Roberto Oleas

Instituto Ecuatoriano de Enfermedades Digestivas · Gastroenterology and Endoscopy Division

Background: Endoscopic ultrasound (EUS)-guided gastroenterostomy (EUS-GE) is a minimally invasive therapy for patients with gastric outlet obstruction without the risks of surgical bypass and the limited long-term efficacy of enteral self-expanding metal stent placement. However, due to its novelty, there is a lack of significant data comparing lo...

Introduction and Objectives: The diagnostic work-up of chronic liver disease includes less invasive procedures such as transient elastography (TE), abdominal ultrasonography, esophagogastroduodenoscopy, and more invasive procedures, mainly portal gradient pressure measurement and liver biopsy. Endoscopic ultrasound (EUS) recently included shear-wav...

Background: Chronic esophageal conditions (CEC) are associated with significant disease-related burden, disability, and costs. Health-related quality of life (HRQOL) constructs are intended to capture the physical, mental, social, and emotional aspects of a patient's life and how health status impacts these domains. The Northwestern Esophageal Qua...

Background and aims Patients with distal malignant biliary obstruction (MBO) and cystic duct orifice tumoral involvement have an increased risk of developing acute cholecystitis following self-expandable metallic stent (SEMS) placement. We aimed to determine whether primary endoscopic ultrasound (EUS)-guided gallbladder drainage prevents the occurr...

Background: Endoscopic ultrasound (EUS) can detect small lesions throughout the digestive tract; however, it remains challenging to accurately identify malignancies with this approach. EUS elastography measures tissue hardness, by which malignant and nonmalignant pancreatic masses (PMs) and lymph nodes (LNs) can be differentiated. However, there i...

Background and study aims Probe-based confocal laser endomicroscopy (pCLE) can provide high magnification to evaluate chronic atrophic gastritis (CAG), but the current pCLE criteria are qualitative and prone to variability. We aimed to propose a quantitative CAG criterion based on pCLE to distinguish non-atrophic gastritis (NAG) from CAG. Patients...

Background: Currently, there is insufficient data about the accuracy in the diagnosing of pancreatic cystic lesions (PCLs), especially with novel endoscopic techniques such as with direct intracystic micro-forceps biopsy (mFB) and needle-based confocal laser-endomicroscopy (nCLE). Aim: To compare the accuracy of endoscopic ultrasound (EUS) and a...

Video 1EUS-guided microwave ablation of an unresectable pancreatic mass using a novel generator platform and a specialized 19.5-gauge needle antenna.

Background Endoscopic ultrasound (EUS)-guided drainage of pancreatic fluid collections (PFCs) by cautery-enhanced lumen-apposing metal stents (LAMS) has largely been limited to collections located < 10 mm from the luminal wall. We present outcomes of the use of a novel 15-mm-long cautery-enhanced LAMS for drainage of PFCs located ≥ 10 mm away. Meth...

Gastric variceal bleeding has a high mortality. Endoscopic cyanoacrylate injection is the standard therapy; however, rebleeding and unexpected adverse events, such as injection sites ulcers and distal glue embolisms, are pitfalls of this therapy. Endoscopic ultrasound (EUS)-guided endovascular therapies offer a safer and more practical alternative...

Background and Aims Digital single-operator cholangioscopy (DSOC) allows direct visualization of the biliary tree for evaluation of biliary strictures. Our objective was to assess the interobserver agreement (IOA) of DSOC interpretation for indeterminate biliary strictures using newly refined criteria. Methods Fourteen endoscopists were asked to r...

Background and Aims Electrocautery-tip lumen-apposing metal stents (EC-LAMSs) have extended the indications of therapeutic EUS. We aimed to retrospectively evaluate safety, technical and clinical success of a newly developed EC-LAMS for various EUS-guided procedures. Methods We included and retrospectively analyzed consecutive patients at 8 tertia...

Introduction: Endoscopic management of Zenker diverticuli (ZD) has traditionally been via septotomy technique. The recent development of tunneling technique has shown to be both efficacious and safe. The aim of this study is to evaluate the tunneling technique using per oral endoscopic myotomy (Z-POEM) versus septotomy. Methods: Patients who und...

Background Effective hemostasis is essential to prevent rebleeding. We evaluated the efficacy and feasibility of the Over-The-Scope Clip (OTSC) system compared to combined therapy (through-the-scope clips with epinephrine injection) as a first-line endoscopic treatment for high-risk bleeding peptic ulcers.Methods We retrospectively analyzed data of...

Background and study aims Endoscopic retrograde cholangiopancreatography (ERCP) is the gold standard procedure for malignant jaundice palliation; however, it can be challenging when a duodenal self-expandable metal stent (SEMS) is already in place. Patients and methods The primary aim of our study was to evaluate the technical feasibility of the pl...

Background and study aims The use of fluoroscopy during pregnancy should be minimized given that a clear-cut safe radiation dose in pregnancy is unknown. The role of digital single-operator cholangioscopy (D-SOC) as an alternative to standard enodoscopic retrograde cholangiopancreatography (ERCP) in pregnant patients has not been comprehensively st...

Background: Cyanoacrylate (CYA) injection can be performed using a standard upper endoscopy technique or under endoscopic ultrasound (EUS) guidance alone or in combination with coils. There is little information available on the economic impact of these treatment methods. Aim: To compare the cost-effectiveness of treating gastric varices by CYA...

An early and accurate diagnosis of biliary strictures yields optimal patient outcomes; however, endoscopic retrograde cholangiopancreatography (ERCP) with cytobrush/biopsy forceps has low sensitivity with a high number of false negatives. Various attempts to improve the accuracy of diagnosing indeterminate biliary strictures though ERCP-guided spec...

Background and study aims Assessment of endoscopic ultrasonography (EUS)-elastography of the liver and spleen may identify patients with portal hypertension secondary to chronic liver disease. We aimed to evaluate use of EUS-elastography of the liver and spleen in identification of portal hypertension in patients with chronic liver disease. Patient...

Aim: The aim of the study was to determine the usefulness of known biomarkers as pre-operative predictors of complicated acute appendicitis (CAA) and perforated appendicitis (PA). Materials and methods: This was an observational, analytic, cross-sectional, and prospective study at Hospital Teodoro Maldonado Carbo (August 2016-December 2017). Eva...

Background and Aims Various macroscopic features are proposed for the diagnosis of biliary lesions during digital single-operator cholangioscopy (DSOC); however, neovasculature may be one of the most reliable features of neoplasia. We aimed to evaluate the detection of neovasculature during DSOC to distinguish neoplastic from non-neoplastic bile du...

Background and study aims Digital, per-oral cholangioscopy (POCS) allows diagnosis of biliary ducts disorders and treatment for complicated stones. We aimed to determine the diagnostic accuracy of digital POCS systems for stricture lesions and the factors precluding complete biliary stone clearance. Patients and methods We performed a retrospective...

The case was an 82-year-old Hispanic female who complained of painless jaundice and weight loss. Endoscopic retrograde cholangiopancreatography (ERCP) showed a distal common bile duct (CBD) stricture with dilatation of the intra and extra-hepatic bile ducts.

Background: After appendectomy due to complicated acute appendicitis (CAA), there are some alternatives as antibiotic scheme: ciprofloxacin/metronidazole; as well as monoscheme based on carbapenems: ertapenem, meropenem, and imipenem. Aim: This study aims to prove the efficacy of carbapenems versus ciprofloxacin/metronidazole in CAA post-operati...

Background and aims Irritable bowel syndrome (IBS) is considered to be a functional disease, but recent data indicate measurable organic alterations. We aimed to determine the presence of colorectal mucosa microinflammation in vivo via probe-confocal laser endomicroscopy (pCLE) and histological evaluation in IBS patients. Methods This was a prospec...

Background Gastric variceal bleeding is a life-threating condition with challenging management. We aimed to compare the efficacy and safety of endoscopic ultrasonography (EUS)-guided coil embolization and cyanoacrylate injection versus EUS-guided coil embolization alone in the management of gastric varices. Methods A single-center, parallel-randomi...

Background: Accurate detection of gastric infection by Helicobacter pylori (H. pylori) and premalignant lesions are important for effective provision of treatment, preventing the development of gastric neoplasia. Optical enhancement systems with optical magnification improved the identification of mucosal superficial and vascular patterns in patie...

We read with great interest the scientific letter by Sánchez Melgarejo JF et al., in which they report a degenerate Todani Ia choledochal cyst in a patient with a pancreas divisum. However, patients with a choledochal cyst might benefit from per oral cholangioscopy for malignancy detection and extension evaluation.

Background The use of fully covered self-expandable metallic stents (FCSEMS) has opened the door to treat stenosis in the post-bariatric stomach. We hypothesized that endoscopically securing a FCSEMS would be technically feasible, effective, and safe for > 30-day dwell time. Objectives To assess the technical feasibility, clinical efficacy, and sa...

Gastroesophageal variceal bleeding is a life-threatening complication in patients with liver cirrhosis and portal hypertension. The endoscopic injection of cyanoacrylate is considered as the first-line alternative for gastric varices treatment; however, the incidence of adverse events supports the endoscopic ultrasound–guided approach. Endoscopic u...

Background and study aims Gastric variceal bleeding management is challenging, especially in the pediatric population. Endoscopic cyanoacrylate glue injection is considered the standard for management of gastric varices but it is associated with a high rebleeding rate. Endoscopic ultrasound (EUS)-guided placement of coils with cyanoacrylate is a ne...

Background and study aims The aim of this study was to evaluate the diagnostic yield of endoscopy using optical enhancement (OE system) with optical magnification to predict reflux in non-erosive reflux disease (NERD) patients. Patients and methods A prospective, non-randomized, single-blind study was performed from September 2015 to January 2016....

Background and Aims Transoral outlet reduction (TORe) by devitalization and/or endoscopic suturing (ES) has been implemented in the management of weight regain post-RYGB. This study aims to assess the efficacy and safety of TORe following an insurance-based algorithm. Methods A prospectively maintained database of patients who underwent TORe betwe...

Background: Bougies dilation is considered an effective technique for the treatment of simple benign esophageal strictures. The "rule of three" has been advocated to prevent reported adverse events such as bleeding and perforation. However, adherence to this rule has increased the cost and duration of treatment. Objective: To demonstrate the saf...

Goals: The goal of this study was to evaluate the safety and feasibility of routine segmental retroflexed withdrawal viewing (RV) of the colon with the RetroView colonoscope. Materials and methods: This was a prospective, single-center, 2-stage diagnostic trial. After cecal intubation, mucosal evaluation by forward viewing (FV) and RV was perfor...

Background/aims: Capsule endoscopy is a diagnostic method for evaluating the small bowel lumen and can detect undiagnosed lesions. The aim of this study was to evaluate the diagnostic yield and clinical impact of capsule endoscopy in patients with refractory diarrhea-predominant irritable bowel syndrome and functional abdominal pain. Methods: Th...

Dieulafoy’s lesions are vascular anomalies that produce gastrointestinal bleeding of the mucosa from an abnormally long and tortuous submucosal artery. It is found predominately in the stomach (80%) and less frequently in the duodenum. They constitute the 6% of all non-variceal bleeding and the 1 to 2% of all gastrointestinal bleeding source. We re...

Background: The aim of this study was to propose a novel, comprehensive, macroscopic classification for bile duct lesions. Methods: A two-stage protocol was designed. In Stage I, a retrospective study (September 2013 to September 2015) of patients with bile duct lesions detected by peroral cholangioscopy (POCS) was performed. A total of 315 imag...