 per cubic millimeter (range, 50,000 to 260,000 per cubic millimeter) one week after the initiation of treatment. Among the 106 patients with a response, 53 (50 percent) had a sustained response; the other 53 (50 percent) had a relapse within six months, most of them (94 percent) within the first three months. A platelet count of less than 90,000 per cubic millimeter on day 10 was associated with a high risk of relapse. The treatment was well tolerated.

CONCLUSIONS

A four-day course of high-dose dexamethasone is effective initial therapy for adults with immune thrombocytopenic purpura.

Subcutaneous injection of metallic mercury

Deliberate self-injection of metallic mercury into subcutaneous tissue is uncommon. A 41-year-old lady with a history of schizophrenia was admitted to our hospital after deliberate injection of metallic mercury into her right wrist and antecubital fossa. Physical examination was unremarkable except for the injection marks over right antecubital fossa and wrist. The presence of subcutaneous mercury deposits in her right elbow and wrist was confirmed by X-rays and ultrasound scan. Three days later, erythema, swelling, induration and tenderness were seen over the injection sites. At the operation on day 9, mercury streaks were seen within the brachialis muscle belly, surrounded by friable necrotic tissues along the tract. A similar picture was noted in her right wrist. The necrotic tissues and mercury streaks were removed. The patient had been unco-operative and she only received incomplete treatment with dimercaprol and 2,3-dimercaptosuccinic acid. Her total blood mercury level (normal < 50 nmol/L) decreased from 101-151 nmol/L in the first two weeks to 42 nmol/L 3 months later. Her 24-hour urinary mercury excretion (normal < 10 nmol) changed from 55.7-209.5 nmol in the first 7 weeks to 125.4 nmol 3 months later. This case illustrates that soft tissue metallic mercury can produce local necrosis and may allow continuous absorption with persistent elevations in blood and urinary mercury levels. Therefore, early surgical removal of subcutaneous mercury deposits is required to prevent local complications and minimize the risk of systemic absorption and toxicity.