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Dive into the research topics where Sun U. Kwon is active.

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Featured researches published by Sun U. Kwon.


Stroke | 2005

Cilostazol Prevents the Progression of the Symptomatic Intracranial Arterial Stenosis The Multicenter Double-Blind Placebo-Controlled Trial of Cilostazol in Symptomatic Intracranial Arterial Stenosis

Sun U. Kwon; Yong-Jin Cho; Jaseong Koo; Hee-Joon Bae; Yong-Seok Lee; Keun-Sik Hong; Jun Hong Lee; Jong S. Kim

Background and Purpose— Cilostazol, a phosphodiesterase inhibitor, has been reported to reduce restenosis rate after coronary angioplasty and stenting. This study was performed to investigate the effect of cilostazol on the progression of intracranial arterial stenosis (IAS). Methods— We randomized 135 patients with acute symptomatic stenosis in the M1 segment of middle cerebral artery or the basilar artery to either cilostazol 200 mg per day or placebo for 6 months. Aspirin 100 mg per day was also given to all patients. Patients with potential embolic sources in the heart or extracranial arteries were excluded. IAS was assessed by magnetic resonance angiogram (MRA) and transcranial Doppler (TCD) at the time of recruitment and 6 months later. The primary outcome was the progression of symptomatic IAS on MRA and secondary outcomes were clinical events and progression on TCD. Results— Thirty-eight patients were prematurely terminated. Dropout rates and reasons for dropouts were similar between the cilostazol and placebo groups. There was no stroke recurrence in either cilostazol or placebo group, but there was 1 death and 2 coronary events in each group. In cilostazol group, 3 (6.7%) of 45 symptomatic IAS progressed and 11 (24.4%) regressed. In placebo group, 15 (28.8%) of symptomatic IAS progressed and 8 (15.4%) regressed. Progression of symptomatic IAS in cilostazol group was significantly lower than that in placebo group (P=0.008) Conclusion— Our study suggests that symptomatic IAS is a dynamic lesion and cilostazol may prevent its progression.


Cerebrovascular Diseases | 2005

Poststroke Fatigue: Characteristics and Related Factors

Smi Choi-Kwon; Sung W. Han; Sun U. Kwon; Jong S. Kim

Background and Purpose: Poststroke fatigue (PoSF) is a common, but poorly studied problem. The purpose of the present study was to elucidate the characteristics of and the factors associated with PoSF. Methods: We studied 220 consecutive outpatients at an average of 15 months after the onset of stroke. The presence of poststroke depression (PSD) and poststroke emotional incontinence were identified with the use of a standardized questionnaire. The presence of PoSF was assessed using the visual analogue scale and Fatigue Severity Scale. The presence of prestroke fatigue (PrSF) was also assessed. The impact of PoSF on patients’ daily activities was also assessed using the Fatigue Impact Scale. Results: One hundred and twenty-five patients (57%) had PoSF, 83 (38%) had PrSF and 53 (24%) had PSD. Thirty-six percent of the patients without PrSF and 50% of the patients without PSD had PoSF. The impact of PoSF on patients’ daily activities was more severe in the physical domain as compared with the psychological or cognitive domains (p < 0.01). Multivariate analyses showed that the presence of PrSF (p < 0.01, OR 33.5), high modified Rankin scale (MRS; p < 0.05, OR 3.3), PSD (p < 0.05, OR 2.7) were independently associated with PoSF. Cessation of cigarette smoking (p < 0.05) and the presence of PrSF (p < 0.01) were independently related to PoSF in patients without PSD while decrease in sexual activities (p < 0.05) and the presence of dysarthria (p < 0.05) were related to PoSF in patients without PrSF. Conclusions: Fatigue is a fairly common sequela of stroke patients, exerting an impact on their daily activities, especially physical ones. PrSF is the most important factor related to PoSF, followed by high MRS and PSD. Nevertheless, the causes of PoSF appear multifactorial. Strategies to improve the PoSF should be individualized according to the causative factors.


Journal of stroke | 2013

Stroke Statistics in Korea: Part I. Epidemiology and Risk Factors: A Report from the Korean Stroke Society and Clinical Research Center for Stroke

Keun-Sik Hong; Oh Young Bang; Dong Wha Kang; Kyung Ho Yu; Hee Joon Bae; Jin Soo Lee; Ji Hoe Heo; Sun U. Kwon; Chang Wan Oh; Byung-Chul Lee; Jong S. Kim; Byung Woo Yoon

The aim of the Part I of Stroke Statistics in Korea is to summarize nationally representative data of the epidemiology and risk factors of stroke in a single document. Every year, approximately 105,000 people experience a new or recurrent stroke and more than 26,000 die of stroke, which indicates that every 5 minutes stroke attacks someone and every 20 minutes stroke kills someone in Korea. Stroke accounts for roughly 1 of every 10 deaths. The estimated stroke prevalence is about 795,000 in people aged ≥30 years. The nationwide total cost for stroke care was 3,737 billion Korean won (US


JAMA Neurology | 2008

Undernutrition as a Predictor of Poor Clinical Outcomes in Acute Ischemic Stroke Patients

Sung-Hee Yoo; Jong S. Kim; Sun U. Kwon; Sung-Cheol Yun; Jae-Young Koh; Dong-Wha Kang

3.3 billion) in 2005. Fortunately, the annual stroke mortality rate decreased substantially by 28.3% during the first decade of the 21th century (53.2/100,000 in 2010). Among OECD countries, Korea had the lowest in-hospital 30-day case-fatality rate for ischemic stroke and ranked third lowest for hemorrhagic stroke in 2009. The proportion of ischemic stroke has steadily increased and accounted for 76% of all strokes in 2009. According to hospital registry studies, the 90-day mortality rate was 3-7% for ischemic stroke and 17% for intracerebral hemorrhage. For risk factors, among Korean adults ≥30 years of age, one in 3-4 has hypertension, one in 10 diabetes, and one in 7 hypercholesterolemia. One in 3 Korean adults ≥19 years of age is obese. Over the last 10 years, the prevalence of hypertension slightly decreased, but the prevalence of diabetes, hypercholesterolemia, and obesity increased. Smoking prevalence in men has decreased, but is still as high as 48%. This report could be a valuable resource for establishing health care policy and guiding future research directions.


Stroke | 2005

Significance of Susceptibility Vessel Sign on T2*-Weighted Gradient Echo Imaging for Identification of Stroke Subtypes

Kyung-Hee Cho; Jong S. Kim; Sun U. Kwon; A-Hyun Cho; Dong-Wha Kang

OBJECTIVE To determine whether changes in nutritional status in the first week after acute ischemic stroke and undernutrition predicts poor clinical outcomes. DESIGN Prospective observational study. SETTING Tertiary university hospital. PATIENTS We included 131 acute ischemic stroke patients who underwent nutritional assessments within 24 hours and at 1 week after symptom onset. MAIN OUTCOME MEASURES Undernutrition was diagnosed when 1 or more of the following 5 parameters were present: (1) weight loss 10% or more during the past 3 months or 6% or more during the week after admission, (2) a weight index less than 80%, (3) a serum albumin level less than 3.0 g/dL, (4) a transferrin level less than 150 mg/dL, or (5) a prealbumin level less than 10 mg/dL. We assessed poststroke complications and 3-month outcome using modified Rankin Scale responder analysis. RESULTS Of 131 patients included in this study, undernutrition was observed in 16 (12.2%) patients at admission and in 26 (19.8%) at 1 week. Multiple logistic regression analysis showed that baseline undernutrition independently predicted 1-week undernutrition (odds ratio [OR], 14.85; 95% confidence interval [CI], 3.52-62.76; P< .001) and poststroke complications (OR, 6.72; 95% CI, 1.09-41.56; P= .04), and that 1-week undernutrition (OR, 4.49; 95% CI, 1.07-18.94; P= .04) and 1-week National Institutes of Health Stroke Scale score (OR, 1.76; 95% CI, 1.31-2.37; P< .001) independently predicted poor 3-month outcomes. CONCLUSIONS These findings suggest that acute ischemic stroke patients with baseline undernutrition are being undernourished during hospitalization. Strategic nutritional support, particularly in patients with baseline undernutrition, may improve clinical outcomes.


Stroke | 2005

Lesion Patterns and Stroke Mechanism in Atherosclerotic Middle Cerebral Artery Disease Early Diffusion-Weighted Imaging Study

Dae K. Lee; Jong S. Kim; Sun U. Kwon; Sung-Hee Yoo; Dong-Wha Kang

Background and Purpose— In contrast to platelet-rich white thrombi, red thrombi in the heart are rich in fibrin and trapped erythrocytes. The magnetic susceptibility effect of deoxygenated hemoglobin in red thrombi may result in hypointense signals on T2*-weighted gradient echo imaging (GRE). We tested the hypothesis that a GRE susceptibility vessel sign (SVS) is specific for cardioembolic stroke. Methods— This retrospective study examined data from acute ischemic stroke patients who underwent diffusion-weighted imaging, GRE and magnetic resonance angiography (MRA) within 24 hours of stroke onset and who had symptomatic occlusion of large intracranial arteries in the circle of Willis. Hypointense signals within vascular cisterns on GRE corresponding to symptomatic vascular occlusion were termed “GRE SVS.” Recanalization was assessed on follow-up MRA performed within 7 days of onset. The relationships between GRE SVS and stroke subtypes and subsequent recanalization were explored. Results— Of the 95 patients who met the inclusion criteria, GRE SVS was observed in 45 (47.4%). GRE SVS was more commonly associated with cardioembolic stroke patients (31 of 40, 77.5%) than with other stroke subtypes (14 of 55, 25.5%; P<0.001). In 66 patients who underwent follow-up MRA, GRE SVS was associated with subsequent recanalization (P<0.001). Multivariate analysis showed that GRE SVS was an independent predictor of cardioembolic stroke and subsequent recanalization (odds ratio, 10.75 and 4.26; 95% CI, 3.68 to 31.47 and 1.12 to 16.30). Conclusions— GRE SVS may predict cardioembolic stroke and subsequent recanalization. Identifying clot composition may be important in choosing the optimal treatment based on clot characteristics.


Cerebrovascular Diseases | 2002

Intracranial Dural Arteriovenous Fistulas: Analysis of 60 Patients

Sun J. Chung; Jong S. Kim; Jong C. Kim; Soon K. Lee; Sun U. Kwon; Myoung C. Lee; Dae Chul Suh

Background and Purpose— Patterns and mechanisms of stroke in patients with atherosclerotic middle cerebral artery (MCA) disease remain unclear. We sought to identify lesion patterns and stroke mechanisms associated with MCA disease using early diffusion-weighted imaging (DWI). Methods— We reviewed 185 acute ischemic stroke patients who had (1) symptomatic lesions located in the unilateral MCA territory on DWI performed within 48 hours of symptom onset, and (2) either corresponding MCA disease, internal carotid artery disease, or cardioembolism. Acute DWI lesion patterns were classified as (1) single (small perforator <2 cm; large perforator ≥2 cm; pial; large territorial; border-zone) and (2) multiple. Results— MCA disease was diagnosed in 63 patients, 32 (50.8%) of whom showed multiple lesions. Concomitant perforator and pial infarcts (14/63, P<0.001), concomitant perforator, pial, and border-zone infarcts (9/63, P<0.001), and single small perforator infarcts (12/63, P=0.001) were identified more often in patients with MCA disease than in those with cardioembolism or internal carotid artery disease. Small perforator infarcts were more common in patients with milder stenosis than with severe stenosis or occlusion of MCA (P<0.001). Whether they occurred singly or in addition to other lesions, pial infarcts were identified more often in patients with severe stenosis or occlusion of MCA (P=0.001). Conclusions— Perforating artery infarcts, whether single or occurring in addition to pial or border-zone infarcts, are lesion patterns specific for MCA disease. This suggests that local branch occlusion and coexisting distal embolization may be a common stroke mechanism in patients with MCA disease.


Stroke | 2012

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

Jong S. Kim; Hyun-Wook Nah; Sea Mi Park; Su-Kyung Kim; Ki Hyun Cho; Jun Lee; Yong-Seok Lee; Jei Kim; Sang-Won Ha; Eung-Gyu Kim; Dong-Eog Kim; Dong-Wha Kang; Sun U. Kwon; Kyung-Ho Yu; Byung-Chul Lee

Objective: To analyze and update the clinical symptomatology, CT and MRI findings, angiographic features, and therapeutic outcomes of patients with dural arteriovenous fistulas (DAVFs). Background: Studies of DAVFs in a large number of patients have seldom appeared in neurology literature. Methods: The authors investigated 60 consecutive patients with DAVFs who were admitted between January 1991 and January 2001. The DAVFs were graded into five types according to the classification of Cognard et al. [Radiology 1995;194:671–680]. Presumable etiologies, clinical features, imaging findings and therapeutic outcomes were evaluated on the basis of the location and type of DAVFs. Results: Sinus thrombosis, previous trauma, craniotomy, cerebral infarction and acupuncture were detected as possible etiologic factors of DAVFs. The cavernous sinus (57%) was the most common location of DAVFs. Although the neurological symptoms were closely related to the location of the DAVFs, in some patients, there were also symptoms that did not reflect the location. Although the women outnumbered the men, the men presented with aggressive neurological manifestations more often (p < 0.05). Ten out of 12 patients (83%) with DAVFs involving locations other than the large sinuses presented with aggressive neurological manifestations. 70% of brain CTs and 81% of brain MRIs showed abnormal findings suggestive of DAVFs. Of 33 patients who underwent only endovascular embolization, 29 patients (88%) were cured or improved. Radiosurgery and surgical excision done in some patients provided fair results. Patients with DAVFs involving large sinuses showed a better therapeutic outcome than those in whom locations other than the large sinuses were involved, while patients without venous ectasia had more a favorable outcome than those with it (each, p < 0.01). Conclusions: DAVFs result from various etiologic factors, show diverse manifestations usually reflecting the location and can be treated successfully in most patients. Factors related to poor clinical outcome include male sex, the presence of venous ectasia and involved locations other than the large sinuses.


Neurology | 2002

Inability to control anger or aggression after stroke.

June-Gone Kim; Sooseok Choi; Sun U. Kwon; Y. S. Seo

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.


Cerebrovascular Diseases | 2008

Safety and efficacy of MRI-based thrombolysis in unclear-onset stroke. A preliminary report

A-Hyun Cho; Sung-Il Sohn; Moon-Ku Han; Deok Hee Lee; Jong S. Kim; Choong Gon Choi; Chul-Ho Sohn; Sun U. Kwon; Dae Chul Suh; Sang Joon Kim; Hee-Joon Bae; Dong-Wha Kang

Abstract—Using the 10-item Spielberger Trait Anger Scale, the authors interviewed 145 patients with stroke regarding inability to control anger or aggression (ICAA). Poststroke depression and emotional incontinence were also assessed. ICAA was present in 47 patients (32%) and was closely related to motor dysfunction, dysarthria, emotional incontinence, and lesions affecting frontal–lenticulocapsular–pontine base areas. ICAA seems to be one of the major behavioral symptoms in patients with stroke.

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Hee-Joon Bae

Seoul National University Bundang Hospital

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A-Hyun Cho

Catholic University of Korea

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