Background/Aims: The use of a self-expandable metal stent (SEMS) is recommended for unresectable malignant biliary obstruction (MBO). Stent-related adverse events might differ according to the position of the stent through the ampulla of Vater (AOV). We retrospectively evaluated SEMS patency and adverse events according to the position of the SEMS. Methods: In total, 280 patients who underwent endoscopic SEMS placement due to malignant distal biliary obstruction were analyzed retrospectively. Suprapapillary and transpapillary SEMS insertions were performed on 51 patients and 229 patients, respectively. Results: Between the suprapapillary group (SPG) and transpapillary group (TPG), the stent patency period was not significantly different (median [95% confidence interval]: 107 days [82.3 to 131.7] vs 120 days [99.3 to 140.7], p=0.559). There was also no significant difference in the rate of adverse events. In subgroup analysis, the stent patency for an MBO located within 2 cm from the AOV was found to be significantly shorter than that for an MBO located more than 2 cm from the AOV in the SPG (64 days [0 to 160.4] vs 127 days [82.0 to 171.9], p<0.001) and TPG (87 days [52.5 to 121.5] vs 130 [97.0 to 162.9], p<0.001). Patients with an MBO located within 2 cm from the AOV in both groups had a higher percentage of duodenal invasion (SPG: 40.0% vs 4.9%, p=0.002; TPG: 28.6% vs 2.9%, p<0.001) than patients with an MBO located more than 2 cm from the AOV. Conclusions The SPG and TPG showed similar results in terms of stent patency and rate of adverse events. However, patients with an MBO located within 2 cm from the AOV had a higher percentage of duodenal invasion with shorter stent patency than those with an MBO located more than 2 cm from the AOV, regardless of stent position.

Background: Fractional flow reserve (FFR) based on computed tomography (CT) has been shown to better identify ischemia-causing coronary stenosis. However, this current technology requires high computational power, which inhibits its widespread implementation in clinical practice. This prospective, multicenter study aimed at validating the diagnostic performance of a novel simple CT based fractional flow reserve (CT-FFR) calculation method in patients with coronary artery disease. Methods: Patients who underwent coronary CT angiography (CCTA) within 90 days and invasive coronary angiography (ICA) were prospectively enrolled. A hemodynamically significant lesion was defined as an FFR ≤ 0.80, and the area under the receiver operating characteristic curve (AUC) was the primary measure. After the planned analysis for the initial algorithm A, we performed another set of exploratory analyses for an improved algorithm B. Results: Of 184 patients who agreed to participate in the study, 151 were finally analyzed.Hemodynamically significant lesions were observed in 79 patients (52.3%). The AUC was 0.71 (95% confidence interval [CI], 0.63–0.80) for CCTA, 0.65 (95% CI, 0.56–0.74) for CT-FFR algorithm A (P = 0.866), and 0.78 (95% CI, 0.70–0.86) for algorithm B (P = 0.112). Diagnostic accuracy was 0.63 (0.55–0.71) for CCTA alone, 0.66 (0.58–0.74) for algorithm A, and 0.76 (0.68–0.82) for algorithm B. Conclusion This study suggests the feasibility of automated CT-FFR, which can be performed on-site within several hours. However, the diagnostic performance of the current algorithm does not meet the a priori criteria for superiority. Future research is required to improve the accuracy.

Purpose: This study evaluates the radiation shielding performance of a new lead-free tungsten-based sheet to reduce the radiation exposure of operators and patients under C-arm fluoroscopy. Materials and Methods: A non-lead radiation shielding sheet (ROO201128; Pentas, Korea) was fabri-cated using tungsten and bismuth. The dose measurements were conducted using a C-arm fluoroscopy machine at 64 kVp and 1.5 mA, assuming two possible scenarios according to the position of the sheet. In each scenario, measurements were conducted at three distances (30, 60, and 90 cm) away from the beam center and in three directions (cephal, caudal, and operator’s direction). Results: In the area within a radius of 60 cm from the beam center, the measured doses were reduced by 66.3% on mean, and the doses measured at distances more than 60 cm were less than 0.1 mSv/h in both scenarios. The most beneficial utilization of the lead-free shielding sheet was verified during C-arm fluoroscopy by placing the sheet on the X-ray tube. The operator’s radiation exposure was reduced by 56.6% when the sheet was placed under the phantom, and by 81.0% when the sheet was placed on the X-ray tube. Conclusion The use of lead-free radiation shielding sheets under C-arm fluoroscopy was effective in reducing radiation exposure, and the most beneficial scenario in which the sheet can be utilized was verified when the sheet was placed on the X-ray tube.

BACKGROUND: The repair of large bone defects remains a significant challenge in clinical practice and requires bone grafts or substitute materials. In this study, we developed a unique hybrid bone scaffold comprising a three dimensional (3D)-printed metal plate for weight bearing and a biodegradable polymer tube serving as bone conduit. We assessed the long-term effect of the hybrid bone scaffold in repairing radial bone defects in a beagle model. METHODS: Bone defects were created surgically on the radial bone of three beagle dogs and individually-tailored scaffolds were used for reconstruction with or without injection of autologous bone and decellularized extracellular matrix (dECM). The repaired tissue was evaluated by X-ray, micro-computed tomography, and histological observation 6 months after surgery. The functional integrity of hybrid bone scaffold-mediated reconstructions was assessed by gait analysis. RESULTS: In vivo analysis showed that the hybrid bone scaffolds maintained the physical space and bone conductivity around the defect. New bone was formed adjacent to the scaffolds. Addition of autologous bone and dECM in the polymer tube improved healing by enhancing bone induction and osteoconduction. Furthermore, the beagles’ gait appeared normal by 4 months. CONCLUSION The future of bone healing and regeneration is closely related to advances in tissue engineering. Bone production using autologous bone and dECM loaded on 3D-printed hybrid bone scaffolds can successfully induce osteogenesis and provide mechanical force for functional bone regeneration, even in large bone defects.

Concerns about the effectiveness of current vaccines against the rapidly spreading severe acute respiratory syndrome-coronavirus-2 omicron (B.1.1.529) variant are increasing. This study aimed to assess neutralizing antibody activity against the wild-type (BetaCoV/Korea/ KCDC03/2020), delta, and omicron variants after full primary and booster vaccinations with BNT162b2. A plaque reduction neutralization test was employed to determine 50% neutralizing dilution (ND 50 ) titers in serum samples. ND 50 titers against the omicron variant (median [interquartile range], 5.3 [< 5.0–12.7]) after full primary vaccination were lower than those against the wild-type (144.8 [44.7–294.0]) and delta (24.3 [14.3–81.1]) variants.Furthermore, 19/30 participants (63.3%) displayed lower ND 50 titers than the detection threshold (< 10.0) against omicron after full primary vaccination. However, the booster vaccine significantly increased ND 50 titers against BetaCoV/Korea/KCDC03/2020, delta, and omicron, although titers against omicron remained lower than those against the other variants (P < 0.001). Our study suggests that booster vaccination with BNT162b2 significantly increases humoral immunity against the omicron variant.

Background/Aims: Sepsis-3 criteria and quick Sequential Organ Failure Assessment (qSOFA) have been advocated to be used in defining sepsis in the general population. We aimed to compare the Sepsis-3 criteria and Chronic Liver Failure-SOFA (CLIF-SOFA) scores as predictors of in-hospital mortality in cirrhotic patients admitted to the emergency department (ED) for infections. Methods: A total of 1,622 cirrhosis patients admitted at the ED for infections were assessed retrospectively. We analyzed their demographic, laboratory, and microbiological data upon diagnosis of the infection. The primary endpoint was inhospital mortality rate. The predictive performances of baseline CLIF-SOFA, Sepsis-3, and qSOFA scores for in-hospital mortality were evaluated. Results: The CLIF-SOFA score proved to be significantly better in predicting in-hospital mortality (area under the receiver operating characteristic curve [AUROC], 0.80; 95% confidence interval [CI], 0.78–0.82) than the Sepsis-3 (AUROC, 0.75; 95% CI, 0.72–0.77, P<0.001) and qSOFA (AUROC, 0.67; 95% CI, 0.64–0.70; P<0.001) score. The CLIF-SOFA, CLIF-C-AD scores, Sepsis-3 criteria, septic shock, and qSOFA positivity were significantly associated with in-hospital mortality (adjusted hazard ratio [aHR], 1.24; 95% CI, 1.19–1.28; aHR, 1.13; 95% CI, 1.09–1.17; aHR, 1.19; 95% CI, 1.15–1.24; aHR, 1.88; 95% CI, 1.42–2.48; aHR, 2.06; 95% CI, 1.55–2.72; respectively; all P<0.001). For CLIF-SOFA scores ≥6, in-hospital mortality was >10%; this is the cutoff point for the definition of sepsis. Conclusions Among cirrhosis patients presenting with infections at the ED, CLIF-SOFA scores showed a better predictive performance for mortality than both Sepsis-3 criteria and qSOFA scores, and can be a useful tool of risk stratification in cirrhotic patients requiring timely intervention for infection.

The recent novel coronavirus disease 2019 (COVID-19) pandemic has led to unprecedented changes in behavior. We evaluated the current status of precautionary behavior and physical activity in chronic kidney disease (CKD) patients during the COVID-19 pandemic. Methods: A population of CKD patients (n = 306) registered in the Study on Kidney Disease and Environmental Chemicals (SKETCH, Clinical Trial No. NCT04679168) cohort recruited from June 2020 to October 2020 was included in the study. We conducted a questionnaire survey related to risk perception of COVID-19, precautionary behavior, and physical activity. Results: There were 187 patients (61.1%) with estimated glomerular filtration rate of <45 mL/min/1.73 m2 . This population showed a higher degree of risk perception for COVID-19 than the general population. Age was the most significant determinant of risk perception among CKD patients. During the pandemic, social distancing and hygiene-related behavior were significantly increased (p < 0.001). The frequency of exercise was decreased only in those who took regular exercise, without diabetes, or with a lower Charlson comorbidity index (CCI) (p < 0.001), with no change among the other groups. Socioeconomic status and comorbidities significantly affected behavioral characteristics regardless of the category. Education and income were significantly associated with precautionary behaviors such as staying at home and hand sanitizer use. Patients with higher CCI status significantly increased frequency of exercise (adjusted odds ratio, 2.10; 95% confidence interval, 1.01–4.38). Conclusion: CKD patients showed higher risk perception with active precautionary behavioral changes than the general population. Healthcare providers should be aware of the characteristics to comprise precautionary behavior without reducing physical activity.

Background/Aims: Although it is near concluded that renin-angiotensin system inhibitors do not have a harmful effect on coronavirus disease 2019 (COVID-19), there is no report about whether angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs) offer any protective role. This study aimed to compare the association of ARBs and ACEIs with COVID-19-related mortality. Methods: All patients with COVID-19 in Korea between January 19 and April 16, 2020 were enrolled. The association of ARBs and ACEIs with mortality within 60 days were evaluated. A comparison of hazard ratio (HR) was performed between COVID-19 patients and a retrospective cohort of pneumonia patients hospitalized in 2019 in Korea. Results: Among 10,448 COVID-19 patients, ARBs and ACEIs were prescribed in 1,231 (11.7%) and 57 (0.6%) patients, respectively. After adjusting for age, sex, and history of comorbidities, the ARB group showed neutral association (HR, 1.034; 95% CI, 0.765 to 1.399; p = 0.8270) and the ACEI groups showed no significant associations likely owing to the small population size (HR, 0.736; 95% CI, 0.314 to 1.726; p = 0.4810). When comparing HR between COVID-19 patients and a retrospective cohort of patients hospitalized with pneumonia in 2019, the trend of ACEIs showed similar benefits, whereas the protective effect of ARBs observed in the retrospective cohort was absent in COVID-19 patients. Meta-analyses showed significant positive correlation with survival of ACEIs, whereas a neutral association between ARBs and mortality. Conclusions Although ARBs or ACEIs were not associated with fatal outcomes, potential beneficial effects of ARBs observed in pneumonia were attenuated in COVID-19.

Background/Aims: Although it is near concluded that renin-angiotensin system inhibitors do not have a harmful effect on coronavirus disease 2019 (COVID-19), there is no report about whether angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs) offer any protective role. This study aimed to compare the association of ARBs and ACEIs with COVID-19-related mortality. Methods: All patients with COVID-19 in Korea between January 19 and April 16, 2020 were enrolled. The association of ARBs and ACEIs with mortality within 60 days were evaluated. A comparison of hazard ratio (HR) was performed between COVID-19 patients and a retrospective cohort of pneumonia patients hospitalized in 2019 in Korea. Results: Among 10,448 COVID-19 patients, ARBs and ACEIs were prescribed in 1,231 (11.7%) and 57 (0.6%) patients, respectively. After adjusting for age, sex, and history of comorbidities, the ARB group showed neutral association (HR, 1.034; 95% CI, 0.765 to 1.399; p = 0.8270) and the ACEI groups showed no significant associations likely owing to the small population size (HR, 0.736; 95% CI, 0.314 to 1.726; p = 0.4810). When comparing HR between COVID-19 patients and a retrospective cohort of patients hospitalized with pneumonia in 2019, the trend of ACEIs showed similar benefits, whereas the protective effect of ARBs observed in the retrospective cohort was absent in COVID-19 patients. Meta-analyses showed significant positive correlation with survival of ACEIs, whereas a neutral association between ARBs and mortality. Conclusions Although ARBs or ACEIs were not associated with fatal outcomes, potential beneficial effects of ARBs observed in pneumonia were attenuated in COVID-19.

Purpose: The clinical implications of tumor-infiltrating T cell subsets and their spatial distribution in biliary tract cancer (BTC) patients treated with gemcitabine plus cisplatin were investigated. Materials and Methods: A total of 52 BTC patients treated with palliative gemcitabine plus cisplatin were included. Multiplexed immunohistochemistry was performed on tumor tissues, and immune infiltrates were separately analyzed for the stroma, tumor margin, and tumor core. Results: The density of CD8+ T cells, FoxP3- CD4+ helper T cells, and FoxP3+ CD4+ regulatory T cells was significantly higher in the tumor margin than in the stroma and tumor core. The density of LAG3- or TIM3-expressing CD8+ T cell and FoxP3- CD4+ helper T cell infiltrates was also higher in the tumor margin. In extrahepatic cholangiocarcinoma, there was a higher density of T cell subsets in the tumor core and regulatory T cells in all regions. A high density of FoxP3- CD4+ helper T cells in the tumor margin showed a trend toward better progression-free survival (PFS) (p=0.092) and significantly better overall survival (OS) (p=0.012). In multivariate analyses, a high density of FoxP3- CD4+ helper T cells in the tumor margin was independently associated with favorable PFS and OS. Conclusion The tumor margin is the major site for the active infiltration of T cell subsets with higher levels of LAG3 and TIM3 expression in BTC. The density of tumor margin-infiltrating FoxP3- CD4+ helper T cells may be associated with clinical outcomes in BTC patients treated with gemcitabine plus cisplatin.