Ki Hyun Cho

Risk Factors and Stroke Mechanisms in Atherosclerotic Stroke Intracranial Compared With Extracranial and Anterior Compared With Posterior Circulation Disease

Background and Purpose— The aim of this study was to investigate differences in risk factors and stroke mechanisms between intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS) and between anterior and posterior circulation atherosclerosis. Methods— A multicenter, prospective, Web-based registry was performed on atherosclerotic strokes using diffusionweighted magnetic resonance imaging and magnetic resonance angiography. Stroke mechanisms were categorized as artery-to-artery embolism, in situ thrombo-occlusion, local branch occlusion, or hemodynamic impairment. Results— Onethousand patients were enrolled from 9 university hospitals. Age (odds ratio [OR], 1.033; 95% confidence interval [CI], 1.018–1.049), male gender (OR, 3.399; 95% CI, 2.335–4.949), and hyperlipidemia (OR, 1.502; 95% CI, 1.117–2.018) were factors favoring ECAS (vs ICAS), whereas hypertension (OR, 1.826; 95% CI, 1.274–2.618; P=0.001) and diabetes mellitus (OR, 1.490; 95% CI, 1.105–2.010; P=0.009) were related to posterior (vs anterior) circulation diseases. Metabolic syndrome was a factor related to ICAS (vs ECAS) only in posterior circulation strokes (OR, 2.433; 95% CI, 1.005–5.890; P=0.007). Stroke mechanisms included arterytoartery embolism (59.7%), local branch occlusion (14.9%), in situ thrombo-occlusion (13.7%), hemodynamic impairment (0.9%), and mixed (10.8%). Anterior ICAS was more often associated with artery-to-artery embolism (51.8% vs 34.0%) and less often associated with local branch occlusion (12.3% vs 40.4%) than posterior ICAS (P<0.001). Conclusions— The prevalence of risk factors and stroke mechanisms differ between ICAS and ECAS, and between anterior and posterior circulation atherosclerosis. Posterior ICAS seems to be closely associated with metabolic derangement and local branch occlusion. Prevention and management strategies may have to consider these differences.

Case Characteristics, Hyperacute Treatment, and Outcome Information from the Clinical Research Center for Stroke-Fifth Division Registry in South Korea

Characteristics of stroke cases, acute stroke care, and outcomes after stroke differ according to geographical and cultural background. To provide epidemiological and clinical data on stroke care in South Korea, we analyzed a prospective multicenter clinical stroke registry, the Clinical Research Center for Stroke-Fifth Division (CRCS-5). Patients were 58% male with a mean age of 67.2±12.9 years and median National Institutes of Health Stroke Scale score of 3 [1-8] points. Over the 6 years of operation, temporal trends were documented including increasing utilization of recanalization treatment with shorter onset-to-arrival delay and decremental length of stay. Acute recanalization treatment was performed in 12.7% of cases with endovascular treatment utilized in 36%, but the proportion of endovascular recanalization varied across centers. Door-to-IV alteplase delay had a median of 45 [33-68] min. The rate of symptomatic hemorrhagic transformation (HT) was 7%, and that of any HT was 27% among recanalization-treated cases. Early neurological deterioration occurred in 15% of cases and were associated with longer length of stay and poorer 3-month outcomes. The proportion of mRS scores of 0-1 was 42% on discharge, 50% at 3 months, and 55% at 1 year after the index stroke. Recurrent stroke up to 1 year occurred in 4.5% of patients; the rate was higher among older individuals and those with neurologically severe deficits. The above findings will be compared with other Asian and US registry data in this article.

Prognostication of Recovery in Patients With Acute Ischemic Stroke Through the Use of Brain SPECT With Technetium-99m—Labeled Metronidazole

Background and Purpose— We hypothesized that technetium-99m-ethylene dicysteine-metronidazole (99mTc-EC-MN) localizes to brain tissue that is hypoxic but viable. This study prospectively evaluated the relationship between neurological outcome and uptake of 99mTc-EC-MN in peri-infarcted regions of the brain. Methods— Eight patients with acute ischemic stroke in the territory of the left middle cerebral artery underwent 99mTc-EC-MN and 99mTc-ethyl cysteinate dimer (ECD) brain SPECTs on the same day during the subacute stage (10.3±2.5 days). The infarct volumes from 99mTc-ECD images (IVECD), infarct volumes from diffusion-weighted MRI images (IVDW), and hypoxic volume (HV) from 99mTc-EC-MN images were calculated. The net infarct volume (NIVECD) was defined as IVECD minus HV. The National Institutes of Health Stroke Scale scores were measured on admission and days 1, 3, 7, and 30. Results— IVECD was greater than IVDW. The lesion-to-normal count-density ratios of 99mTc-EC-MN ranged from 1.80 to 5.96. HV was 60.2±65.2 cm3, and the mean percent HV was 24.5±28.1% of IVECD. NIVECD was 162.6±133.4 cm3 and was significantly smaller than IVECD. NIVECD was significantly correlated with National Institutes of Health Stroke Scale score at 1 month and was a significant predictor of neurological deficit at 1 month. Conclusions— 99mTc-EC-MN brain SPECT can detect hypoxic tissue after acute ischemic stroke and, in combination with 99mTc-ECD brain SPECT, is useful in predicting neurological outcome in ischemic stroke patients.

Grading and Interpretation of White Matter Hyperintensities Using Statistical Maps

Background and Purpose— We aimed to generate rigorous graphical and statistical reference data based on volumetric measurements for assessing the relative severity of white matter hyperintensities (WMHs) in patients with stroke. Methods— We prospectively mapped WMHs from 2699 patients with first-ever ischemic stroke (mean age=66.8±13.0 years) enrolled consecutively from 11 nationwide stroke centers, from patient (fluid-attenuated-inversion-recovery) MRIs onto a standard brain template set. Using multivariable analyses, we assessed the impact of major (age/hypertension) and minor risk factors on WMH variability. Results— We have produced a large reference data library showing the location and quantity of WMHs as topographical frequency-volume maps. This easy-to-use graphical reference data set allows the quantitative estimation of the severity of WMH as a percentile rank score. For all patients (median age=69 years), multivariable analysis showed that age, hypertension, atrial fibrillation, and left ventricular hypertrophy were independently associated with increasing WMH (0–9.4%, median=0.6%, of the measured brain volume). For younger (⩽69) hypertensives (n=819), age and left ventricular hypertrophy were positively associated with WMH. For older (≥70) hypertensives (n=944), age and cholesterol had positive relationships with WMH, whereas diabetes mellitus, hyperlipidemia, and atrial fibrillation had negative relationships with WMH. For younger nonhypertensives (n=578), age and diabetes mellitus were positively related to WMH. For older nonhypertensives (n=328), only age was positively associated with WMH. Conclusions— We have generated a novel graphical WMH grading (Kim statistical WMH scoring) system, correlated to risk factors and adjusted for age/hypertension. Further studies are required to confirm whether the combined data set allows grading of WMH burden in individual patients and a tailored patient-specific interpretation in ischemic stroke-related clinical practice.

Comparative Effectiveness of Standard Care With IV Thrombolysis Versus Without IV Thrombolysis for Mild Ischemic Stroke

Background One third of patients presenting with initially mild strokes have unfavorable outcomes, and the efficacy of intravenous thrombolysis (IVT) in this population has not been proven. This study aimed to evaluate the comparative effectiveness of standard care with IVT versus without IVT in mild stroke patients. Methods and Results Using a multicenter stroke registry database, we identified patients with acute ischemic stroke who presented within 4.5 hours of symptom onset and had initial National Institutes of Health Stroke Scale scores ≤5. Multivariable logistic analysis and propensity score matching were used to adjust for baseline imbalances between the patients who did and did not receive IVT. Adjusted odds ratios and 95% CIs of IVT were estimated for 3‐month modified Rankin Scale scores of 0 to 1 and symptomatic. Of 13 117 patients with stroke who were hospitalized between April 2008 and May 2012, 1386 met the eligibility criteria, and 194 (14.0%) were treated with IVT. For a modified Rankin Scale of 0 to 1 at 3 months, the adjusted odds ratios were 1.96 (95% CI, 1.28 to 3.00; P=0.002) by multivariable logistic analysis and 1.68 (1.10 to 2.56; P=0.02) by propensity score matching analysis, respectively. There was a statistically nonsignificant excess of symptomatic hemorrhagic transformation (odds ratios=3.76 [0.95 to 16.42; P=0.06] and 4.81 [0.84 to 49.34; P=0.09]), respectively. Conclusions In this observational registry‐based study, standard care with IVT is more effective than not receiving IVT in mild ischemic stroke patients, and there is a statistically nonsignificant risk of symptomatic hemorrhagic transformation.

Stroke outcomes are worse with larger leukoaraiosis volumes

Leukoaraiosis or white matter hyperintensities are frequently observed on magnetic resonance imaging of stroke patients. We investigated how white matter hyperintensity volumes affect stroke outcomes, generally and by subtype. In total, 5035 acute ischaemic stroke patients were enrolled. Strokes were classified as large artery atherosclerosis, small vessel occlusion, or cardioembolism. White matter hyperintensity volumes were stratified into quintiles. Mean age (± standard deviation) was 66.3 ± 12.8, 59.6% male. Median (interquartile range) modified Rankin Scale score was 2 (1–3) at discharge and 1 (0–3) at 3 months; 16.5% experienced early neurological deterioration, and 3.3% recurrent stroke. The Cochran-Mantel-Haenszel test with adjustment for age, stroke severity, sex, and thrombolysis status showed that the distributions of 3-month modified Rankin Scale scores differed across white matter hyperintensity quintiles (P < 0.001). Multiple ordinal logistic regression analysis showed that higher white matter hyperintensity quintiles were independently associated with worse 3-month modified Rankin Scale scores; adjusted odds ratios (95% confidence interval) for the second to fifth quintiles versus the first quintile were 1.29 (1.10–1.52), 1.40 (1.18–1.66), 1.69 (1.42–2.02) and 2.03 (1.69–2.43), respectively. For large artery atherosclerosis (39.0%), outcomes varied by white matter hyperintensity volume (P = 0.01, Cochran-Mantel-Haenszel test), and the upper three white matter hyperintensity quintiles (versus the first quintile) had worse 3-month modified Rankin Scale scores; adjusted odds ratios were 1.45 (1.10–1.90), 1.86 (1.41–2.47), and 1.89 (1.41–2.54), respectively. Patients with large artery atherosclerosis were vulnerable to early neurological deterioration (19.4%), and the top two white matter hyperintensity quintiles were more vulnerable still: 23.5% and 22.3%. Moreover, higher white matter hyperintensities were associated with poor modified Rankin Scale improvement: adjusted odds ratios for the upper two quintiles versus the first quintile were 0.66 (0.47–0.94) and 0.62 (0.43–0.89), respectively. For small vessel occlusion (17.8%), outcomes tended to vary by white matter hyperintensitiy volume (P = 0.10, Cochran-Mantel-Haenszel test), and the highest quintile was associated with worse 3-month modified Rankin Scale scores: adjusted odds ratio for the fifth quintile versus first quintile, 1.98 (1.23–3.18). In this subtype, worse white matter hyperintensities were associated with worse National Institute of Health Stroke Scale scores at presentation. For cardioembolism (20.6%), outcomes did not vary significantly by white matter hyperintensity volume (P = 0.19, Cochran-Mantel-Haenszel test); however, the adjusted odds ratio for the highest versus lowest quintiles was 1.62 (1.09–2.40). Regardless of stroke subtype, white matter hyperintensities were not associated with stroke recurrence within 3 months of follow-up. In conclusion, white matter hyperintensity volume independently correlates with stroke outcomes in acute ischaemic stroke. There are some suggestions that stroke outcomes may be affected by leukoaraiosis differentially depending on stroke subtypes, to be confirmed in future investigations.

Different Antiplatelet Strategies in Patients With New Ischemic Stroke While Taking Aspirin

Background and Purpose— Selecting among different antiplatelet strategies when patients experience a new ischemic stroke while taking aspirin is a common clinical challenge, currently addressed by a paucity of data. Methods— This study is an analysis of a prospective multicenter stroke registry database from 14 hospitals in South Korea. Patients with acute noncardioembolic stroke, who were taking aspirin for prevention of ischemic events at the time of onset of stroke, were enrolled. Study subjects were divided into 3 groups according to the subsequent antiplatelet therapy strategy pursued; maintaining aspirin monotherapy (MA group), switching aspirin to nonaspirin antiplatelet agents (SA group), and adding another antiplatelet agent to aspirin (AA group). The primary study end point was the composite of stroke (ischemic and hemorrhagic), myocardial infarction, and vascular death up to 1 year after stroke onset. Results— A total of 1172 patients were analyzed for this study. Antiplatelet strategies pursued in study patients were MA group in 212 (18.1%), SA group in 246 (21.0%), and AA group in 714 (60.9%). The Cox proportional hazards regression analysis showed that, compared with the MA group, there was a reduction in the composite vascular event primary end point in the SA group (hazard ratio, 0.50; 95% confidence interval, 0.27–0.92; P=0.03) and in the AA group (hazard ratio, 0.40; 95% confidence interval, 0.24–0.66; P<0.001). Conclusions— This study showed that, compared with maintaining aspirin, switching to or adding alternative antiplatelet agents may be better in preventing subsequent vascular events in patients who experienced a new ischemic stroke while taking aspirin.

Mononeuropathy Multiplex in a Patient with Chronic Active Hepatitis B

Background Mononeuropathy multiplex is a rare complication during the course of chronic hepatitis B, despite various neuropathies following acute hepatitis B having been reported previously. Case Report A 30-year-old man presented with sensorimotor symptoms in multiple peripheral nerves. The serological tests for hepatitis were consistent with chronic active hepatitis B. After treatment with oral prednisone combined with an antiviral agent, the sensory and motor symptoms improved and hepatitis B virus replication was reduced. Conclusions We suggest that chronic immune-mediated neuropathy associated with hepatitis B virus infection should be considered in the differential diagnosis of patients with hepatitis B.

Recurrent Transient Monocular Blindness with Ophthalmic Artery Stenosis

his medical record did not show any atherosclerotic vascular disease. Physical examination at admission did not reveal any bruits over either of the carotid arteries. No neurological deficits were detected. His blood pressure was 125/82 mm Hg, and his pulse rate was 72 beats/min and regular. Coagulation parameters, including antithrombin III, proDear Sir, Transient monocular blindness (TMB) or amaurosis fugax (AF) is defined as a monocular, transient visual loss lasting a few minutes, which is caused by an abrupt temporary reduction in blood flow to one eye. From increased blood viscosity to vasospasm or multiple occlusions of extracranial arteries, various mechanisms are involved in causing TMB. One of the most clearly demonstrated mechanisms is atherothrombotic embolism from the carotid artery to the ophthalmic artery. However, TMB caused by isolated ipsilateral ophthalmic artery stenosis is very rare. We experienced a patient with recurrent TMB associated with isolated proximal ophthalmic artery stenosis.

Clinical Outcomes of Posterior Versus Anterior Circulation Infarction With Low National Institutes of Health Stroke Scale Scores

Background and Purpose— We compared baseline characteristics and outcomes at 3 months between patients with minor anterior circulation infarction (ACI) versus minor posterior circulation infarction (PCI), including the influence of large vessel disease on outcomes. Methods— This study is an analysis of a prospective multicenter registry database in South Korea. Eligibility criteria were patients with ischemic stroke admitted within 7 days of stroke onset, lesions in either anterior or posterior circulation, and National Institutes of Health Stroke Scale score of ⩽4 at baseline. Patients were divided into 4 groups for further analysis: minor ACI with and without internal carotid artery/middle cerebral artery large vessel disease and minor PCI with and without vertebrobasilar large vessel disease. Results— A total of 7178 patients (65.2±12.6 years) were analyzed in this study, and 2233 patients (31.1%) had disability (modified Rankin Scale score 2–6) at 3 months. Disability was 32.3% in minor PCI and 30.3% in minor ACI (P=0.07), and death was 1.3% and 1.5%, respectively (P=0.82). In a multivariable logistic regression analysis, minor PCI was significantly associated with disability at 3 months when compared with minor ACI (odds ratio, 1.23; 95% confidence interval, 1.09–1.37; P<0.001). In pairwise comparisons, minor PCI with vertebrobasilar large vessel disease was independently associated with disability at 3 months, compared with the other 3 groups. Conclusions— Our study showed that minor PCI exhibited more frequent disability at 3 months than minor ACI. Especially, the presence of vertebrobasilar large vessel disease in minor PCI had a substantially higher risk of disability. Our results suggest that minor PCI with vertebrobasilar large vessel disease could require more meticulous care and are important targets for further study.