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Dive into the research topics where Kwang Hyun Chung is active.

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Featured researches published by Kwang Hyun Chung.


Medicine | 2015

The Role of Spleen Stiffness in Determining the Severity and Bleeding Risk of Esophageal Varices in Cirrhotic Patients

Hwi Young Kim; Eun Hyo Jin; Won Kim; Jae Young Lee; Hyun-Sik Woo; Sohee Oh; Ji-Yeon Seo; Hong Sang Oh; Kwang Hyun Chung; Yong Jin Jung; Donghee Kim; Byeong Gwan Kim; Kook Lae Lee

AbstractEsophageal varix and its hemorrhage are serious complications of liver cirrhosis. Recent studies have focused on noninvasive prediction of esophageal varices. We attempted to evaluate the association of liver and spleen stiffness (LS and SS) as measured by acoustic radiation force impulse imaging, with the presence and severity of esophageal varices and variceal hemorrhage in cirrhotic patients.We measured LS and SS, along with endoscopic examination of esophageal varices for a total of 125 cirrhotic patients at a single referral hospital in this prospective observational study. The diagnostic utility of noninvasive methods for identifying varices and their bleeding risk was compared, including LS, SS, spleen length, Child-Pugh score, and various serum fibrosis indices.Esophageal varices were present in 77 patients (61.6%). SS was significantly higher in patients with varices than in those without varices (3.58 ± 0.47 vs 3.02 ± 0.49; P < 0.001). A tendency toward increasing SS levels was observed with increasing severity of varices (no varix, 3.02 ± 0.49; F1, 3.39 ± 0.51; F2, 3.60 ± 0.42; F3, 3.85 ± 0.37; P < 0.001). SS was significantly higher in patients who experienced variceal hemorrhage than in those who did not (3.80 ± 0.36 vs 3.20 ± 0.51; P = 0.002). An optimal cut-off value of SS for high-risk varices (≥F2) or variceal hemorrhage was 3.40 m/s.SS was significantly correlated with the presence, severity, and bleeding risk of esophageal varices. Prompt endoscopic evaluation of variceal status and prophylactic measures based on the SS may be warranted for cirrhotic patients.


Pancreas | 2015

Preoperative Diagnosis of Pancreatic Cystic Lesions: The Accuracy of Endoscopic Ultrasound and Cross-Sectional Imaging.

Dong Kee Jang; Byeong Jun Song; Ji Kon Ryu; Kwang Hyun Chung; Ban Seok Lee; Joo Kyung Park; Sang Hyub Lee; Yong Tae Kim; Jae Young Lee

Objective This study aimed to evaluate the accuracy of endoscopic ultrasound (EUS) and cross-sectional imaging including multidetector computed tomography (MDCT) or magnetic resonance imaging (MRI) as a preoperative diagnostic modality for the pancreatic cystic lesions. Methods Three hundred eighteen patients with surgically proven pancreatic cystic lesions were enrolled as a study cohort from 1998 to 2011. Preoperative radiological, EUS, and final histopathologic diagnosis were correlated to measure several kinds of diagnostic performance. Results A total of 318 patients underwent preoperative MDCT, with additional imaging modalities such MRI and/or EUS in 215 (67.6%) and 108 (34.0%) patients, respectively. &kgr; Values among the different modalities were as follows: MDCT versus pathology = 0.52 (P < 0.0001), MDCT + MRI versus pathology = 0.674 (P < 0.0001), and EUS versus pathology = 0.558 (P < 0.0001). The sensitivity and specificity in terms of ability to predict neoplastic cysts were as follows: MDCT, 83.1%/70.0%; MDCT + MRI, 94.7%/58.7%; and EUS, 88.5%/52.9%. The diagnostic accuracies of MDCT and MDCT + MRI were 61.4% (62/101) and 80.5% (173/215), respectively, and that of EUS was 70.4% (76/108). Conclusions Magnetic resonance imaging as an additional diagnostic modality to MDCT increased the accuracy, sensitivity, and specificity, as well in terms of predicting neoplastic cysts.


Digestive Endoscopy | 2015

Small cell- versus large cell-sized metal stent in endoscopic bilateral stent-in-stent placement for malignant hilar biliary obstruction.

Jae Min Lee; Sang Hyub Lee; Kwang Hyun Chung; Jin Myung Park; Woo Hyun Paik; Sang Myung Woo; Woo Jin Lee; Ji Kon Ryu; Yong-Tae Kim

Although the large cell‐sized biliary stent facilitates contralateral stent deployment through the mesh of the first metallic stent for stent‐in‐stent (SIS) technique, there are concerns about its vulnerability to tumor ingrowth. The aim of the present study was to compare the clinical outcomes of endoscopic bilateral SIS placement according to the cell size of a self‐expandable metallic stent (SEMS).


Journal of Gastroenterology and Hepatology | 2016

Prognostic value of CA 19-9 kinetics during gemcitabine-based chemotherapy in patients with advanced cholangiocarcinoma.

Ban Seok Lee; Sang Hyub Lee; Jun Hyuk Son; Dong Kee Jang; Kwang Hyun Chung; Woo Hyun Paik; Ji Kon Ryu; Yong-Tae Kim

Little is known of the prognostic value of CEA/CA 19‐9 kinetics during chemotherapy in patients with advanced cholangiocarcinoma (CCA).


Journal of Gastroenterology and Hepatology | 2016

Reintervention for occluded metal stent in malignant bile duct obstruction: A prospective randomized trial comparing covered and uncovered metal stent

Ban Seok Lee; Ji Kon Ryu; Dong Kee Jang; Kwang Hyun Chung; Won Jae Yoon; Jaihwan Kim; Sang Myung Woo; Sang Hyub Lee; Woo Jin Lee; Yong-Tae Kim

No prospective data are available on comparing covered and uncovered self‐expandable metal stent (SEMS) for reintervention of occluded uncovered metal stents during endoscopic retrograde cholangiopancreatography in patients with malignant distal biliary obstruction.


Journal of Gastroenterology and Hepatology | 2016

Early decrement of serum carbohydrate antigen 19-9 predicts favorable outcome in advanced pancreatic cancer.

Kwang Hyun Chung; Ji Kon Ryu; Ban Seok Lee; Dong Kee Jang; Sang Hyub Lee; Yong-Tae Kim

The role of carbohydrate antigen 19‐9 (CA 19‐9) for predicting treatment outcome in pancreatic ductal adenocarcinoma (PDAC) remains to be elucidated. This study was aimed to determine the correlation between early decrement in CA 19‐9 concentration and prognosis of advanced PDAC after chemotherapy.


World Journal of Gastroenterology | 2015

Risk factors of organ failure in cholangitis with bacteriobilia.

Jae Min Lee; Sang Hyub Lee; Kwang Hyun Chung; Jin Myung Park; Ban Seok Lee; Woo Hyun Paik; Joo Kyung Park; Ji Kon Ryu; Yong Tae Kim

AIM To identify the risk factors for organ failure (OF) in cholangitis with bacteriobilia. METHODS This study included 182 patients with acute cholangitis who underwent percutaneous transhepatic biliary drainage between January 2005 and April 2013. We conducted a retrospective analysis of comprehensive clinical and laboratory data. RESULTS There were 24 cases (13.2%) of OF and five deaths (2.7%). Bile culture was positive for microbial growth in 130 out of 138 (94.2%) patients. In multivariate analysis of 130 patients with positive bile cultures, significant predictive factors for OF were the presence of extended-spectrum beta-lactamase (ESBL) organisms in blood cultures, pre-existing renal dysfunction, and choledocholithiasis as an etiology, with odds ratios of 15.376, 6.319, and 3.573, respectively. We developed a scoring system with a regression coefficient of each significant variable. The OF score was calculated using the following equation: (2.7 × ESBL organisms in blood cultures) + (1.8 × pre-existing renal dysfunction) + (1.3 × choledocholithiasis). This scoring system for predicting OF was highly specific (99.1%) and had a positive predictive value of 86.2%. CONCLUSION ESBL organisms in blood cultures, pre-existing renal dysfunction, and choledocholithiasis are risk factors for OF in cholangitis with bacteriobilia. The OF scoring system may aid clinicians to identify a poor prognosis group.


Gut and Liver | 2015

Hepatitis B Surface Antigen Quantification across Different Phases of Chronic Hepatitis B Virus Infection Using an Immunoradiometric Assay.

Kwang Hyun Chung; Won Seog Kim; Byeong Gwan Kim; Ho-Young Lee; Eunhyo Jin; Yuri Cho; Ji Yeon Seo; Hwi Young Kim; Yong Jin Jung; Ji Won Kim; Ji Bong Jeong; Kook Lae Lee

Background/Aims Quantification of hepatitis B surface antigen (HBsAg) is an emerging serologic test and may be useful for identifying treatment strategies for chronic hepatitis B (CHB). This study aimed to evaluate HBsAg titers during the natural course of CHB and identify correlations between HBsAg titers and hepatitis B virus (HBV) DNA concentrations across different CHB phases measured using an immunoradiometric assay (IRMA). Methods CHB phases were defined on the basis of HBV DNA concentrations, the presence of hepatitis B e antigen/antibody (HBeAg/Ab) and serum alanine aminotransferase levels. Serum HBsAg titers and paired HBV DNA concentrations in the different phases of CHB were compared using 627 serum samples. Results Mean HBsAg titers were significantly higher in the immunotolerant (IT) phase and immunoreactive (IR) HBeAg-positive phase than in the low-replicative (LR) and HBeAg-negative CHB (ENH) states. The correlation between HBsAg titers and HBV DNA concentrations was modest in the IT (n=36, r=0.804, p<0.001) and IR (n=48, r=0.773, p<0.001) phases, and it was poor in the LR state (n=116, r=0.289, p=0.002); however, no significant correlation was observed in the ENH state (n=67, r=0.146, p=0.237) or in the oral nucleos(t)ide analogue-treated group (n=267). Conclusions HBsAg quantification using IRMA might be useful for discriminating different CHB phases and different stages of chronic liver disease.


Endoscopy | 2015

Self-expandable metallic stents vs. plastic stents for endoscopic biliary drainage in hepatocellular carcinoma

Kwang Hyun Chung; Sang Hyub Lee; Jin Myung Park; Jae Min Lee; Dong-Won Ahn; Ji Kon Ryu; Yong-Tae Kim

BACKGROUND AND STUDY AIMS The patency of self-expandable metallic stents (SEMS) is known to be better than plastic stents in the palliation of malignant biliary obstruction. However, data are scarce for obstructive jaundice caused by hepatocellular carcinoma (HCC). This study aimed to compare SEMSs and plastic stents for the palliation of obstructive jaundice in unresectable HCC. PATIENTS AND METHODS A total of 96 patients who underwent endoscopic retrograde biliary drainage with SEMSs or plastic stents were included in this retrospective analysis. The rate of successful biliary drainage, adverse events, stent patency duration, and patient survival were compared between the SEMS (n = 36) and plastic stent (n = 60) groups. RESULTS The rate of successful biliary drainage was similar between the SEMS and plastic stent groups (25/36 [69.4 %] vs. 39/60 [65.0 %]; P = 0.655). Adverse events occurred in 6 patients (16.7 %) in the SEMS group and 13 patients (21.7 %) in the plastic stent group (P = 0.552). The median patency duration was also similar between the two groups (60 vs. 68 days; P = 0.396). The median patient survival was longer in the plastic stent group than in the SEMS group (123 vs. 48 days; P = 0.005). CONCLUSIONS SEMSs were not superior to plastic stents for the palliation of malignant biliary obstruction in HCC with regard to successful drainage, stent patency, and adverse events. Patient survival was better in the plastic stent group. Given the lower cost, plastic stents could be a favorable option for malignant biliary obstruction caused by HCC.


Gut and Liver | 2017

Efficacy of Capecitabine Plus Oxaliplatin Combination Chemotherapy for Advanced Pancreatic Cancer after Failure of First-Line Gemcitabine-Based Therapy

Kwang Hyun Chung; Ji Kon Ryu; Jun Hyuk Son; Jae Woo Lee; Dong Kee Jang; Sang Hyub Lee; Yong-Tae Kim

Background/Aims Second-line chemotherapy in patients with advanced pancreatic ductal adenocarcinoma (PDAC) that progresses following gemcitabine-based treatment has not been established. This study aimed to investigate the efficacy and safety of second-line combination chemotherapy with capecitabine and oxaliplatin (XELOX) in these patients. Methods Between August 2011 and May 2014, all patients who received at least one cycle of XELOX (capecitabine, 1,000 mg/m2 twice daily for 14 days; oxaliplatin, 130 mg/m2 on day 1 of a 3-week cycle) combination chemotherapy for unresectable or recurrent PDAC were retrospectively recruited. The response was evaluated every 9 weeks, and the tumor response rate, progression-free survival and overall survival, and adverse events were assessed. Results Sixty-two patients were included; seven patients (11.3%) had a partial tumor response, and 20 patients (32.3%) had stable disease. The median progression-free and overall survival were 88 days (range, 35.1 to 140.9 days) and 158 days (range, 118.1 to 197.9 days), respectively. Patients who remained stable longer with frontline therapy (≥120 days) exhibited significantly longer progression-free and overall survival. The most common grade 3 to 4 adverse events in patients were vomiting (8.1%) and anorexia (6.5%). There was one treatment-related mortality caused by severe neutropenia and typhlitis. Conclusions Second-line XELOX combination chemotherapy demonstrated an acceptable response and survival rate in patients with advanced PDAC who had failed gemcitabine-based chemotherapy.

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Sang Hyub Lee

Seoul National University Hospital

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Ji Kon Ryu

Seoul National University Hospital

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Yong-Tae Kim

Seoul National University Hospital

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Dong Kee Jang

Seoul National University

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Ban Seok Lee

Seoul National University Hospital

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Jin Myung Park

Seoul National University

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Jae Min Lee

Seoul National University

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Yong Tae Kim

Korea Institute of Science and Technology

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Joo Kyung Park

Seoul National University

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