Kyung-Yul Lee

Yonsei University Hospital, Sŏul, Seoul, South Korea

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Publications (37)64.06 Total impact

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    ABSTRACT: We report a case of delayed cerebral infarction due to stent longitudinal folding deformation following carotid artery stenting using a self-expandable stent with an open-cell design. The stented segment of the left common carotid artery was divided into two different lumens by this folding deformation, and the separated lumens became restricted with in-stent thrombosis. Although no established method of managing this rare complication exists, a conservative approach was taken with administration of anticoagulant and dual antiplatelet therapy. No neurological symptoms were observed during several months of clinical follow-up after discharge.
    Korean journal of radiology: official journal of the Korean Radiological Society 11/2014; 15(6):858-61. · 1.32 Impact Factor
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    ABSTRACT: Background: The Effect of Cilostazol in Acute Lacunar Infarction Based on Pulsatility Index of the Transcranial Doppler (ECLIPse) study showed a significant decrease in the transcranial Doppler (TCD) pulsatility index (PI) with cilostazol treatment at 90 days after acute lacunar infarction. The aim of the present study was to perform a subgroup analysis of the ECLIPse study in order to explore the effect of cilostazol in acute lacunar infarction based on cerebral white matter hyperintensities (WMH) volume. Methods: The ECLIPse study was a multicenter, randomized, double-blind, placebo-controlled trial that evaluated the difference between the efficacy of cilostazol and a placebo to reduce the PI in patients with acute lacunar infarction using serial TCD examinations. The primary outcome was changes in the PIs of the middle cerebral artery (MCA) and basilar artery at 14 and 90 days from the baseline TCD study. For this subgroup analysis, using semi-automated computerized software, the WMH volume was measured for those subjects for whom fluid-attenuated inversion recovery (FLAIR) images were available. Results: Of the 203 patients in eight hospitals in the ECLIPse study, 130 participants from six hospitals were included in this subgroup analysis. Cilostazol was given to 63 patients (48.5%) and placebo to 67 patients (51.5%). All baseline characteristics were well balanced across the two groups, and there were no significant differences in these characteristics except in the changes of PI from the baseline to the 90-day point. There was a significant decrease of TCD PIs at 90-day study from baseline in the cilostazol group (p = 0.02). The mean WMH volume was 11.57 cm(3) (0.13-68.45, median 4.86) and the mean MCA PI was 0.95 (0.62-1.50). The changes in PIs from the baseline to 14 days and to 90 days were 0.09 (-0.21 to 0.33) and 0.10 (-0.22 to 0.36). While there were no significant correlations between WMH volume and the changes in PIs, a trend of inverse correlation was observed between the WMH volume and the changes in PIs from the baseline to the 90-day point. For the subgroup analysis, the WMH volume was dichotomized based on its median value (4.90 cm(3)). Cilostazol decreased the TCD PIs significantly at the 90-day point in patients with WMH volumes ≤4.9 cm(3) (p = 0.002). Significant treatment effects were observed in the cilostazol group. Conclusions: This study showed that cilostazol decreased cerebral arterial pulsatility in patients with WMH. Our findings indicate the unique effect of cilostazol in small vessel disease (SVD), especially in patients with mild WMH changes. Further clinical trials focusing on WMH volume and clinical outcomes are required to assess the unique efficacy of cilostazol in SVD. © 2014 S. Karger AG, Basel.
    Cerebrovascular diseases (Basel, Switzerland). 10/2014; 38(3):197-203.
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    ABSTRACT: Clopidogrel is metabolized by the hepatic cytochrome P450 (CYP) system into its active thiol metabolite. CYP3A4 is involved in the metabolism of both clopidogrel and dihydropyridine calcium channel blockers (CCBs). A few reports have suggested an inhibitory interaction between CCBs and clopidogrel. Accordingly, the aim of this study was to determine the effect of CCBs on the antiplatelet activity of clopidogrel by serial P2Y12 reaction unit (PRU) measurements. We assessed changes in antiplatelet activity in patients receiving both clopidogrel and CCBs for at least 2 months prior to enrollment in the study. The antiplatelet activity of clopidogrel was measured by VerifyNow P2Y12 assay in the same patient while medicated with CCBs and at 8 weeks after discontinuation of CCBs. After discontinuation of the CCBs, angiotensin receptor blockers were newly administered to the patients or dosed up for control of blood pressure. Thirty patients finished this study. PRU significantly decreased after discontinuation of CCBs (238.1±74.1 vs. 215.0±69.3; p=0.001). Of the 11 patients with high post-treatment platelet reactivity to clopidogrel (PRU≥275), PRU decreased in nine patients, decreasing below the cut-off value in seven of these nine patients after 8 weeks. Decrease in PRU was not related to CYP2C19 genotype. CCBs inhibit the antiplatelet activity of clopidogrel.
    Yonsei medical journal 05/2014; 55(3):683-8. · 0.77 Impact Factor
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    ABSTRACT: Background: The purpose of this study is to compare the patterns of voiding dysfunction according to the locations of brainstem lesions. Methods: Between November 2008 and December 2011, a total of 30 patients participated in this study. All 30 subjects, consisting of 16 men and 14 women, aged between 41 and 82 years (mean age, 63.0 ± 11.0 years) underwent a urodynamic study within 7 days after the onset of a stroke. Results: Twenty-one (70%) patients had a pontine lesion and 9 (30%) had a medullary lesion. Fourteen of these patients (46.7%) had bladder storage disorder, 7 patients (23.3%) had bladder emptying disorder, and 9 patients (30%) had a normal report. Five of the patients who had a medullary lesion (55.6%) had bladder emptying disorder, whereas only 2 patients who had a pontine lesion (9.5%) had bladder emptying disorder. Thirteen patients who had a pontine lesion (61.9%) showed bladder storage disorder. Discussion: The descending pathway from the midbrain tegmentum is inhibitory, and the pathway from the pontine tegmentum is stimulatory. Because of their location pontine lesions could disrupt the descending fibers of the midbrain tegmentum and medullary lesions could disrupt the descending fibers of the pontine tegmentum.
    European Neurology 09/2013; 70(5-6):291-296. · 1.50 Impact Factor
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    ABSTRACT: The purpose of this study is to present our preliminary experience of the temporary endovascular bypass (TEB) technique using an Enterprise stent for recanalization of acute intracranial artery (IA) occlusion. Patients treated by TEB were enrolled in this retrospective study from January 2009 to May 2010. All the procedures consist of temporary partial deployment and subsequent retrieval of Enterprise stent, supplemented by intra-arterial infusion of urokinase (UK) and/or tirofiban. According to the thrombolysis in cerebral infarction (TICI) classification, recanalization was evaluated with initial and postprocedural angiography. Safety was evaluated related to the procedure and clinical outcomes were assessed by National Institute of Health Stroke Scale (NIHSS) score at discharge and modified Rankin scale (mRS) score at 3 months. Eleven patients (median NIHSS 12.8, mean age 61.6 years, male: female = 8:3) with acute IA occlusion were treated with TEB. All the patients presented with TICI 0, and the occluded vessel was the middle cerebral artery (n=7), the basilar artery (n=1), and the distal ICA occlusion (n = 3). IV infusion of tissue plasminogen activator (tPA) was done in 4 patients and mechanical thrombolysis with intra-arterial UK was performed in 9. Recanalization was achieved in 73% (8 patients; TICI ≥ 2). There were no procedure-related complications except for two asymptomatic intracranial hemorrhages. Improvement (≥ 4 points on the NIHSS) and good outcome (mRS ≤2) after 90 days was shown in six patients (55%). One patient died 6 days after procedure. TEB may be a valuable treatment option in acute thromboembolic IA occlusion without stent implantation.
    Neurointervention. 09/2013; 8(2):80-6.
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    ABSTRACT: Purpose: Cerebral ischemic lesions are frequently observed after carotid artery stenting (CAS), and anti-platelet agents are used to prevent stent thrombosis and peri-procedural complications. However, despite the premedication, cerebral ischemic lesions are observed, suggesting that they may rather be related to anti-platelet resistance. We, therefore, investigated the effects of anti-platelet resistance on the development of cerebral ischemic lesions after CAS. Materials and Methods: We retrospectively reviewed patients who received CAS and selected patients for whom brain MRI was performed within 24 hours after CAS and for whom anti-platelet resistance was checked. Anti-platelet resistance was examined by the VerifyNow system. We analyzed the correlation between anti-platelet resistance and cerebral ischemic lesions detected on follow-up MRI. Results: Among 76 patients, 45 (59.2%) developed new ischemic lesions after CAS. Twelve (15.8%) patients showed aspirin resistance and 50 (65.8%) patients showed clopidogrel resistance. Patients with a new ischemic lesion demonstrated a significantly greater frequency of clopidogrel resistance than those who had no new ischemic lesion (82.2% versus 41.9%, p=0.001). The frequency of aspirin resistance was not significantly different between the groups of patients with and without new ischemic lesions (20.0% versus 9.7%, p=0.340). In multivariate analysis, clopidogrel resistance was a significant risk factor for post-procedural cerebral ischemia. Conclusion: Anti-platelet resistance can be used to predict new ischemic lesions after CAS. Anti-platelet resistance should be evaluated in all patients prior to CAS to prevent ischemic complications related to CAS.
    Yonsei medical journal 03/2013; 54(2):288-94. · 0.77 Impact Factor
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    ABSTRACT: A healthy, 66-year-old, right-handed man was admitted to our university hospital and diagnosed with herpes zoster ophthalmicus (HZO). After 4weeks, he complained of hemichorea on his left side. Brain MRI showed a focal hemorrhage in the right subthalamic area. No evidence of aneurysmal lesion or cerebral angiitis was observed on cerebral angiography.
    Journal of Clinical Neuroscience 02/2013; · 1.25 Impact Factor
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    ABSTRACT: Fluid-attenuated inversion recovery hyperintense vessels (FHVs) are known to reflect stagnant or slow blood flow within the cerebral artery. FHVs are frequently observed in patients with acute cerebral infarction accompanied by arterial occlusion or significant stenosis of the anterior cerebral circulation. However, FHVs have not been studied in the context of posterior cerebral circulation. Thus, we investigated the prevalence of FHVs and its clinical significance in patients with acute posterior cerebral artery (PCA) territory infarction. In this retrospective study, consecutive patients with PCA territory infarction who underwent MRI within 1 week after symptom onset were enrolled. Two neurologists who were blinded to the angiographic findings read the images and determined the presence of FHVs. Afterwards, FHVs were graded according to the extent (subtle or prominent) and location (proximal or distal) of the hyperintense vessels. Neurologic deficits of the patients were assessed by the National Institutes of Health Stroke Scale (NIHSS) upon admission and after 5 days. The clinical outcome between patient groups based on FHVs grading was compared using the NIHSS. Among the patients with PCA occlusion, infarction volume on the diffusion-weighted image was compared between the two groups with and without distal FHVs. FHVs were observed in 25 of the 87 patients (28.7%) with PCA territory infarction and in 65.7% of the 35 patients with significant arterial stenosis (10 patients) or occlusion (25 patients) in the posterior cerebral circulation. Among the 18 patients with PCA occlusion, the NIHSS score was significantly improved in patients with distal FHVs compared to the others (2.00 ± 2.18 vs. 0.56 ± 1.01, p = 0.04). The infarction volume was smaller in the distal FHV group than in the others (8.3 ± 8.7 vs. 16.8 ± 17.6 ml), but the difference was not statistically significant. FHVs are detected in patients with PCA territory infarction, especially in those with an occlusive lesion in the PCA. FHVs can be used as an imaging marker of PCA occlusion. Although this study showed a better clinical improvement in patients with distal FHVs, further study is needed to elucidate the clinical meaning of FHVs in PCA infarction.
    Cerebrovascular diseases extra. 01/2013; 3(1):46-54.
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    ABSTRACT: Background: This study is intended to evaluate the propensities of cilostazol to reduce the pulsatility index (PI) in patients with acute lacunar infarction using the serial transcranial Doppler (TCD) examinations. Methods: In a multicenter, randomized, double-blind, placebo-controlled trial, patients were randomly assigned to receive either placebo or 100 mg cilostazol twice a day as well as aspirin 100 mg a day. The primary outcomes were the changes of middle cerebral artery (MCA) and basilar artery (BA) PIs at 14 and 90 days from the baseline TCD study. This study is registered with ClinicalTrials.gov (NCT00741286). Results: Trial medication was given to 203 patients, with 100 receiving cilostazol and 103 receiving placebo, and 164 were included in the per-protocol analysis of the primary outcome. Results from the linear mixed model showed that significant effects were obtained for time-by-group interactions (p = 0.008 in right MCA, p = 0.015 in left MCA, p = 0.002 in BA), suggesting that changes of PIs from the baseline to the 90-day study were different across the groups. Conclusions: Cilostazol further decreased TCD PIs at 90 days from baseline compared to placebo in acute lacunar infarction. This result may be related to pleiotropic effects, such as vasodilation, beyond its antiplatelet activity.
    European Neurology 11/2012; 69(1):33-40. · 1.50 Impact Factor
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    ABSTRACT: Purpose: Late diagnosis and treatment lead to high mortality and poor prognosis in tuberculous meningitis (TbM). A rapid and accurate diagnosis is necessary for a good prognosis. Neuron-specific enolase (NSE) has been investigated as a biochemical marker of nervous tissue damage. In the present study, the usefulness of NSE was evaluated, and a cut-off value for the differential diagnosis of TbM was proposed. Materials and Methods: Patient charts were reviewed for levels of serum and cerebrospinal fluid (CSF) NSE, obtained from a diagnostic CSF study of samples in age- and gender-matched TbM (n=15), aseptic meningitis (n=28) and control (n=37) patients. Results: CSF/serum NSE ratio was higher in the TbM group than those of the control and aseptic groups (p=0.001). In binary logistic regression, CSF white blood cell count and CSF/serum NSE ratio were significant factors for diagnosis of TbM. When the cut-off value of the CSF/serum NSE ratio was 1.21, the sensitivity was 86.7% and the specificity was 75.4%. Conclusion: The CSF/serum NSE ratio could be a useful parameter for the early diagnosis of TbM. In addition, the authors of the present study suggest a cut-off value of 1.21 for CSF/serum NSE ratio.
    Yonsei medical journal 11/2012; 53(6):1068-72. · 0.77 Impact Factor
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    ABSTRACT: Acute disseminated encephalomyelitis (ADEM) is a monophasic autoimmune demyelinating disease of the central nervous system, which typically follows acute viral or bacterial infection or vaccination. We report a case of ADEM associated with hepatitis C virus (HCV) infection with positive serum and cerebrospinal fluid (CSF) anti-HCV antibody. After steroid treatment, neurologic symptoms were improved. Virus triggers autoimmunity or direct viral invasion plays a part in the genesis of ADEM. This is the first reported case of ADEM with anti-HCV antibody in the CSF.
    Yonsei medical journal 07/2012; 53(4):856-8. · 0.77 Impact Factor
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    ABSTRACT: We report herein a case of hyperacute onset of spontaneous cervical spinal subdural hematoma treated with methylprednisolone pulse therapy that showed good results. A 57-year-old man was admitted for posterior neck pain and paraparesis which occurred an hour ago. MRI revealed a ventral subdural hematoma distributed from the level of C1 down to T3, compressing the spinal cord. Conservative management with methylprednisolone pulse therapy was administered considering the patient's poor general condition. Although emergent surgical decompression is necessary in most cases of spinal subdural hematoma, conservative management with steroid therapy could be effective.
    Yonsei medical journal 07/2011; 52(4):692-4. · 0.77 Impact Factor
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    ABSTRACT: Antiphospholipid antibodies (aPLs) are associated with vascular occlusive events. Lupus anticoagulant (LA) and anticardiolipin antibody (aCL) are two aPLs commonly used for screening test. However, other aPLs are reported to play a role in the thrombotic events in other disorders, especially autoimmune disease. We investigated the clinical significance of the anti-annexin V antibody (aAV) in patients with acute cerebral ischemia; annexin V promotes anticoagulant activity via inhibition of prothrombin activation. A total of 187 patients with acute cerebral infarction or transient ischemic attack, and 66 control subjects were included in this prospective study. IgG type aAV was determined by enzyme-linked immunosorbent sandwich assay in the patient and control groups. The presence of LA and aCL were determined in the patient group using the usual screening method. IgG aAV was detected in 26 of the 187 patients (13.9%), but only in three of the 66 control subjects (4.5%; P=0.043). Among the 26 aAV positive patients, only five patients were positive for LA or aCL. The presence of IgG aAV was significantly associated with acute cerebral ischemia: one stroke event (OR, 4.39; 95% CI, 1.21-16.01), and two or more stroke events (OR, 3.91; 95% CI, 1.09-14.07). IgG aAV was detected in a significant percentage of the patients with acute cerebral ischemia compared with the control group. The presence of IgG aAV did not usually coincide with LA or aCL. Thus aAV should be considered as a possible associated factor for acute cerebral ischemia.
    Journal of the neurological sciences 03/2011; 305(1-2):53-6. · 2.32 Impact Factor
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    ABSTRACT: Intracranial pseudoaneurysm (IPA) is a rare disease entity associated with blunt trauma or penetration injury and less likely surgical or endovascular procedure. Decision of the therapeutic option is difficult and challenging in the treatment of iatrogenic pseudoaneurysm from the middle cerebral artery (MCA) that is necessary to maintain. We report our experience of reconstructive treatment of iatrogenic IPA, which was developed after stenting and balloon angioplasty, in the left MCA with overlapping Enterprise stents.
    Journal of neuroimaging: official journal of the American Society of Neuroimaging 03/2011; 22(2):194-6. · 3.36 Impact Factor
  • Kee Ook Lee, Kyung-Yul Lee
    Neurological Sciences 02/2011; 32(4):743-6. · 1.41 Impact Factor
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    ABSTRACT: Hemorrhage is a major complication of thrombolytic treatment. Concerns have been raised about the risk of hemorrhage in patients having received warfarin. Therefore, different indications for thrombolytic treatment are in use for stroke patients on warfarin. However, it remains uncertain whether the prior warfarin use actually increases their risk of bleeding in patients treated with thrombolysis. This study included 179 consecutive patients who had high-risk cardioembolic sources and received thrombolytic treatment. Patients were treated with intravenous thrombolytic agents, or underwent intraarterial thrombolysis if their international normalized ratio (INR) was ≤1.7. We compared the frequency of bleeding complications between patients with prior warfarin use and those without. We also investigated whether there were differences in functional outcome and recanalization rates between them. A prior warfarin use was present in 28 patients (15.6%). Although INR levels were higher in the prior warfarin group, the frequency of bleeding complications was not different between patients who received prior warfarin and those who did not. No differences were observed in patients with or without prior warfarin use, for successful recanalization rate (Thrombolysis in Myocardial Infarction grade 2 or 3), mortality, or modified Rankin score (≤2) at 3months. Thrombolytic therapy for patients who previously received warfarin and had an INR≤1.7 did not affect bleeding risk, clinical outcome, or recanalization rate. Our data suggest that patients with a history of prior warfarin use may be safely treated with thrombolytic agents when their INR levels are low.
    Journal of the neurological sciences 11/2010; 298(1-2):101-5. · 2.32 Impact Factor
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    ABSTRACT: Claude's syndrome is a distinctive brainstem syndrome characterized by ipsilateral third cranial nerve palsy with contralateral hemiataxia and is due to an intrinsic or extrinsic lesion in the midbrain. We report a case of Claude's syndrome caused by neurocysticercosis infection. A 68 year-old Asian man was admitted to our hospital because of ataxia, left ptosis, and diplopia. Brain magnetic resonance imaging (MRI) showed a cystic lesion in the midbrain, which was surrounded by ring enhancement and peripheral edema. Neurocysticercosis infection was diagnosed by the cerebral spinal fluid study. The patient was treated with albendazole and steroids. A follow-up brain MRI three months later demonstrated the disappearance of a surrounding brain edema and rim enhancement. The most common cause of Claude's syndrome is cerebrovascular disease and malignancy. However, there is no report caused by neurocysticercosis infection. Therefore, if we encounter Claude's syndrome, we should consider neurocysticercosis infection as one of the etiologic factors.
    Yonsei medical journal 11/2010; 51(6):978-9. · 0.77 Impact Factor
  • Jong Yun Lee, Kyung-Yul Lee, Sang Hyun Suh
    Neurology 08/2010; 75(7):668. · 8.30 Impact Factor
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    ABSTRACT: We describe our experience in which a retrievable Enterprise stent was used as a temporary recanalization and embolectomy device in an acute middle cerebral artery (MCA) occlusion after urgent stenting for ipsilateral carotid artery stenosis.
    Neuroradiology 08/2009; 51(8):541-544. · 2.70 Impact Factor
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    ABSTRACT: Transient global amnesia (TGA) patients were retrospectively reviewed to determine the usefulness of high-field strength MRI in detecting probable ischemic lesions in TGA. We investigated the lesion detection rate in patients with TGA using 1.5T and 3.0T MRI. Acute probable ischemic lesions were defined as regions of high-signal intensity in diffusion weighted image with corresponding low-signal intensity in apparent diffusion coefficient map. 3.0T MRI showed 11 out of 32 patients with probable ischemic lesions in the hippocampus with mean lesion size of 2.8 +/- 0.6 mm, whereas 1.5T MRI detected no lesion in any of 11 patients. There were no significant differences in clinical characteristics between the groups of 1.5 and 3.0T MRI. High-field strength MRI has a higher detection rate of probable ischemic lesions than low-field strength MRI in patients with TGA.
    Yonsei medical journal 05/2009; 50(2):211-4. · 0.77 Impact Factor

Publication Stats

192 Citations
64.06 Total Impact Points

Institutions

  • 2004–2013
    • Yonsei University Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2010
    • Seosan Jungang Hospital
      Seishō-gun, North Gyeongsang, South Korea
  • 2007
    • Inje University Paik Hospital
      Sŏul, Seoul, South Korea
  • 2005
    • Hallym University
      Sŏul, Seoul, South Korea