[Show abstract][Hide abstract] ABSTRACT: This study aimed to estimate the population-attributable risks (PARs) of 9 major risk factors for stroke in Korea through a case-control study and to test the feasibility and validity of internet-based control recruitment.
Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 09/2014;
[Show abstract][Hide abstract] ABSTRACT: In order to improve inter-rater reliability and minimize diagnosis of undetermined etiology for stroke subtype classification, using a stroke registry, we developed and implemented a magnetic resonance imaging (MRI)-based algorithm for acute ischemic stroke subtype classification (MAGIC).
[Show abstract][Hide abstract] ABSTRACT: In 2008, the Ministry of Health and Welfare of South Korea initiated the Regional Comprehensive Stroke Center (CSC) program to decrease the incidence and mortality of stroke nationwide. We evaluated the performance of acute ischemic stroke management after the Regional CSC program was introduced.
[Show abstract][Hide abstract] ABSTRACT: In this study, we evaluated the relationship between the rCBV (regional cerebral blood flow volume) ratio on perfusion-weighted imaging (PWI) and the extent of collateral flow on conventional angiography.
Clinical neurology and neurosurgery. 07/2014; 122C:54-58.
[Show abstract][Hide abstract] ABSTRACT: The safety and efficacy of intravenous tissue plasminogen activator (IV-TPA) in the 3- to 4.5-hour window were largely driven from Western populations, but have not been systematically explored in Korean population.
Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 06/2014;
[Show abstract][Hide abstract] ABSTRACT: The T2(*)-weighted gradient echo image susceptibility vessel sign (GRE SVS) is a well-known indicator of intraluminal thrombi in acute cerebral infarction. The purpose of this study was to evaluate the relationships between thrombus size on GRE SVS and recanalization after intravenous administration of tissue plasminogen activator (IV-tPA).
Journal of cerebrovascular and endovascular neurosurgery. 06/2014; 16(2):85-92.
[Show abstract][Hide abstract] ABSTRACT: Referral from other hospitals is one of the primary causes of delayed thrombolysis therapy after acute ischemic stroke (AIS). We aimed to evaluate whether direct access to a hospital offering intravenous thrombolysis therapy was associated with good functional outcome in AIS patients treated with thrombolysis. We enrolled patients who received intravenous thrombolysis within 3 hours of symptom onset at our stroke center. We divided these patients into two groups: those with a direct admission to our stroke center and those with indirect admission by referral from other community hospitals. We investigated onset-to-door time and onset-to-recombinant tissue plasminogen activator (rtPA) time according to admission mode. We then assessed the association between a direct admission and favorable outcome at 90 days. A total of 232 patients (mean age of 66.6 years, median National Institutes of Health Stroke Scale score of 10) were included. A total of 48.7% of AIS patients treated with intravenous thrombolytic therapy were transferred from other hospitals. Patients who were directly admitted to our stroke center had a shorter onset-to-door time (61 versus 120 minutes, p < 0.001) and onset-to-rtPA time (103 versus 155 minutes, p < 0.001) than those referred from other hospitals. Direct admission was associated with a good outcome with an odds ratio of 2.03 (95% confidence interval 1.051–3.917, p = 0.035), after adjusting for baseline variables. Thrombolysis after direct admission to a hospital offering intravenous thrombolysis therapy could shorten onset-to-rtPA time and improve stroke outcome in patients with AIS.
[Show abstract][Hide abstract] ABSTRACT: Background
Anticoagulation effectively prevents cardioembolic stroke in atrial fibrillation (AF) patients, whereas it is less effective than antiplatelet therapy (AT) in noncardioembolic stroke prevention. We hypothesized that the ischemic lesion pattern and vascular patency would differ according to the antithrombotic treatment status in AF patients.
The medical records of 1078 acute ischemic stroke patients with AF were retrospectively reviewed. Patients were classified according to medication at stroke onset: (1) optimal anticoagulation (OAC; international normalized ratio [INR] 1.7-3.0; n = 36); (2) suboptimal anticoagulation (SOAC; INR ≤1.7; n = 134); (3) AT (n = 285); and (4) control (no antithrombotic medication; n = 623). Imaging and clinical variables of each group were compared with that of controls.
Small cortical or single subcortical infarctions were more common in the OAC group than in controls (6% vs. 1% and 22% vs. 8%, respectively; standardized residual, 2.4 and 2.8). Multicirculatory infarctions were less common in the OAC group than in controls (0% vs. 11%; standardized residual, −2.0). Obstruction of the corresponding artery was less common in the OAC group than in controls (26.5% vs. 46.5%, P = .02). Initial neurologic severity was lower in the OAC and AT groups than in controls (P = .01 and .03, respectively). OAC and AT were independently associated with favorable functional outcome at 3-months (P = .015 and <.001, respectively).
Ischemic stroke can occur during OAC in AF patients. Small cortical or single subcortical lesions were more common than typical cardioembolic lesion patterns. OAC and AT were protective against severe neurologic deficit and independently associated with favorable outcome, but SOAC was not.
Journal of Stroke and Cerebrovascular Diseases. 01/2014;
[Show abstract][Hide abstract] ABSTRACT: Symptomatic steno-occlusion (SYSO) in acute ischemic stroke has a significant impact on treatment options and prognosis. However, the prevalence, distribution, clinical characteristics, and outcome of SYSO are not well known.
We retrospectively identified 3,451 patients hospitalized because of ischemic stroke within 24 hours of symptom onset at 9 stroke centers in South Korea. Patients who did not undergo magnetic resonance imaging were excluded. SYSO was defined as stenosis or occlusion of cerebral arteries with relevant ischemic lesions in the corresponding arterial territory. The number, location, and severity of SYSOs and their effects on functional outcome were analyzed.
In total, 1,929 of 3,057 subjects (63.1%) had SYSO. The most frequently affected vessels were the middle cerebral artery (34.6%), extracranial internal carotid artery (14%), vertebral artery (12.4%), and basilar artery (8.7%). SYSO predicted poor outcome on the modified Rankin Scale 3-6 (odds ratio, 1.77; 95% confidence interval, 1.46-2.15) with adjustments. Involvement of 2 or more vessels was observed in 30.6% of patients with SYSO and independently increased the risk of poor outcome (odds ratio, 2.76; 95% confidence interval, 2.12-3.59). The severity of SYSO was associated with outcome and showed a significant dose-response trend (P<0.001). The effect of SYSO on outcome did not significantly differ by individual arterial location (P for contrast=0.21).
Approximately 60% of patients with acute ischemic stroke had SYSO, and the severity and number were inversely correlated with outcome. The results suggest that SYSO could predict stroke outcome.
[Show abstract][Hide abstract] ABSTRACT: Objective
In this study, we evaluated the relationship between the rCBV (regional cerebral blood flow volume) ratio on perfusion-weighted imaging (PWI) and the extent of collateral flow on conventional angiography.
We recruited 98 patients with AIS (within 24 h after ischemic events). All the patients were evaluated by MRI, including PWI and diffusion-weighted imaging (DWI), and underwent digital subtraction angiography (DSA) of the brain. We hypothesized that the rCBV ratio on PWI could reveal the extent of the blood flow and predict early neurological deterioration (END) within 7 days after AIS.
The rCBV ratio on PWI was significantly correlated with its extent on DSA (p < 0.01). During the observation period, 24 patients (24.5%) experienced END. The univariate analysis revealed that severe neurological deficit at admission (p < 0.01), the volume of the ischemic lesion on DWI (p < 0.01), poor blood flow on DSA (p < 0.01), the presence of DPM (p = 0.05) and a low rCBV ratio on PWI (p < 0.01) were related to END occurrence. The multivariate analysis showed that the presence of a low rCBV ratio on PWI was independently significant as a correlate of END (OR, 5.64; 95% CI, 1.68–18.90; p < 0.01).
This study shows that the rCBV ratio on PWI may be a useful tool to reveal the status of blood flow after AIS. Moreover, the extent of collateral flow may be an important parameter that subtly influences the fate of DPM in AIS.
Clinical Neurology and Neurosurgery. 01/2014; 122:54–58.
[Show abstract][Hide abstract] ABSTRACT: Background
This study aimed to estimate the population-attributable risks (PARs) of 9 major risk factors for stroke in Korea through a case–control study and to test the feasibility and validity of internet-based control recruitment.
From April 2008 to September 2009, controls were enrolled via internet after providing consent for participation through a web-based survey. The cases included patients who were admitted to the participating centers due to acute stroke or transient ischemic attack within 7 days of onset during the study period. Each control was age- and sex-matched with 2 cases. Adjusted odd ratios, age-standardized prevalence, and PARs were estimated for the 9 major risk factors using the prevalence of risk factors in the control group and the age and sex characteristics from Korea's national census data.
In total, 1041 controls were matched to 2082 stroke cases. Because of a shortage of elderly controls in the internet-based recruitment, 248 controls were recruited off-line. The PARs were 23.44%, 10.95%, 51.32%, and 6.35% for hypertension, diabetes, smoking, and stroke history, respectively. Hypercholesterolemia, atrial fibrillation, obesity, coronary heart disease, and a family history of stroke were not associated with stroke. Comparison with education and religion of the control group with that mentioned in the national census data showed a notable difference.
The study results imply that internet-based control recruitment for a case–control study requires careful selection of risk factors with high self-awareness and effective strategies to facilitate the recruitment of elderly participants.
Journal of Stroke and Cerebrovascular Diseases. 01/2014;
[Show abstract][Hide abstract] ABSTRACT: Systemic atherosclerosis is involved in ischemic damages and cardioembolism after atrial fibrillation (AF)-related ischemic stroke (IS). Platelet activation is a critical factor in systemic atherosclerosis; however, there is little information regarding the role of platelet activation on the outcome of AF-related IS. We investigated the relationship between adenosine diphosphate (ADP)-induced platelet aggregation and the long-term outcomes of AF-related IS. We studied 249 patients who were exclusively treated with anticoagulation therapy after they had experienced AF-related IS. We evaluated their platelet function 5 days after admission to the hospital by using an optic platelet aggregometer test. We also assessed the prognoses of patients 90 days after the AF-related IS. Our results showed that ADP-induced platelet aggregation was positively correlated with CHA2DS2-VASc scores (r = .285, P < .01). Totally, 107 (43.0%) patients had a poor outcome at 90 days after IS. Univariate analysis showed that the following factors significantly contribute to a poor outcome: older age (odds ratio [OR] = 1.07, confidence interval [CI] 1.04-1.10, P < .01), a history of stroke (OR = 3.24, CI 1.61-6.53, P < .01), high scores on the National Institutes of Health Stroke Scale (NIHSS; OR = 1.25, CI 1.18-1.32, P < .01), increased white blood cell counts (OR = 1.12, CI 1.02-1.24, P < .01), high CHA2DS2-VASc scores (≥5, OR = 7.31, CI 3.36-15.93, P = .025), and the highest tertile of ADP-induced platelet aggregation (≥72%, OR = 3.17, CI 1.67-5.99, P < .01). Of these factors, high NIHSS scores (OR = 1.27, CI 1.20-1.36, P < .01), high CHA2DS2-VASc scores (OR = 4.69, CI 1.21-18.14, P = .03), and the highest tertile of ADP-induced platelet aggregation (OR = 2.49, CI 1.17-5.27, P = .02) were independently associated with a poor outcome at 90 days after IS. Therefore, our results suggest that platelet activation might affect the outcome of AF-related IS.
Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 11/2013;
[Show abstract][Hide abstract] ABSTRACT: Although ethnic or cultural differences affect prevalence of cardiovascular risk factors, limited information is available about the age- and gender-stratified prevalence of the risk factors in Asian stroke population.
We assessed gender- and age-stratified prevalences of major risk factors in Korean stroke patients, and assumed that the gender differences are attenuated by adjustment with lifestyle factors.
Using the nationwide hospital-based stroke registry, we identified 9417 ischemic stroke patients admitted between April 2008 and January 2011. Prevalence of hypertension, diabetes, hyperlipidemia, atrial fibrillation, prior stroke, and coronary heart disease was assessed in both genders by age groups. We analyzed gender differences of the prevalence among the age groups by calculating prevalence ratio, and further explored the influence of lifestyle factors on the gender difference in multivariable analyses.
Hypertension and hyperlipidemia were more common in men until middle age, but after that more common in women, whereas diabetes was more common in women after 65 years of age. Atrial fibrillation increased steadily with age in both genders but was more common in women through all age groups. Prior stroke and coronary heart disease showed inconsistent gender differences. Gender differences in hypertension and diabetes among the age groups were attenuated by adjustment with accompanying risk factors including lifestyle factors.
Korean women with stroke had more hypertension and hyperlipidemia after middle age, more diabetes after 65 years, and more atrial fibrillation throughout all ages. Strategies to control risk factors in women at risk for stroke are eagerly needed.
International Journal of Stroke 10/2013; · 2.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The drip and ship paradigm for stroke patients enhances the rate of using intravenous tissue plasminogen activator (IVT) in community hospitals. The safety and outcomes of patients treated with IVT for acute ischemic stroke (AIS) under the drip and ship paradigm were compared with patients directly treated at a comprehensive stroke center in the Busan metropolitan area of Korea. This was a retrospective study of patients with AIS treated with IVT between January 2009 and January 2012. Information on patients' baseline characteristics, neuroimaging, symptomatic intracerebral hemorrhage (sICH), and outcome 90 days after using IVT was obtained from our stroke registry. We surveyed stroke neurologists regarding their pattern of post-thrombolysis care. During the observation periods, we selected 317 patients using IVT. Among these, 239 patients received IVT at our stroke center, and 78 were treated at 21 community hospitals under the drip and ship paradigm. Initial neurologic deficits and the size of ischemic lesions on magnetic resonance imaging were much more severe in patients treated with IVT under the drip and ship paradigm compared with patients treated at our comprehensive stroke center. The prevalence of a poor outcome (modified Rankin Scale score 3-6) 90 days after IVT was much higher in patients treated with the drip and ship paradigm than in those treated at our comprehensive stroke center. Regarding the occurrence of sICH, there was no significant difference between the 2 groups. The clinical characteristics and outcomes after using IVT under the drip and ship paradigm may differ greatly among stroke care systems.
Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 10/2013;
[Show abstract][Hide abstract] ABSTRACT: Neurologic complications during carotid artery stenting (CAS) are usually associated with distal embolic event. These embolic incident during CAS are highly associated with the carotid plaque instability. The current study was undertaken to identify the angiographic characteristics of carotid plaque vulnerability, which was represented as filling defect in the cerebral protection filters during CAS.
A total of 107 patients underwent CAS with use of a distal protection filter. Angiographic carotid plaque surface morphology was classified as smooth, irregular, and ulcerated. To determine predictable factors of filling defect in the protection filters, 11 variables were retrospectively analyzed which might influence filling defect in the protection filters during CAS.
Filling defects during CAS were presented in the 33 cerebral protection filters. In multivariate analysis, angiographic ulceration [odds ratio (OR), 6.60; 95% confidence interval (CI) : 2.24, 19.4; p=0.001], higher stenosis degree (OR, 1.06; 95% CI : 1.00, 1.12; p=0.039), and coexistent thrombus (OR, 7.58; 95% CI : 1.69, 34.05; p=0.08) were highly associated with filling defect in the cerebral protection devices during CAS. Among several variables, angiographic surface ulceration was the only significant factor associated with flow stagnation during CAS (OR, 4.11; 95% CI : 1.33, 12.72; p=0.014).
Plaque surface morphology on carotid angiography can be a highly sensitive marker of plaque instability during CAS. The independent risk factors for filling defect in the filter devices during CAS were plaque ulceration, stenosis degree, and coexistent thrombus.
Journal of Korean Neurosurgical Society 08/2013; 54(2):93-9. · 0.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Despite substantial differences in clinical features between Asian and Western stroke patients, there are no published prognostic tools validated in an Asiatic population for thrombolytic therapy. We assessed the ability of the iScore to predict the clinical response after intravenous thrombolysis with tissue plasminogen activator (tPA) in a Korean stroke population.
We applied the iScore to eligible participants in the nationwide multicenter stroke registry in Korea. Main outcome measures were poor functional outcome defined as having a modified Rankin Scale score 3-6 and death at 3 months. Symptomatic intracranial hemorrhage (sICH) was evaluated as a safety outcome. C statistic was calculated to assess performance of iScore.
Among 4760 patients with an acute ischemic stroke, 622 (13.1%) received tPA, 548 patients had complete information for the analysis. C statistics for poor functional outcome and death at 3 months were .813 (95% confidence interval [CI]: .778-.848) and .820 (95% CI: .769-.872), respectively. Overall, there was a high correlation between observed and expected outcome for poor functional outcome (Pearson correlation coefficient, r = .982) and for death at 3 months (r = .950) at the risk score level. An iScore of 180 or more was associated with a more than 2 times risk of poor functional outcome and about 6 times risk of death at 3 months. There was an interaction between the iScore and tPA for a poor functional outcome (P value for the interaction < .001). We found a gradient effect in the incident risk of sICH with the iScore.
The iScore reliably predicts stroke outcomes after tPA in Asiatic population.
Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 06/2013;
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND AND PURPOSE: Several stroke risk scores for prediction of functional outcome have been developed, but rarely validated in Asian populations. We assessed the validity of the iScore, recently developed from Canadian stroke population, in an Asian stroke population from Korea. METHODS: We applied the iScore to 4061 eligible participants with acute ischemic stroke in the nationwide multicenter stroke registry in Korea. The main outcome was poor functional outcome defined as having a modified Rankin Scale 3 to 6 at 3 months after stroke onset. The secondary outcome was death at 3 months. C-statistics were calculated to assess performance of the iScore. RESULTS: Poor functional outcome was found in 1496 patients (36.8%), whereas death at 3 months occurred in 294 patients (7.2%). C-statistics were 0.819 (95% confidence interval, 0.805-0.833) for poor functional outcome and 0.861 (95% confidence interval, 0.840-0.883) for death. Overall, there was a high correlation between observed and expected outcomes for poor functional outcome (Pearson correlation coefficient, r=0.990) and for death (r=0.969) according to risk score. CONCLUSIONS: The iScore reliably predicts poor functional outcome or death at 3 months after stroke in Korean patients.
[Show abstract][Hide abstract] ABSTRACT: Organized inpatient stroke care is one of the most effective therapies for improving patient outcomes. Many stroke centers have been established to meet this need, however, there are limited data on the effectiveness of these organized comprehensive stroke center (CSC) in the real-world setting. Our aim is to determine whether inpatient care following the establishment of CSC lowers mortality of patients with acute ischemic stroke (AIS).
Based on a prospective stroke registry, we identified AIS patients hospitalized before and after the establishment of a CSC. We observed all-cause mortality within 30 days from time of admission. Logistic regression was used to determine whether the establishment of the CSC affects independently the 30-day all-cause mortality.
A total of 3,117 consecutive patients with AIS were admitted within seven days after the onset of the symptoms. Unadjusted 30-day mortality was lower for patients admitted to our hospital after the establishment of the CSC than before (5.9% vs. 8.2%, P=0.012). Advanced age, female gender, previous coronary artery disease, non-smoking, stroke subtype, admission on a holiday, referral from other hospitals, high NIHSS on admission, and admission before the establishment of CSC were associated with increased 30-day stroke case fatality. After adjustment for these factors, stroke inpatient care subsequent to the establishment of the CSC was independently associated with lower 30-day mortality (OR, 0.57; 95% CI, 0.412-0.795).
Patients treated after the establishment of a CSC had lower 30-mortality rates than ever before, even adjusting for the differences in the baseline characteristics. The present study reveals that organized stroke care in a CSC might improve the outcome after AIS.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND AND PURPOSE: Since the Vascular Cognitive Impairment Harmonization Standards (VCIHS) neuropsychological test protocol was proposed by the National Institute of Neurological Disorders and Stroke and Canadian Stroke Network, no studies have applied this neuropsychological protocol to poststroke survivors in a large-scale, multicenter stroke cohort. We determined the frequency of vascular cognitive impairment (VCI) and investigated the feasibility of using the Korean version of the VCIHS neuropsychological protocol in a multicenter, hospital-based stroke cohort in Korea. METHODS: We prospectively enrolled 620 subjects with ischemic stroke within 7 days of symptom onset among 899 patients who were consecutively admitted to 12 university hospitals in Korea. Neuropsychological assessments using the 60-minute Korean VCIHS neuropsychological protocol were administered at 3 months after stroke. RESULTS: Of the 620 patients, 506 were followed up at 3 months after stroke. Of these, 353 (69.8%) were evaluated for cognitive function using the 60-minute Korean VCIHS neuropsychological protocol. The frequency of VCI at 3 months was 62.6%: VCI with no dementia in 49.9% and vascular dementia in 12.7%. Old age (P=0.014), poor functional outcomes at 3 months (P=0.029), and stroke subtypes other than small vessel disease (P=0.004) were independent risk factors of VCI. CONCLUSIONS: VCI, evaluated using the Korean VCIHS neuropsychological protocol, is substantial at 3 months after ischemic stroke in Korea. The use of the 60-minute Korean VCIHS neuropsychological protocol was feasible in large-scale multicenter studies.
[Show abstract][Hide abstract] ABSTRACT: Malignant middle cerebral artery (MCA) infarction occurs in 10% of all ischemic strokes and these severe strokes are associated with high mortality rates. Recent clinical trials demonstrated that early decompressive craniectomy reduce mortality rates and improves functional outcomes in healthy young patients (less than 61 years of age) with a malignant infarction. The purpose of this study was to assess the efficacy of decompressive craniectomy in elderly patients (older than 70 years of age) with a malignant MCA infarction.
Between February 2008 and October 2011, 131 patients were diagnosed with malignant MCA infarctions. We divided these patients into two groups: patients who underwent decompressive craniectomy (n = 58) and those who underwent conservative care (n = 73). A cut-off point of 70 years of age was set, and the study population was segregated into those who fell above or below this point. Mortality rates and functional outcome scores were assessed, and a modified Rankin Scale (mRS) score of > 3 was considered to represent a poor outcome.
Mortality rates were significantly lower at 29.3% (one-month mortality rate) and 48.3% (six-month mortality rate) in the craniectomy group as compared to 58.9% and 71.2%, respectively, in the conservative care group (p < 0.001, p = 0.007). Age (≥70 years vs. < 70 years) did not statistically differ between groups for the six-month mortality rate (p = 0.137). However, the pre-operative National Institutes of Health Stroke Scale (NIHSS) score did contribute to the six-month mortality rate (p = 0.047).
Decompressive craniectomy is effective for patients with a malignant MCA infarction regardless of their age. Therefore, factors other than age should be considered and the treatment should be individualized in elderly patients with malignant infarctions.
Journal of cerebrovascular and endovascular neurosurgery. 06/2012; 14(2):65-74.