Weon Jin Ko

Gastroesophageal reflux after peroral endoscopic myotomy: a multicenter case–control study

Background and study aims The variables associated with gastroesophageal reflux (GER) after peroral endoscopic myotomy (POEM) are largely unknown. This study aimed to: 1) identify the prevalence of reflux esophagitis and asymptomatic GER in patients who underwent POEM, and 2) evaluate patient and intraprocedural variables associated with post-POEM GER. Patients and methods All patients who underwent POEM and subsequent objective testing for GER (pH study with or without upper gastrointestinal [GI] endoscopy) at seven tertiary academic centers (one Asian, two US, four European) were included. Patients were divided into two groups: 1) DeMeester score ≥ 14.72 (cases) and 2) DeMeester score of < 14.72 (controls). Asymptomatic GER was defined as a patient with a DeMeester score ≥ 14.72 who was not consuming proton pump inhibitor (PPI). Results A total of 282 patients (female 48.2 %, Caucasian 84.8 %; mean body mass index 24.1 kg/m2) were included. Clinical success was achieved in 94.3 % of patients. GER evaluation was completed after a median follow-up of 12 months (interquartile range 10 - 24 months). A DeMeester score of ≥ 14.72 was seen in 57.8 % of patients. Multivariable analysis revealed female sex to be the only independent association (odds ratio 1.69, 95 % confidence interval 1.04 - 2.74) with post-POEM GER. No intraprocedural variables were associated with GER. Upper GI endoscopy was available in 233 patients, 54 (23.2 %) of whom were noted to have reflux esophagitis (majority Los Angeles Grade A or B). GER was asymptomatic in 60.1 %. Conclusion Post-POEM GER was seen in the majority of patients. No intraprocedural variables were identified to allow for potential alteration in procedural technique.

Current Techniques for Treating Gastrointestinal Stromal Tumors in the Upper Gastrointestinal Tract

Most gastrointestinal stromal tumors (GISTs) arise from the proper muscle layer of the upper gastrointestinal (GI) tract and have a low malignant potential. They are sometimes accompanied by symptoms, but in most cases are detected by chance. Endoscopic surgery of subepithelial tumors in the upper GI tract has been actively performed, and its merits include the need for fewer medical devices compared with other surgical procedures and post-resection organ preservation. However, because endoscopic procedures are still limited to small or pilot studies, a multidisciplinary approach combining laparoscopy and endoscopy is needed for more effective and pathologically acceptable management of GISTs. Many new endoscopic surgeries have been developed, and this review describes the current status of and the new approaches for endoscopic surgery of GISTs in the upper GI tract.

Endoscopic Treatment of Various Gastrointestinal Tract Defects with an Over-the-Scope Clip: Case Series from a Tertiary Referral Hospital

Recently, increasingly invasive therapeutic endoscopic procedures and more complex gastrointestinal surgeries such as endoscopic mucosal resection, endoscopic submucosal dissection, and novel laparoscopic approaches have resulted in endoscopists being confronted more frequently with perforations, fistulas, and anastomotic leakages, for which nonsurgical closure is desired. In this article, we present our experiences with the use of over-the-scope clip (OTSC) for natural orifice transluminal endoscopic surgery (NOTES) closure, prevention of perforation, anastomotic leakages, and fistula closures. The OTSC is a valuable device for closing intestinal perforations and fistulas, for NOTES closure, and for the prevention of perforation after the excision of a tumor from the proper muscle layer. Furthermore, it seems to be quite safe to perform, even by endoscopists with little experience of the technique.

Comparison of the Outcomes of Peroral Endoscopic Myotomy for Achalasia According to Manometric Subtype

Background/Aims We evaluated whether manometric subtype is associated with treatment outcome in patients with achalasia treated by peroral endoscopic myotomy (POEM). Methods High-resolution manometry data and Eckardt scores were collected from 83 cases at two tertiary referral centers where POEM is performed. Manometric tracings were classified according to the three Chicago subtypes. Results Among the 83 cases, 48 type I, 24 type II, and 11 type III achalasia cases were identified. No difference was found in pre-POEM Eckardt score, basal lower esophageal sphincter (LES) pressure, or integrated relaxation pressure (IRP) among the type I, type II, and type III groups. All three patient groups showed a significant improvement in post-POEM Eckardt score (6.1±2.1 to 1.5±1.5, p=0.001; 6.8±2.2 to 1.2±0.9, p=0.001; 6.6±2.0 to 1.6±1.4, p=0.011), LES pressure (26.1±13.8 to 15.4±6.8, p=0.018; 32.3±19.0 to 19.2±10.4, p=0.003; 36.8±19.2 to 17.5±9.7, p=0.041), and 4s IRP (21.5±11.7 to 12.0±8.7, p=0.007; 24.5±14.8 to 12.0±7.6, p=0.002; 24.0±15.7 to 11.8±7.1, p=0.019) at a median follow-up of 16 months. Conclusions POEM resulted in a good clinical outcome for all manometric subtypes.

Evaluation and Endoscopic Management of Esophageal Submucosal Tumor

Submucosal tumors (SMTs) originate from tissues that constitute the submucosal layer and muscularis propria, and are covered by normal mucosa. Esophageal SMTs are rare, accounting for <1% of all esophageal tumors. However, the recent widespread use of endoscopy has led to a rapid increase in incidental detection of SMTs in Korea. Esophageal SMTs are benign in ≥90% of cases, but the possibility of malignancies such as gastrointestinal stromal tumor and malignant leiomyosarcoma still exists. Therefore, patients undergo resection in the presence of symptoms or the possibility of a malignant tumor. For resection of esophageal SMTs, surgical resection was the only option available in case of possible malignancy, but minimally invasive surgery by endoscopic resection is becoming more preferable to surgical resection with the development of endoscopic ultrasonography, endoscopic techniques, and other devices.

Image Quality Analysis of Various Gastrointestinal Endoscopes: Why Image Quality Is a Prerequisite for Proper Diagnostic and Therapeutic Endoscopy

Arising from human curiosity in terms of the desire to look within the human body, endoscopy has undergone significant advances in modern medicine. Direct visualization of the gastrointestinal (GI) tract by traditional endoscopy was first introduced over 50 years ago, after which fairly rapid advancement from rigid esophagogastric scopes to flexible scopes and high definition videoscopes has occurred. In an effort towards early detection of precancerous lesions in the GI tract, several high-technology imaging scopes have been developed, including narrow band imaging, autofocus imaging, magnified endoscopy, and confocal microendoscopy. However, these modern developments have resulted in fundamental imaging technology being skewed towards red-green-blue and this technology has obscured the advantages of other endoscope techniques. In this review article, we have described the importance of image quality analysis using a survey to consider the diversity of endoscope system selection in order to better achieve diagnostic and therapeutic goals. The ultimate aims can be achieved through the adoption of modern endoscopy systems that obtain high image quality.

Endoscopic resection of early gastric cancer: current status and new approaches.

Endoscopic resection (ER) of early gastric cancer (EGC) has been an optimal treatment for selected patients. As endoscopic submucosal dissection (ESD) has been widely used for treatment of EGC, concerns have been asked to achieve curative resection for EGC while guaranteeing precise prediction of lymph node metastasis (LNM). Moreover, a new microscopic imaging for precise endoscopic diagnosis of EGC is introduced. This review covers the current status and new approaches of ER of EGC.

Novel 3D‐printing technique for caps to enable tailored therapeutic endoscopy

To evaluate the feasibility of a tailored endoscopic cap created using 3D‐printing technology that is customized according to esophagogastric lesions of each patient.

Double-Scope Peroral Endoscopic Myotomy (POEM) for Esophageal Achalasia: The First Trial of a New Double-Scope POEM

With the accumulation of clinical trials demonstrating its efficacy and safety, peroral endoscopic myotomy (POEM) has emerged as a less invasive treatment option for esophageal achalasia compared with laparoscopic Heller myotomy. However, the difficulty in determining the exact extent of myotomy, a critical factor associated with the success and safety of the procedure, remains a limitation. Although the various endoscopic landmarks and ancillary techniques have been applied, none of these has been proven sufficient. As a solution for this limitation, the double-scope POEM technique with a second endoscope to assure the exact length of the submucosal tunnel has been applied since 2014. Before double-scope POEM was introduced, the second endoscope was applied only to confirm the accuracy of the procedure. In the present study, we performed double-scope POEM in the treatment of esophageal achalasia through a novel procedure of simultaneous application of the second endoscope to assist in the conventional POEM procedure.

Clarithromycin resistance and female gender affect Helicobacter pylori eradication failure in chronic gastritis

Background/Aims The eradication rate of the first-line triple therapy (a proton pump inhibitor, clarithromycin, and amoxicillin) for Helicobacter pylori infection has gradually decreased in Korea. We evaluated whether clinical parameters, clarithromycin resistance, and CYP2C19 genotype can affect the eradication failure. Methods A total of 203 patients with H. pylori-positive chronic gastritis were consecutively enrolled. They received clarithromycin-based triple therapy for 7 days. A clarithromycin resistance test was performed by detection of A2142G and A2143G point mutations in H. pylori 23S rRNA. The CYP2C19 genotype was examined for polymorphism G681A of exon 5 and G636A of exon 4 by polymerase chain reaction with restriction fragment length polymorphism. Eradication was assessed by a 13C-urea breath test 4 weeks after treatment. Results Of 203 patients, 190 completed the study. The eradication rate was 64.0% according to intention-to-treat analysis and 68.4% by per-protocol analysis. CYP2C19 genotypes were identified as follows: 75 poor metabolizers, 75 intermediate metabolizers, and 40 rapid metabolizers. Nonetheless, this polymorphism was not significantly associated with eradication failure (p = 0.682). Clarithromycin resistance was detected in 33/190 patients (17.4%), and their eradication rate was zero. Clarithromycin resistance (odds ratio [OR], 19.13; 95% confidence interval [CI], 9.35 to 35.09) and female gender (OR, 1.73; 95% CI, 1.15 to 4.25) were significantly associated with eradication failure. The other clinical parameters such as age, cigarette smoking, alcohol intake, the body mass index, hypertension, and diabetes were not significantly associated with eradication. Conclusions Clarithromycin resistance and female gender are factors affecting H. pylori eradication failure in patients with chronic gastritis.