Development and External Validation of a Deep Learning Algorithm for Prognostication of Cardiovascular Outcomes

BACKGROUND AND OBJECTIVES: We aim to explore the additional discriminative accuracy of a deep learning (DL) algorithm using repeated-measures data for identifying people at high risk for cardiovascular disease (CVD), compared to Cox hazard regression.METHODS: Two CVD prediction models were developed from National Health Insurance Service-Health Screening Cohort (NHIS-HEALS): a Cox regression model and a DL model. Performance of each model was assessed in the internal and 2 external validation cohorts in Koreans (National Health Insurance Service-National Sample Cohort; NHIS-NSC) and in Europeans (Rotterdam Study). A total of 412,030 adults in the NHIS-HEALS; 178,875 adults in the NHIS-NSC; and the 4,296 adults in Rotterdam Study were included.RESULTS: Mean ages was 52 years (46% women) and there were 25,777 events (6.3%) in NHIS-HEALS during the follow-up. In internal validation, the DL approach demonstrated a C-statistic of 0.896 (95% confidence interval, 0.886–0.907) in men and 0.921 (0.908–0.934) in women and improved reclassification compared with Cox regression (net reclassification index [NRI], 24.8% in men, 29.0% in women). In external validation with NHIS-NSC, DL demonstrated a C-statistic of 0.868 (0.860–0.876) in men and 0.889 (0.876–0.898) in women, and improved reclassification compared with Cox regression (NRI, 24.9% in men, 26.2% in women). In external validation applied to the Rotterdam Study, DL demonstrated a C-statistic of 0.860 (0.824–0.897) in men and 0.867 (0.830–0.903) in women, and improved reclassification compared with Cox regression (NRI, 36.9% in men, 31.8% in women).CONCLUSIONS: A DL algorithm exhibited greater discriminative accuracy than Cox model approaches.TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02931500

Development and External Validation of a Deep Learning Algorithm for Prognostication of Cardiovascular Outcomes

BACKGROUND AND OBJECTIVES@#We aim to explore the additional discriminative accuracy of a deep learning (DL) algorithm using repeated-measures data for identifying people at high risk for cardiovascular disease (CVD), compared to Cox hazard regression.@*METHODS@#Two CVD prediction models were developed from National Health Insurance Service-Health Screening Cohort (NHIS-HEALS): a Cox regression model and a DL model. Performance of each model was assessed in the internal and 2 external validation cohorts in Koreans (National Health Insurance Service-National Sample Cohort; NHIS-NSC) and in Europeans (Rotterdam Study). A total of 412,030 adults in the NHIS-HEALS; 178,875 adults in the NHIS-NSC; and the 4,296 adults in Rotterdam Study were included.@*RESULTS@#Mean ages was 52 years (46% women) and there were 25,777 events (6.3%) in NHIS-HEALS during the follow-up. In internal validation, the DL approach demonstrated a C-statistic of 0.896 (95% confidence interval, 0.886–0.907) in men and 0.921 (0.908–0.934) in women and improved reclassification compared with Cox regression (net reclassification index [NRI], 24.8% in men, 29.0% in women). In external validation with NHIS-NSC, DL demonstrated a C-statistic of 0.868 (0.860–0.876) in men and 0.889 (0.876–0.898) in women, and improved reclassification compared with Cox regression (NRI, 24.9% in men, 26.2% in women). In external validation applied to the Rotterdam Study, DL demonstrated a C-statistic of 0.860 (0.824–0.897) in men and 0.867 (0.830–0.903) in women, and improved reclassification compared with Cox regression (NRI, 36.9% in men, 31.8% in women).@*CONCLUSIONS@#A DL algorithm exhibited greater discriminative accuracy than Cox model approaches.TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02931500

Colon Transit Time May Predict Inadequate Bowel Preparation in Patients With Chronic Constipation

BACKGROUND/AIMS: We evaluated whether colonic transit time (CTT) can predict the degree of bowel preparation in patients with chronic constipation undergoing scheduled colonoscopy in order to assist in the development of better bowel preparation strategies for these patients. METHODS: We analyzed the records of 160 patients with chronic constipation from March 2007 to November 2012. We enrolled patients who had undergone a CTT test followed by colonoscopy. We defined patients with a CTT > or =30 hours as the slow transit time (STT) group, and patients with a CTT 30 hours were at risk for inadequate bowel preparation. CTT measured prior to colonoscopy could be useful for developing individualized strategies for bowel preparation in patients with slow CTT, as these patients are likely to have inadequate bowel preparation.

Relationship between Tetrahydrobiopterin and Portal Hypertension in Patients with Chronic Liver Disease

Tetrahydrobiopterin (BH4) is an essential cofactor in NO synthesis by endothelial nitric oxide synthase (eNOS) enzymes. It has been previously suggested that reduced intrahepatic BH4 results in a decrease in intrahepatic NO and contributes to increased hepatic vascular resistance and portal pressure in animal models of cirrhosis. The main aim of the present study was to evaluate the relationship between BH4 and portal hypertension (PHT). One hundred ninety-three consecutive patients with chronic liver disease were included in the study. Liver biopsy, measurement of BH4 and hepatic venous pressure gradient (HVPG) were performed. Hepatic fibrosis was classified using the Laennec fibrosis scoring system. BH4 levels were determined in homogenized liver tissues of patients using a high performance liquid chromatography (HPLC) system. Statistical analysis was performed to evaluate the relationship between BH4 and HVPG, grade of hepatic fibrosis, clinical stage of cirrhosis, Child-Pugh class. A positive relationship between HVPG and hepatic fibrosis grade, clinical stage of cirrhosis and Child-Pugh class was observed. However, the BH4 level showed no significant correlation with HVPG or clinical features of cirrhosis. BH4 concentration in liver tissue has little relation to the severity of portal hypertension in patients with chronic liver disease.

The usefulness of non-invasive liver stiffness measurements in predicting clinically significant portal hypertension in cirrhotic patients: Korean data

BACKGROUND/AIMS: Liver stiffness measurement (LSM) has been proposed as a non-invasive method for estimating the severity of fibrosis and the complications of cirrhosis. Measurement of the hepatic venous pressure gradient (HVPG) is the gold standard for assessing the presence of portal hypertension, but its invasiveness limits its clinical application. In this study we evaluated the relationship between LSM and HVPG, and the predictive value of LSM for clinically significant portal hypertension (CSPH) and severe portal hypertension in cirrhosis. METHODS: LSM was performed with transient elastography in 59 consecutive cirrhotic patients who underwent hemodynamic HVPG investigations. CSPH and severe portal hypertension were defined as HVPG > or =10 and > or =12 mmHg, respectively. Linear regression analysis was performed to evaluate the relationship between LSM and HVPG. Diagnostic values were analyzed based on receiver operating characteristic (ROC) curves. RESULTS: A strong positive correlation between LSM and HVPG was observed in the overall population (r2=0.496, P or =10 mmHg) was 0.851, and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for an LSM cutoff value of 21.95 kPa were 82.5%, 73.7%, 86.8%, and 66.7%, respectively. The AUROC at prediction of severe portal hypertension (HVPG > or =12 mmHg) was 0.877, and the sensitivity, specificity, PPV, and NPV at LSM cutoff value of 24.25 kPa were 82.9%, 70.8%, 80.6%, and 73.9%, respectively. CONCLUSIONS: LSM exhibited a significant correlation with HVPG in patients with cirrhosis. LSM could be a non-invasive method for predicting CSPH and severe portal hypertension in Korean patients with liver cirrhosis.

Complete Endoscopic Resection of Very Early Stage Gastric Plasmacytoma

Gastric plasmacytomas are very rare, and most are not detected until the disease has progressed to an advanced stage. However, there have been recent reports of cases of early-stage gastric plasmacytoma, in which neoplastic cells are confined to the mucosa or submucosa. Here we report a case of a very early stage gastric plasmacytoma that was confined to the lamina propria of the gastric mucosa. The lesion was successfully and completely removed by endoscopic submucosal dissection, and the surveillance endoscopy showed no recurrence during the follow-up of 40 months. This report appears to be the first documented case of complete endoscopic removal of a primary gastric plasmacytoma.

A Case of a Pancreatic Intraductal Papillary Mucinous Neoplasm Forming Multiple Fistulas and Manifesting as Duodenal Ulcer Bleeding / 대한소화기내시경학회지

An intraductal papillary mucinous neoplasm (IPMN) of the pancreas is an uncommon tumor characterized by the production of mucin in the pancreatic duct that occasionally involves the formation of fistulas with surrounding organs, including the stomach, duodenum and common bile duct. The mechanism underlying the formation of such fistulas is direct invasion by a tumor or a combination of high pressure in the main pancreatic duct and inflammatory stimulation. A 73-year-old man was referred to our hospital due to the presence of a gastric ulcer detected on screening gastroscopy. Endoscopic findings showed the presence of a whitish thick mucin coated ulcerative lesion that appeared as a perforation or fistula opening. Abdominal computed tomography and magnetic resonance cholangiopancreatography demonstrated the presence of an IPMN of the pancreas and multiple fistula formation with the neighboring organs. An endoscopic biopsy was carried out to obtain pancreatic tumor tissue through the pancreatogastric fistula and the mass was confirmed as a mucinous adenocarcinoma. To the best of our knowledge, this is the first case of an IPMN associated with a pancreatojejunal fistula and duodenal ulcer bleeding due to fistula formation.

The influence of vaccination on the clinical features of hemorrhagic fever with renal syndrome in the last 5 years / 대한내과학회지

BACKGROUND/AIMS: Hemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus is an endemic febrile disease in Korea. Although inactivated Hantaan virus vaccine has been introduced, the effect of vaccination is not clear. We evaluated the effect of vaccination on the incidence rate and clinical features of HFRS based on our clinical experience. METHODS: Group I consisted of the patients with confirmed HFRS from a total of 131 patients who were seropositive for Hantaan virus at one tertiary teaching hospital from January 2002 to December 2006. Group II contained 100 patients treated as HFRS at the same hospital from January 1986 to December 1990, before the introduction of the vaccine. Then, we compared the clinical features of the two groups. We confirmed whether the patients had been vaccinated by reviewing their medical records and from telephone interviews. RESULTS: Only 16 (12.2%) of the 131 patients who were seropositive for Hantaan virus were confirmed to have overt HFRS during the most recent 5 years. The incidence of overt HFRS was significantly lower in vaccinees (5%, 3 of 56) than in non-vaccinees (20%, 10 of 50) (p=0.025). The prevalence of renal failure (62.5 vs. 95%, p<0.001) and oliguria (6.25 vs. 46%, p=0.002) was significantly lower in group I than in group II. Three patients were treated with dialysis and none died in group I, versus 17 and 8, respectively, in group II. CONCLUSIONS: It appears that Hantaan virus vaccine has helped to reduce the amount of serious illness and the occurrence of HFRS.

A Case of Salmonella Infection in the Terminal Ileum That Was Initially Misdiagnosed as Lymphoma / 대한소화기내시경학회지

Salmonella usually invades the Peyer's patch of the terminal ileum or ascending colon. A 55-year old female was referred to our hospital for general weakness and sustained fever. On the abdominal contrast computed tomography (CT) scan, we found symmetric circular hypertrophy of the intestinal wall and multiple hypertrophied lymph nodes in the terminal ileum. The positron emission tomography computed tomography (PET-CT) scan showed skipped areas of wall thickening and intense fluorodeoxyglucose (FDG) uptake in the terminal ileum and the ileocecal valve with adjacent lymphadenopathies. On the colonoscopy, multiple mass forming variable-sized ulcers on the terminal ileum were found, so a biopsy specimen and the colonic luminal fluid were obtained, and we made a diagnosis of lymphoma. However, the blood and colonic luminal fluid culture for Salmonella paratyphi-A was reported as positive, and therefore we corrected the diagnosis to Salmonella infection. We report here on a case of Salmonella infection in the terminal ileum, which looked like malignant lymphoma on the baseline radiologic image studies, including the CT and PET-CT.

Two Cases of Benign and Malignant Lesion Caused Ileocolic Intussusception: Preoperative Colonoscopic Reduction was Attempted for These Patients / 대한소화기내시경학회지

In contrast to the idiopathic cause of intussusception in children, adult intussusception in most patients is associated with organic causes. The majority of these patients are brought to the operating room with the preoperative diagnosis of bowel obstruction, and the surgeon discovers an intussusception intraoperatively. But the increasing use of abdominal CT may improve the ability to diagnose intussusception. There is no universal agreement upon the correct treatment of adult intussusception, although most authors agree that surgical intervention is necessary. In the more recent reports, colonoscopic reduction of intussusception has been reported for selected patients. For patients in whom the involved ileum is extremely long, it is advisable to attempt an operative reduction or colonoscopic reduction selectively. Thus, we report here on two patients with benign and malignant lesion, respectively, that caused ileocolic intussusception; preoperative colonoscopic diagnosis and reduction were attempted for these patients, although the patients were not reduced by colonoscopic procedure.