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Featured researches published by Yen I. Chen.


Clinical Gastroenterology and Hepatology | 2017

Similar Efficacies of Endoscopic Ultrasound Gallbladder Drainage With a Lumen-Apposing Metal Stent Versus Percutaneous Transhepatic Gallbladder Drainage for Acute Cholecystitis

Shayan Irani; Saowanee Ngamruengphong; Anthony Y. Teoh; Uwe Will; Jose Nieto; Barham K. Abu Dayyeh; S. Ian Gan; Michael C. Larsen; Hon Chi Yip; Mark Topazian; Michael J. Levy; Christopher C. Thompson; Andrew C. Storm; Gulara Hajiyeva; Amr Ismail; Yen I. Chen; Majidah Bukhari; Yamile Haito Chavez; Vivek Kumbhari; Mouen A. Khashab

Background & Aims Acute cholecystitis in patients who are not candidates for surgery is often managed with percutaneous transhepatic gallbladder drainage (PT‐GBD). Endoscopic ultrasound‐guided gallbladder drainage (EUS‐GBD) with a lumen‐apposing metal stent (LAMS) is an effective alternative to PT‐GBD. We compared the technical success of EUS‐GBD versus PT‐GBD, and patient outcomes, numbers of adverse events (AEs), length of hospital stay, pain scores, and repeat interventions. Methods We performed a retrospective study to compare EUS‐GBD versus PT‐GBD at 7 centers (5 in the United States, 1 in Europe, and 1 in Asia), from 2013 through 2015, in management of acute cholecystitis in patients who are not candidates for surgery. A total of 90 patients (56 men) with acute cholecystitis (61 calculous, 29 acalculous) underwent EUS‐GBD (n = 45) or PT‐GBD (n = 45). Data were collected on technical success, clinical success (resolution of symptoms or laboratory and/or radiologic abnormalities within 3 days of intervention), and need for repeat intervention. Characteristics were compared using Student t tests for continuous variables and the chi‐square test, or the Fisher exact test, when appropriate, for categorical variables. Adverse events were graded according to American Society for Gastrointestinal Endoscopy definitions and compared using the Fisher exact test. Postprocedure pain scores were compared using the Mann‐Whitney U test. Results Baseline characteristics, type, and clinical severity of cholecystitis were comparable between groups. In the EUS‐GBD group, noncautery LAMS were used in 30 patients and cautery‐enhanced LAMS were used in 15. Technical success was achieved for 98% of patients in the EUS‐GBD and 100% of the patients in the PT‐GBD group (P = .88). Clinical success was achieved by 96% of patients in the EUS‐GBD group and 91% in the PT‐GBD group (P = .20). There was a nonsignificant trend toward fewer AEs in the EUS‐GBD group (5 patients; 11%) than in the PT‐GBD group (14 patients; 32%) (P = .065). There were no significant differences in the severity of the AEs: mild, 2 in the EUS‐GBD group versus 5 in the PT‐GBD group (P = .27); moderate, 4 versus 3 (P = .98); severe, 1 versus 3 (P = .62); or deaths, 1 versus 3 (P = .61). The mean postprocedure pain score was lower in the EUS‐GBD group than in the PT‐GBD group (2.5 vs 6.5; P < .05). The EUS‐GBD group had a shorter average length of stay in the hospital (3 days) than the PT‐GBD group (9 days) (P < .05) and fewer repeat interventions (11 vs 112) (P < .05). The average number of repeat interventions per patients was 0.2 ± 0.4 EUS‐GBD group versus 2.5 ± 2.8 in the PT‐GBD group (P < .05). Median follow‐up after drainage was comparable in EUS‐GBD group (215 days; range, 1–621 days) versus the PT‐GBD group (265 days; range, 1–1638 days). Conclusions EUS‐GBD has similar technical and clinical success compared with PT‐GBD and should be considered an alternative for patients who are not candidates for surgery. Patients who undergo EUS‐GBD seem to have shorter hospital stays, lower pain scores, and fewer repeated interventions, with a trend toward fewer AEs. A prospective, comparative study is needed to confirm these results.


Clinical Gastroenterology and Hepatology | 2017

Efficacy and Safety of Peroral Endoscopic Myotomy for Treatment of Achalasia After Failed Heller Myotomy

Saowanee Ngamruengphong; Haruhiro Inoue; Michael B. Ujiki; Lava Y. Patel; Amol Bapaye; Pankaj N. Desai; Shivangi Dorwat; Jun Nakamura; Yoshitaka Hata; Valerio Balassone; Manabu Onimaru; Thierry Ponchon; Mathieu Pioche; Sabine Roman; Jérôme Rivory; François Mion; Aurélien Garros; Peter V. Draganov; Yaseen B. Perbtani; Ali Abbas; Davinderbir Pannu; Dennis Yang; Silvana Perretta; John Romanelli; David J. Desilets; Bu Hayee; Amyn Haji; Gulara Hajiyeva; Amr Ismail; Yen I. Chen

BACKGROUND & AIMS: In patients with persistent symptoms after Heller myotomy (HM), treatment options include repeat HM, pneumatic dilation, or peroral endoscopic myotomy (POEM). We evaluated the efficacy and safety of POEM in patients with achalasia with prior HM vs without prior HM. METHODS: We conducted a retrospective cohort study of 180 patients with achalasia who underwent POEM at 13 tertiary centers worldwide, from December 2009 through September 2015. Patients were divided into 2 groups: those with prior HM (HM group, exposure; n = 90) and those without prior HM (non‐HM group; n = 90). Clinical response was defined by a decrease in Eckardt scores to 3 or less. Adverse events were graded according to criteria set by the American Society for Gastrointestinal Endoscopy. Technical success, clinical success, and rates of adverse events were compared between groups. Patients were followed up for a median of 8.5 months. RESULTS: POEM was technically successful in 98% of patients in the HM group and in 100% of patients in the non‐HM group (P = .49). A significantly lower proportion of patients in the HM group had a clinical response to POEM (81%) than in the non‐HM group (94%; P = .01). There were no significant differences in rates of adverse events between the groups (8% in the HM group vs 13% in the non‐HM group; P = .23). Symptomatic reflux and reflux esophagitis after POEM were comparable between groups. CONCLUSIONS: POEM is safe and effective for patients with achalasia who were not treated successfully by prior HM. Although the rate of clinical success in patients with prior HM is lower than in those without prior HM, the safety profile of POEM is comparable between groups.


The American Journal of Gastroenterology | 2017

Comprehensive Analysis of Adverse Events Associated with per Oral Endoscopic Myotomy in 1826 Patients: An International Multicenter Study

Yamile Haito-Chavez; Haruhiro Inoue; Kristin W. Beard; Peter V. Draganov; Michael B. Ujiki; Burkhard H.A. Rahden; Pankaj N. Desai; Mathieu Pioche; Bu Hayee; Amyn Haji; Payal Saxena; Kevin M. Reavis; Manabu Onimaru; Valerio Balassone; Jun Nakamura; Yoshitaka Hata; Dennis Yang; Davinderbir Pannu; Ali Abbas; Yaseen B. Perbtani; Lava Y. Patel; J. Filser; Sabine Roman; Jérôme Rivory; François Mion; Thierry Ponchon; Silvana Perretta; Vivien W. Wong; Roberta Maselli; Saowanee Ngamruengphong

Objectives:The safety of peroral endoscopic myotomy (POEM) is still debated since comprehensive analysis of adverse events (AEs) associated with the procedure in large multicenter cohort studies has not been performed. To study (1) the prevalence of AEs and (2) factors associated with occurrence of AEs in patients undergoing POEM.Methods:Patients who underwent POEM at 12 tertiary-care centers between 2009 and 2015 were included in this case–control study. Cases were defined by the occurrence of any AE related to the POEM procedure. Control patients were selected for each AE case by matching for age, gender, and disease classification (achalasia type I and II vs. type III/spastic esophageal disorders).Results:A total of 1,826 patients underwent POEM. Overall, 156 AEs occurred in 137 patients (7.5%). A total of 51 (2.8%) inadvertent mucosotomies occurred. Mild, moderate, and severe AEs had a frequency of 116 (6.4%), 31 (1.7%), and 9 (0.5%), respectively. Multivariate analysis demonstrated that sigmoid-type esophagus (odds ratio (OR) 2.28, P=0.05), endoscopist experience <20 cases (OR 1.98, P=0.04), use of a triangular tip knife (OR 3.22, P=0.05), and use of an electrosurgical current different than spray coagulation (OR 3.09, P=0.02) were significantly associated with the occurrence of AEs.Conclusions:This large study comprehensively assessed the safety of POEM and highly suggests POEM as a relatively safe procedure when performed by experts at tertiary centers with an overall 7.5% prevalence of AEs. Severe AEs are rare. Sigmoid-type esophagus, endoscopist experience, type of knife, and current used can be considered as predictive factors of AE occurrence.


Endoscopy | 2017

Endoscopic ultrasound-guided creation of a transgastric fistula for the management of hepatobiliary disease in patients with Roux-en-Y gastric bypass

Saowanee Ngamruengphong; Jose Nieto; Rastislav Kunda; Vivek Kumbhari; Yen I. Chen; Majidah Bukhari; Mohamad H. El Zein; Renata Pieratti Bueno; Gulara Hajiyeva; Amr Ismail; Yamile Haito Chavez; Mouen A. Khashab

Background and aims Endoscopic retrograde cholangiopancreatography (ERCP) in patients who have undergone Roux-en-Y gastric bypass (RYGB) is technically challenging. We describe our multicenter experience using lumen-apposing metal stents (LAMSs) to create an endoscopic ultrasound-guided transgastric fistula (EUS-TG) to facilitate peroral ERCP in these patients. Patients and methods Thirteen patients with RYGB who underwent EUS-TG at three tertiary centers were included. EUS was used to guide puncture of the excluded stomach from the gastric pouch or jejunum; a LAMS was placed across the transgastric fistula. ERCP was performed via a duodenoscope passed through the LAMS. Results The technical success of EUS-TG was 100 % (13/13). ERCP through the LAMS was successful and clinical success was achieved in all patients. LAMS dislodgement during ERCP occurred in two patients and the stent was successfully repositioned without sequelae. After removal of the LAMS, the fistula was closed in 92 % of patients, either by endoscopic closure devices or argon plasma coagulation. None of the patients experienced procedure-related adverse events. Conclusion EUS-TG is an effective and safe method of accessing the excluded stomach and performing ERCP in patients with RYGB.


Current Opinion in Gastroenterology | 2016

Endoscopic approach to gastrointestinal bypass in malignant gastric outlet obstruction.

Yen I. Chen; Mouen A. Khashab

Purpose of review Malignant gastric outlet obstruction (GOO) is a debilitating complication of cancer associated with a poor prognosis. The primary aim in the management of malignant GOO is usually palliation starting with the reinstitution of luminal patency with either surgical bypass or enteral stenting. These traditional modalities, however, have important limitations. Endoscopic bypass is a novel approach to GOO and may be an ideal technique, in which a sustained bypass can be created through a minimally invasive approach. The goal of this review is to describe the technical aspects as well as the clinical data of endoscopic bypass. Recent findings A review of this novel technique is timely given recent developments of several accessories and techniques that allow for safer and easier endoscopic bypass including the advent of the lumen apposing stent, a specialized double-balloon enteric tube, the EUS-assisted technique, and the natural orifice transluminal surgery approach. In addition, accumulating and promising data have emerged supporting the endoscopic approach to gastric bypass. Summary Endoscopic bypass is a novel and developing field of therapeutic endoscopy with improving technique and promising clinical data. This review will help to shed light on the current status and future direction of this intricate endoscopic modality.


Gastrointestinal Endoscopy | 2017

Transoral incisionless endoscopic fundoplication guided by impedance planimetry to treat severe GERD symptoms after per-oral endoscopic myotomy

Yamile Haito Chavez; Saowanee Ngamruengphong; Majidah Bukhari; Yen I. Chen; Gerard Aguila; Mouen A. Khashab

A 61-year-old man with a history of type II achalasia and an Eckardt score of 6 underwent per-oral endoscopic myotomy (POEM). He presented 4 months after the procedure with GERD (score of 36 on GERD questionnaire) and an Eckardt score of 0. Upper endoscopy revealed LA grade C esophagitis, and a ph-Impedance study demonstrated a DeMeester score of 123.8. Transoral incisionless endoscopic fundoplication was then performed (Video 1). Preprocedure impedance planimetry was performed to obtain baseline measurements. A transoral staples device was advanced into the stomach through an overtube. Retroflexion facilitated the identification of the stapling location, and the


Clinical Gastroenterology and Hepatology | 2017

Efficacy and Safety of Digital Single-Operator Cholangioscopy for Difficult Biliary Stones

Olaya I. Brewer Gutierrez; Noor Bekkali; Isaac Raijman; Richard Sturgess; Divyesh V. Sejpal; Hanaa Dakour Aridi; Stuart Sherman; Raj J. Shah; Richard S. Kwon; James Buxbaum; C. Zulli; Wahid Wassef; Douglas G. Adler; Vladimir M. Kushnir; Andrew Y. Wang; Kumar Krishnan; Vivek Kaul; Demetrios Tzimas; Christopher J. DiMaio; Sammy Ho; Bret T. Petersen; Jong Ho Moon; B. Joseph Elmunzer; George Webster; Yen I. Chen; Laura K. Dwyer; Summant Inamdar; Vanessa Patrick; Augustin Attwell; Amy Hosmer

BACKGROUND & AIMS: It is not clear whether digital single‐operator cholangioscopy (D‐SOC) with electrohydraulic and laser lithotripsy is effective in removal of difficult biliary stones. We investigated the safety and efficacy of D‐SOC with electrohydraulic and laser lithotripsy in an international, multicenter study of patients with difficult biliary stones. METHODS: We performed a retrospective analysis of 407 patients (60.4% female; mean age, 64.2 years) who underwent D‐SOC for difficult biliary stones at 22 tertiary centers in the United States, United Kingdom, or Korea from February 2015 through December 2016; 306 patients underwent electrohydraulic lithotripsy and 101 (24.8%) underwent laser lithotripsy. Univariate and multivariable analyses were performed to identify factors associated with technical failure and the need for more than 1 D‐SOC electrohydraulic or laser lithotripsy session to clear the bile duct. RESULTS: The mean procedure time was longer in the electrohydraulic lithotripsy group (73.9 minutes) than in the laser lithotripsy group (49.9 minutes; P < .001). Ducts were completely cleared (technical success) in 97.3% of patients (96.7% of patients with electrohydraulic lithotripsy vs 99% patients with laser lithotripsy; P = .31). Ducts were cleared in a single session in 77.4% of patients (74.5% by electrohydraulic lithotripsy and 86.1% by laser lithotripsy; P = .20). Electrohydraulic or laser lithotripsy failed in 11 patients (2.7%); 8 patients were treated by surgery. Adverse events occurred in 3.7% patients and the stone was incompletely removed from 6.6% of patients. On multivariable analysis, difficult anatomy or cannulation (duodenal diverticula or altered anatomy) correlated with technical failure (odds ratio, 5.18; 95% confidence interval, 1.26–21.2; P = .02). Procedure time increased odds of more than 1 session of D‐SOC electrohydraulic or laser lithotripsy (odds ratio, 1.02; 95% confidence interval, 1.01–1.03; P < .001). CONCLUSIONS: In a multicenter, international, retrospective analysis, we found D‐SOC with electrohydraulic or laser lithotripsy to be effective and safe in more than 95% of patients with difficult biliary stones. Fewer than 5% of patients require additional treatment with surgery and/or extracorporeal shockwave lithotripsy to clear the duct.


Endoscopy | 2017

Submucosal tunneling endoscopic resection of a gigantic esophageal leiomyoma

Saowanee Ngamruengphong; Yuri Hanada; Olaya I. Brewer Gutierrez; Majidah Bukhari; Yen I. Chen; Vivek Kumbhari; Mouen A. Khashab

Submucosal tunneling endoscopic resection (STER) for removal of small upper gastrointestinal tumors arising from the muscularis propria has been demonstrated to be effective and safe [1, 2]. We demonstrated the submucosal tunneling technique for removal of a 10-cm esophageal leiomyoma, and subsequent management of a large mucosotomy. A 66-year-old woman presented with slowly progressive solid-food dysphagia. Computed tomography (CT) scan revealed a 10×4×3-cm esophageal mass. Esophagogastroduodenoscopy showed a large esophageal subepithelial lesion at 20–30 cm from the incisors. Endoscopic ultrasound (EUS) revealed a homogeneous hypoechoic lesion with central calcification arising from the muscularis propria. The results of EUS-guided fineneedle aspiration were consistent with leiomyoma. The patients refused surgical resection, and the submucosal tunneling endoscopic resection procedure was offered. Mucosal incision was done 3 cm proximal to the lesion using a triangular-tip knife (Olympus, Tokyo, Japan) (▶Fig. 1 a, b) (▶Video1). Submucosal fiber was dissected to create the submucosal tunnel and this was continued to the level of the lesion (▶Fig. 1 c). The lesion was dissected away from submucosal fiber, mucosa, and muscularis propria using an insulation-tipped diathermic knife (IT2 knife; Olympus) (▶Fig. 1d). Because of the size mismatch between the submucosal tunnel and the lesion, the lesion could not be removed from the tunnel. The decision was made to fragment the tumor into smaller pieces which were then removed from the tunnel (▶Fig. 1 e). A large defect was seen in the muscle layer after resection of the tumor (▶Fig. 1 f). We successfully placed 8 endoscopic clips (Resolution Clip; Boston Scientific, Boston, Massachusetts, USA) for closure of the mucosal incision. The patient was given Unasyn (ampicillin/sulbactam) intravenously. On postoperative day 1, esophagography revealed an esophageal leak. Urgent EGD showed that endoclips had fallen off (▶Fig. 1g). The clips were removed and a fully covered metal stent, 23mm in diameter (Wallflex; Boston Scientific), was deployed across the mucosal defect (▶Fig. 1h). The patient tolerated a soft diet and was discharged home on postoperative day 6. Repeat EGD was done at 4 weeks, with removal of the stent; the mucosal defect was well healed (▶Fig. 1 i). The patient had resolution of dysphagia.


Endoscopy | 2018

Endoscopic ultrasound-guided entero-enterostomy for the treatment of afferent loop syndrome: a multicenter experience

Olaya I. Brewer Gutierrez; Shayan Irani; Saowanee Ngamruengphong; Hanaa Dakour Aridi; Rastislav Kunda; Ali Siddiqui; Markus Dollhopf; Jose Nieto; Yen I. Chen; Nadav Sahar; Majidah Bukhari; Omid Sanaei; Marcia I. Canto; Vikesh K. Singh; Richard A. Kozarek; Mouen A. Khashab

BACKGROUND Afferent loop syndrome (ALS) is traditionally managed surgically and, more recently, endoscopically. The role of endoscopic ultrasound-guided entero-enterostomy (EUS-EE) has not been well described. The aim of this study was to assess the technical and clinical success and safety of EUS-EE. METHODS This was a multicenter, retrospective series at six centers in patients with ALS treated by EUS-EE. Data on patients treated with enteroscopy-assisted luminal stenting (EALS) at a single center were also collected. RESULTS 18 patients (mean age 64.2 years, 72 % post-pancreaticoduodenectomy, 10 female) underwent EUS-EE. The most common symptoms were vomiting (27.8 %) and jaundice (33.3 %). Clinical success included resolution of symptoms in 88.9 % and improvement to allow hospital discharge in 11.1 %. Technical success was achieved in 100 % of cases, with a mean procedure time of 29.7 minutes. The most common procedure was a gastro-jejunostomy (72.2 %). Three adverse events (16.7 %) occurred (two mild, one moderate). When compared with data on EALS, patients treated with EUS-EE needed fewer re-interventions (16.6 % vs. 76.5 %; P < 0.001). CONCLUSION EUS-EE seems to be safe and effective in the treatment of ALS. Indirect comparison with EALS suggested that EUS-EE is associated with a reduced need for re-intervention.


VideoGIE | 2017

EUS-guided arterial embolization with cyanoacrylate glue of a pancreatic neuroendocrine tumor infiltrating the gastric wall causing upper GI bleeding

Olaya I. Brewer Gutierrez; Robert Moran; Majidah Bukhari; Yen I. Chen; Mouen A. Khashab

re 1. A, First endoscopy showing the gastric cavity with rests of old blood and blood clots that precluded adequate visualization. No active bleeding . B, Second endoscopy showing the posterior wall of the gastric body with a large 4to 5-cm ulcer with heaped borders and extension into the deep e. No active bleeding or visible vessels were noted. C, MRI view showing a poorly defined hyperenhancing mass in the pancreatic tail, which abuts the er curvature of the stomach and the anterior aspect of the spleen, and multiple centrally necrotic hyperenhancing hepatic masses compatible with static disease. D, EUS view showing a hypoechoic, ill-defined, >3 cm mass in the pancreatic tail infiltrating the gastric wall. E, EUS view showing a feeding vessel at the inferior edge of the mass. F, EUS showing a 22G FNA needle targeting the feeding vessel during embolization. MRI, magnetic ance imaging.

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Vivek Kumbhari

Johns Hopkins University

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Amr Ismail

Johns Hopkins University

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Sindhu Barola

Johns Hopkins University

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