Kyong Joo Lee

Application of a wavelet adaptive filter to minimise distortion of the ST-segment.

A wavelet adaptive filter (WAF) for the removal of baseline wandering in ECG signals is described. The WAF consists of two parts. The first part is a wavelet transform that decomposes the ECG signal into seven frequency bands using Vaidyanathan-Hoang wavelets. The second part is an adaptive filter that uses the signal of the seventh lowest-frequency band among the wavelet transformed signals as primary input and a constant as reference input. To evaluate the performance of the WAF, two baseline wandering elimination filters are used, a commercial standard filter with a cutoff frequency of 0.5 Hz and a general adaptive filter. The MIT/BIH database and the European ST-T database are used for the evaluation. The WAF performs better in the average power of eliminated noise than the standard filter and adaptive filter. Furthermore, it shows a lower ST-segment distortion than the standard filter and the adaptive filter.

Serum CA 19-9 and CEA levels as a prognostic factor in pancreatic adenocarcinoma.

Purpose To investigate the use of pretreatment carbohydrate antigen (CA) 19-9 and carcinoembryonic antigen (CEA) as prognostic factors to determine survival in pancreatic adenocarcinoma. Materials and Methods A retrospective review of the medical records of patients who were diagnosed with pancreatic adenocarcinoma and received surgery, chemoradiotherapy or chemotherapy was performed. Factors, including CA 19-9 and CEA, associated with the survival of pancreatic cancer patients were analyzed. Results Patients with the median age of 65 years were included (n=187). Elevated serum CA 19-9 levels and CEA levels were observed in 75.4% and 39% of patients at diagnosis, respectively. CEA was correlated with tumor stages (p=0.005), but CA 19-9 was not. CA 19-9 and CEA were elevated in 69.0% and 33.3% of patients with resectable pancreatic cancer, and elevated in 72.9% and 47.2% of patients with advanced pancreatic cancer, respectively. The median overall survival of the normal serum CEA group was longer than that of the elevated serum CEA group (16.3 months vs. 10.2 months, p=0.004). However, the median overall survival of the normal serum CA 19-9 group was not different from that of the elevated serum CA 19-9 group (12.4 months vs. 13.5 months, p=0.969). The independent factors associated with overall survival were advanced pancreatic cancer [harzard ratio (HR) 4.33, p=0.001] and elevated serum CEA level (HR 1.52, p=0.032). Conclusion Patients with elevated serum CEA level at diagnosis demonstrated poor overall survival. Pretreatment CEA level may predict the prognosis of patients with pancreatic adenocarcinoma.

Risk Factors for Treatment Failure and Recurrence after Metronidazole Treatment for Clostridium difficile-associated Diarrhea

BACKGROUND/AIMS The incidence of treatment failure or recurrence of Clostridium difficile-associated diarrhea (CDAD) following metronidazole treatment has increased recently. We studied the treatment failure, recurrence rate, and risk factors predictive of treatment failure and recurrence after metronidazole treatment for CDAD. METHODS We retrospectively identified consecutive patients who were admitted and treated for CDAD at a single tertiary institution in Korea over a recent 10-year period (i.e., 1998-2008). RESULTS Metronidazole was administered as the initial treatment to 111 of 117 patients (94.9%) with CDAD. Fourteen patients (12.6%) had no clinical response to the metronidazole treatment, and in 13 patients (13.4%) CDAD recurred after successful metronidazole treatment. Diabetes mellitus (p=0.014) and sepsis (p=0.002) were independent risk factors for metronidazole treatment failure. Patients who had received surgery within 1 month before CDAD developed were more likely to experience a recurrence after metronidazole treatment (p=0.032). Vancomycin exhibited a higher response rate after treatment failure, and metronidazole showed a reasonable response rate in the treatment of recurrence. Treatment failure and recurrence rates increased with time after metronidazole treatment for CDAD over the 10-year study period. CONCLUSIONS Our data suggest that diabetes mellitus and sepsis are independent risk factors for metronidazole treatment failure, and that operation history within 1 month of development of CDAD is a predictor of a recurrence after metronidazole treatment.

Serum high mobility group box‐1 is a powerful diagnostic and prognostic biomarker for pancreatic ductal adenocarcinoma

Extracellular high mobility group box‐1 (HMGB1) contributes to tumor growth and invasiveness. We evaluated the diagnostic and prognostic ability of serum HMGB1 for pancreatic ductal adenocarcinoma (PDAC). Serum HMGB1 measured by enzyme‐linked immunosorbent assay (ELISA) were compared among normal, chronic pancreatitis, PDAC group in both training (n = 25, each group) and independent validation set (n = 45, each group). To determine the usability of serum HMGB1 as a diagnostic predictor of PDAC, receiver operating characteristic (ROC) curves with sensitivity/specificity and logistic regression were evaluated. To assess the HMGB1‐associated prognosis of PDAC, Kaplan–Meier survival and Cox proportional‐hazards regression were applied. Serum HMGB1 was correlated with presence and advanced‐stage of PDAC. Logistic regression exhibited serum HMGB1 was a remarkable biomarker to predict PDAC as a single or multiple‐markers; sensitivity/specificity of serum HMGB1 were superior to carbohydrate antigen (CA) 19‐9 or carcinoembryonic antigen (CEA) in both training and independent datasets. Kaplan–Meier survival analysis showed PDAC patients with high serum HMGB1 levels (>30 ng/mL; median survival, 192 days) had a worse prognosis than patients with low HMGB1 levels (≤30 ng/mL; 514 days) by log‐rank (P = 0.017). Cox proportional‐hazards model showed the relative hazard ratios in high‐serum HMGB1 group was 3.077 compared with the low‐serum HMGB1 group. In conclusion, serum HMGB1 is a desirable diagnostic and prognostic biomarker for PDAC compared with pre‐existing PDAC biomarkers, CA19‐9 and CEA.

Clinical advantages of a metal stent with an S-shaped anti-reflux valve in malignant biliary obstruction

Transpapillary stent insertion is the standard treatment for palliating malignant biliary obstruction. However, luminal occlusion often occurs due to sludge formation, tumor ingrowth, or tumor overgrowth. Currently, influx of duodenal contents by duodenobiliary reflux is considered a mechanism of stent obstruction. The aim of the present study was to evaluate the efficacy and safety of a metal stent with an anti‐reflux valve in distal malignant biliary obstruction.

Comparison of Predictive Systems in Severe Acute Pancreatitis According to the Revised Atlanta Classification.

Objectives We aimed to compare the prognostic value of various predictors and complex scoring systems for prediction of severe acute pancreatitis (SAP) according to the revised Atlanta classification. Methods C-reactive protein (CRP) and procalcitonin were obtained on admission, and CRP level 24 hours after admission (CRP2) was measured. Various scoring systems including Ranson, Acute Physiology and Chronic Health Examination (APACHE II), the Bedside Index for Severity in Acute Pancreatitis, and Computed Tomography Severity Index (CTSI) were calculated. Results There were 146 patients with acute pancreatitis (mean age, 50.6 ± 18.3 years; 63% male), of which 43 patients (29.5%) received a diagnosis of moderately severe AP, and 17 patients (11.6%) received a diagnosis of SAP. In patients with moderately severe acute pancreatitis to SAP, CTSI (odds ratio [OR], 10.46; 95% confidence interval [CI], 4.3–25.43; P < 0.001), APACHE II (OR, 3.87; 95% CI, 1.18–12.64; P = 0.025), and CRP2 (OR, 4.5; 95% CI, 1.53–13.1; P = 0.006) were strongly related to moderately severe acute pancreatitis and SAP. In patients with SAP compared with mild to moderately severe AP, procalcitonin (OR, 4.36; 95% CI, 1.01–18.96; P = 0.049) was the only factor strongly associated with SAP. Conclusions Procalcitonin was the best predictor for patients with SAP; CTSI, APACHE II, and CRP2 were valuable predictors for patients with moderately severe acute pancreatitis and SAP.

Dose escalation in locally advanced pancreatic cancer patients receiving chemoradiotherapy

PURPOSE To investigate whether radiotherapy (RT) dose escalation would improve treatment outcomes without increasing severe toxicity in locally advanced pancreatic cancer patients. METHODS From 2005 to 2015, 497 locally advanced pancreatic cancer patients who received neoadjuvant or definitive chemoradiotherapy (CCRT) were included. Patients were divided according to the total dose (TD). Overall survival (OS), progression-free survival (PFS), local failure-free rate (LFFR), distant failure-free rate (DFFR), and toxicity rates were compared between <61Gy (n=345) and ≥61Gy groups (n=152). Additionally, propensity score matching was performed. RESULTS At a median follow-up of 19.3months (range, 4.8-128.5months), the 1-year OS, PFS, LFFR, and DFFR were significantly higher in the ≥61Gy group. After multivariate analysis, a TD of ≥61Gy remained a significant favorable factor for OS (p=0.019), PFS (p=0.001), LFFR (p=0.004), and DFFR (p=0.008). After propensity score matching, the ≥61Gy group still showed higher OS, PFS, and LFFR, but not DFFR (p=0.205). The acute and late toxicity rates showed no significant difference between the two groups. CONCLUSION Patients who received a higher RT dose showed not only improved PFS and LFFR, but also improved OS without an increase in severe toxicity. Dose-escalated CCRT can be a favorable treatment option in locally advanced pancreatic cancer patients.

High Dietary Sodium Intake Assessed by Estimated 24-h Urinary Sodium Excretion Is Associated with NAFLD and Hepatic Fibrosis.

Background Although high sodium intake is associated with obesity and hypertension, few studies have investigated the relationship between sodium intake and non-alcoholic fatty liver disease (NAFLD). We evaluated the association between sodium intake assessed by estimated 24-h urinary sodium excretion and NAFLD in healthy Koreans. Methods We analyzed data from 27,433 participants in the Korea National Health and Nutrition Examination Surveys (2008–2010). The total amount of sodium excretion in 24-h urine was estimated using Tanaka’s equations from spot urine specimens. Subjects were defined as having NAFLD when they had high scores in previously validated NAFLD prediction models such as the hepatic steatosis index (HSI) and fatty liver index (FLI). BARD scores and FIB-4 were used to define advanced fibrosis in subjects with NAFLD. Results The participants were classified into three groups according to estimated 24-h urinary excretion tertiles. The prevalence of NAFLD as assessed by both FLI and HSI was significantly higher in the highest estimated 24-h urinary sodium excretion tertile group. Even after adjustment for confounding factors including body fat and hypertension, the association between higher estimated 24-h urinary sodium excretion and NAFLD remained significant (Odds ratios (OR) 1.39, 95% confidence interval (CI) 1.26–1.55, in HSI; OR 1.75, CI 1.39–2.20, in FLI, both P < 0.001). Further, subjects with hepatic fibrosis as assessed by BARD score and FIB-4 in NAFLD patients had higher estimated 24-h urinary sodium values. Conclusions High sodium intake was independently associated with an increased risk of NAFLD and advanced liver fibrosis.

Electrolyte changes after bowel preparation for colonoscopy: A randomized controlled multicenter trial

AIM To investigate the electrolyte changes between 2-L polyethylene glycol with ascorbic acid 20 g (PEG-Asc) and 4-L PEG solutions. METHODS From August 2012 to February 2013, a total of 226 patients were enrolled at four tertiary hospitals. All patients were randomly allocated to a PEG-Asc group or a 4-L PEG. Before colonoscopy, patients completed a questionnaire to assess bowel preparation-related symptoms, satisfaction, and willingness. Endoscopists assessed the bowel preparation using the Boston Bowel Preparation Scale (BBPS). In addition, blood tests, including serum electrolytes, serum osmolarity, and urine osmolarity were evaluated both before and after the procedure. RESULTS A total of 226 patients were analyzed. BBPS scores were similar and the adequate bowel preparation rate (BBPS ≥ 6) was not different between the two groups (PEG-Asc vs 4-L PEG, 73.2% vs 76.3%, P = 0.760). Bowel preparation-related symptoms also were not different between the two groups. The taste of PEG-Asc was better (41.1% vs 16.7%, P < 0.001), and the willingness to undergo repeated bowel preparation was higher in the PEG-Asc group (73.2% vs 59.3%, P = 0.027) than in 4-L PEG. There were no significant changes in serum electrolytes in either group. CONCLUSION In this multicenter trial, bowel preparation with PEG-Asc was better than 4-L PEG in terms of patient satisfaction, with similar degrees of bowel preparation and electrolyte changes.

A Comparison of Gastrointestinal Toxicities between Intensity-Modulated Radiotherapy and Three-Dimensional Conformal Radiotherapy for Pancreatic Cancer.

Background/Aims Concurrent chemoradiotherapy (CCRT) is considered the treatment option for locally advanced pancreatic cancer, but accompanying gastrointestinal toxicities are the most common complication. With the introduction of three-dimensional conformal radiotherapy (3-D CRT) and intensity-modulated radiotherapy (IMRT), CCRT-related adverse events are expected to diminish. Here, we evaluated the benefits of radiation modalities by comparing gastrointestinal toxicities between 3-D CRT and IMRT. Methods Patients who received CCRT between July 2010 and June 2012 in Severance Hospital, Yonsei University College of Medicine, were enrolled prospectively. The patients underwent upper endoscopy before and 1 month after CCRT. Results A total of 84 patients were enrolled during the study period. The radiotherapy modalities delivered included 3D-CRT (n=40) and IMRT (n=44). The median follow-up period from the start of CCRT was 10.6 months (range, 3.8 to 29.9 months). The symptoms of dyspepsia, nausea/vomiting, and diarrhea did not differ between the groups. Upper endoscopy revealed significantly more gastroduodenal ulcers in the 3-D CRT group (p=0.003). The modality of radiotherapy (3D-CRT; odds ratio [OR], 11.67; p=0.011) and tumor location (body of pancreas; OR, 11.06; p=0.009) were risk factors for gastrointestinal toxicities. Conclusions IMRT is associated with significantly fewer gastroduodenal injuries among patients treated with CCRT for pancreatic cancer.