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The role of endoscopy in gastroduodenal obstruction and gastroparesis

2011; Elsevier BV; Volume: 74; Issue: 1 Linguagem: Inglês

10.1016/j.gie.2010.12.003

1097-6779

Norio Fukami, Michelle A. Anderson, Karim Khan, M. Edwyn Harrison, Vasudhara Appalaneni, Tamir Ben‐Menachem, Georges Decker, Robert D. Fanelli, Laurel Fisher, Steven O. Ikenberry, Rajeev Jain, Terry L. Jue, Mary L. Krinsky, John T. Maple, Ravi Sharaf, Jason A. Dominitz,

Gastroesophageal reflux and treatments

This is one of a series of statements discussing the use of GI endoscopy in common clinical situations. The Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy (ASGE) prepared this text. In preparing this guideline, a search of the medical literature was performed by using PubMed. Additional references were obtained from the bibliographies of the identified articles and from recommendations of expert consultants. Guidelines for appropriate use of endoscopy are based on a critical review of the available data and expert consensus at the time the guidelines are drafted. Further controlled clinical studies may be needed to clarify aspects of this guideline. This guideline may be revised as necessary to account for changes in technology, new data, or other aspects of clinical practice. The recommendations are based on reviewed studies and are graded on the strength of the supporting evidence (Table 1).1Guyatt G.H. Oxman A.D. Vist G.E. et al.GRADE: an emerging consensus on rating quality of evidence and strength of recommendations.BMJ. 2008; 336: 924-926Crossref PubMed Google Scholar The strength of individual recommendations is based both on the aggregate evidence quality and an assessment of the anticipated benefits and harms. Weaker recommendations are indicated by phrases such as “We suggest…,” whereas stronger recommendations are typically stated as “We recommended…”Table 1GRADE System for rating the quality of evidence for guidelinesAdapted from Guyatt et al.1Guyatt G.H. Oxman A.D. Vist G.E. et al.GRADE: an emerging consensus on rating quality of evidence and strength of recommendations.BMJ. 2008; 336: 924-926Crossref PubMed Google ScholarQuality of evidenceDefinitionSymbolHigh qualityFurther research is very unlikely to change our confidence in the estimate of effect⊕⊕⊕⊕Moderate qualityFurther research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate⊕⊕⊕○Low qualityFurther research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate⊕⊕○○Very low qualityAny estimate of effect is very uncertain⊕○○○ Open table in a new tab This guideline is intended to be an educational device to provide information that may assist endoscopists in providing care to patients. This guideline is not a rule and should not be construed as establishing a legal standard of care or as encouraging, advocating, requiring, or discouraging any particular treatment. Clinical decisions in any particular case involve a complex analysis of the patient's condition and available courses of action. Therefore, clinical considerations may lead an endoscopist to take a course of action that varies from these guidelines. Enteral obstruction and delayed gastric emptying can result from a variety of benign and malignant conditions. Endoscopy is an important tool in the evaluation of these patients and can identify, localize, or exclude structural causes. Moreover, various endoscopic procedures may be used to treat the underlying etiology or alleviate symptoms. This document describes the role of endoscopy in known and suspected obstruction of the proximal GI tract. A discussion of special considerations in a pediatric population is also included. Gastric outlet obstruction (GOO) is caused by mechanical gastroduodenal obstruction or motility disorders and can be divided into 3 major categories: benign mechanical, malignant mechanical, and motility disorders (Table 2). Peptic ulcer disease with or without secondary stricture is the most common cause of benign mechanical GOO, although the recent decline in peptic ulcer disease has decreased the incidence of clinically evident peptic strictures.2Wang Y.R. Richter J.E. Dempsey D.T. Trends and outcomes of hospitalizations for peptic ulcer disease in the United States, 1993 to 2006.Ann Surg. 2010; 251: 51-58Crossref PubMed Scopus (173) Google Scholar Malignant mechanical GOO usually results from cancer affecting the distal stomach or proximal duodenum. Gastric and pancreatic cancers are the most common malignant mechanical causes of GOO.3Dormann A. Meisner S. Verin N. et al.Self-expanding metal stents for gastroduodenal malignancies: systematic review of their clinical effectiveness.Endoscopy. 2004; 36: 543-550Crossref PubMed Scopus (366) Google ScholarTable 2Differential diagnosis of gastric outlet obstructionMechanicalMotility disordersBenign Peptic ulcer diseaseGastroparesis Crohn's diseasePostsurgical gastroparesis NSAID-related strictureMedication-associated dysmotility Anastomotic strictureSystemic disease-associated (eg, scleroderma, amyloidosis) Postradiation strictureIntestinal pseudo-obstruction Foreign body or bezoarParaneoplastic syndrome Gallstone (Bouveret syndrome) Benign polyps (eg, antral polyps, inflammatory, hyperplastic, inflammatory pseudotumor, hamartoma, Peutz-Jeghers syndrome) Eosinophilic gastroenteritis Extrinsic compression (eg, annular pancreas, chronic pancreatitis with/without pseudocyst)Malignant Gastroduodenal cancer, gastric lymphoma (eg, MALT lymphoma), pancreatic cancer, cystic neoplasm of the pancreas, gallbladder and bile duct cancer, carcinoid, retroperitoneal lymphadenopathy (eg, metastatic tumor, lymphoma), retroperitoneal sarcoma, leiomyosarcoma, GI stromal tumorChildren Hypertrophic pyloric stenosis, duodenal or pyloric atresia, antral and duodenal webs, gastroduodenal duplication, gastroduodenal intussusception and gastric volvulus, heterotopic pancreatic tissue in the gastric antrum, diaphragmatic herniation, malrotation and peritoneal fibrous bands, congenital anomalies of the pancreatobiliary system, foreign body, peptic ulcer disease, eosinophilic GI disease, chronic granulomatous disease, Crohn's disease, lymphoproliferative diseaseMALT, Mucosa-associated lymphoid tissue; NSAID, nonsteroidal anti-inflammatory drug. Open table in a new tab MALT, Mucosa-associated lymphoid tissue; NSAID, nonsteroidal anti-inflammatory drug. The most common gastric motility disorder is gastroparesis, often resulting from long-standing diabetes, although gastroparesis may also be idiopathic, viral, or related to medications.4Abell T.L. Bernstein R.K. Cutts T. et al.Treatment of gastroparesis: a multidisciplinary clinical review.Neurogastroenterol Motil. 2006; 18: 263-283Crossref PubMed Scopus (300) Google Scholar, 5Parkman H.P. Hasler W.L. Fisher R.S. American Gastroenterological Association medical position statement: diagnosis and treatment of gastroparesis.Gastroenterology. 2004; 127: 1589-1591Abstract Full Text Full Text PDF PubMed Scopus (189) Google Scholar, 6Park M.I. Camilleri M. Gastroparesis: clinical update.Am J Gastroenterol. 2006; 101: 1129-1139Crossref PubMed Scopus (112) Google Scholar Surgical procedures that intentionally or unintentionally disrupt the vagus nerve (eg, procedures for peptic ulcer disease, bariatric procedures, esophagectomy, fundoplication) may also result in gastroparesis. Several solid and hematologic malignancies may induce gastroparesis and small-bowel dysmotility through a paraneoplastic process or secondary infiltrative diseases (eg, amyloidosis, carcinomatosis).7Lee H.R. Lennon V.A. Camilleri M. et al.Paraneoplastic gastrointestinal motor dysfunction: clinical and laboratory characteristics.Am J Gastroenterol. 2001; 96: 373-379Crossref PubMed Google Scholar, 8Tada S. Iida M. Yao T. et al.Intestinal pseudo-obstruction in patients with amyloidosis: clinicopathologic differences between chemical types of amyloid protein.Gut. 1993; 34: 1412-1417Crossref PubMed Scopus (108) Google Scholar Patients with GOO may present with nausea and vomiting, weight loss, abdominal bloating, early satiety, and/or abdominal discomfort. Because of shared clinical features, it is often difficult to distinguish motility disorders from mechanical obstruction or functional dyspepsia based solely on symptoms.9Soykan I. Sivri B. Sarosiek I. et al.Demography, clinical characteristics, psychological and abuse profiles, treatment, and long-term follow-up of patients with gastroparesis.Dig Dis Sci. 1998; 43: 2398-2404Crossref PubMed Scopus (496) Google Scholar, 10Parkman H.P. Schwartz S.S. Esophagitis and gastroduodenal disorders associated with diabetic gastroparesis.Arch Intern Med. 1987; 147: 1477-1480Crossref PubMed Scopus (72) Google Scholar Nevertheless, initial evaluation should include a detailed history and careful physical examination. Vomiting soon after a meal suggests an upper anatomic abnormality, whereas symptoms delayed for several hours after meals characterize gastroparesis or a more distal obstruction.11Helyer L. Easson A.M. Surgical approaches to malignant bowel obstruction.J Support Oncol. 2008; 6: 105-113PubMed Google Scholar Vomiting will frequently relieve symptoms from a proximal obstructive cause. GOO may not be clinically evident until high-grade obstruction occurs because of the ability of the stomach to distend significantly to accommodate contents. Patients with GOO may demonstrate a succussion splash on physical examination. Most patients with signs or symptoms of gastroduodenal obstruction or dysmotility will require structural evaluation with EGD and/or radiographic studies. If complete intestinal obstruction or perforation is suspected, initial evaluation with radiographic studies should be performed before endoscopy. CT is the preferred radiologic test for suspected intestinal obstruction.12Maglinte D.D. Howard T.J. Lillemoe K.D. et al.Small-bowel obstruction: state-of-the-art imaging and its role in clinical management.Clin Gastroenterol Hepatol. 2008; 6: 130-139Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar, 13Jaffer U. Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary Computed tomography for small bowel obstruction.Emerg Med J. 2007; 24: 790-791Crossref PubMed Scopus (1) Google Scholar, 14Desser T.S. Gross M. Multidetector row computed tomography of small bowel obstruction.Semin Ultrasound CT MR. 2008; 29: 308-321Crossref PubMed Scopus (29) Google Scholar Because oral barium contrast may interfere with subsequent endoscopy, its use should be minimized or avoided if endoscopy is anticipated. Furthermore, high osmolar water-soluble contrast agents can cause severe bronchial irritation and pulmonary edema when inadvertently aspirated in the setting of obstruction and thus should be used with extreme caution.15Morcos S.K. Review article: Effects of radiographic contrast media on the lung.Br J Radiol. 2003; 76: 290-295Crossref PubMed Scopus (50) Google Scholar Endoscopic examination after gastric decompression can usually identify the nature and the precise level of obstruction, but the degree of the stenosis often does not correlate with symptoms. Endoscopy also offers the capability of tissue sampling and endoscopic therapy, where indicated. When structural abnormalities have been excluded, GI motility can be evaluated by using scintigraphy, radiographic contrast techniques, breath testing, electrogastrography, or gastroduodenal manometry. A comprehensive technical review of the diagnosis of gastroparesis was published in 2004.16Parkman H.P. Hasler W.L. Fisher R.S. American Gastroenterological Association technical review on the diagnosis and treatment of gastroparesis.Gastroenterology. 2004; 127: 1592-1622Abstract Full Text Full Text PDF PubMed Scopus (588) Google Scholar Gastroduodenal manometry can be performed to differentiate intestinal myopathy from enteric or extrinsic neuropathy, but the availability of this test is limited and may not influence therapy.17Wiley J.W. Nostrant T.T. Owyang C. Evaluation of gastrointestinal motility: methodologic considerations.3rd ed, vol 2. Wiley-Blackwell, Malden (Mass)1999Google Scholar, 18Greydanus M.P. Camilleri M. Abnormal postcibal antral and small bowel motility due to neuropathy or myopathy in systemic sclerosis.Gastroenterology. 1989; 96: 110-115Abstract Full Text PDF PubMed Google Scholar, 19Camilleri M. Malagelada J.R. Abnormal intestinal motility in diabetics with the gastroparesis syndrome.Eur J Clin Invest. 1984; 14: 420-427Crossref PubMed Scopus (305) Google Scholar A wireless pH and motility capsule has been developed that can assist with assessing GI motility,20Cassilly D. Kantor S. Knight L.C. et al.Gastric emptying of a non-digestible solid: assessment with simultaneous SmartPill pH and pressure capsule, antroduodenal manometry, gastric emptying scintigraphy.Neurogastroenterol Motil. 2008; 20: 311-319Crossref PubMed Scopus (252) Google Scholar, 21Kloetzer L. Chey W.D. McCallum R.W. et al.Motility of the antroduodenum in healthy and gastroparetics characterized by wireless motility capsule.Neurogastroenterol Motil. 2010; 22 (e117): 527-533PubMed Google Scholar although its clinical utility remains to be defined.22Szarka L.A. Camilleri M. Methods for measurement of gastric motility.Am J Physiol Gastrointest Liver Physiol. 2009; 296: G461-G475Crossref PubMed Scopus (94) Google Scholar Treatment options for benign mechanical obstruction include balloon dilation, self-expandable metal stent (SEMS) placement, and surgery. GOO related to peptic ulcer disease can be treated with balloon dilation.23Solt J. Bajor J. Szabo M. et al.Long-term results of balloon catheter dilation for benign gastric outlet stenosis.Endoscopy. 2003; 35: 490-495Crossref PubMed Scopus (58) Google Scholar, 24DiSario J.A. Fennerty M.B. Tietze C.C. et al.Endoscopic balloon dilation for ulcer-induced gastric outlet obstruction.Am J Gastroenterol. 1994; 89: 868-871PubMed Google Scholar, 25Kozarek R.A. Botoman V.A. Patterson D.J. Long-term follow-up in patients who have undergone balloon dilation for gastric outlet obstruction.Gastrointest Endosc. 1990; 36: 558-561Abstract Full Text PDF PubMed Scopus (83) Google Scholar, 26Banerjee S. Cash B.D. Dominitz J.A. et al.The role of endoscopy in the management of patients with peptic ulcer disease.Gastrointest Endosc. 2010; 71: 663-668Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar Although technical success with immediate symptom improvement is common, multiple dilations are often required.23Solt J. Bajor J. Szabo M. et al.Long-term results of balloon catheter dilation for benign gastric outlet stenosis.Endoscopy. 2003; 35: 490-495Crossref PubMed Scopus (58) Google Scholar Perforation rates with balloon dilation in benign peptic strictures range from 3% to 7%, with higher rates corresponding to larger balloon diameter of more than 15 mm.23Solt J. Bajor J. Szabo M. et al.Long-term results of balloon catheter dilation for benign gastric outlet stenosis.Endoscopy. 2003; 35: 490-495Crossref PubMed Scopus (58) Google Scholar, 24DiSario J.A. Fennerty M.B. Tietze C.C. et al.Endoscopic balloon dilation for ulcer-induced gastric outlet obstruction.Am J Gastroenterol. 1994; 89: 868-871PubMed Google Scholar, 27Lam Y.H. Lau J.Y. Fung T.M. et al.Endoscopic balloon dilation for benign gastric outlet obstruction with or without Helicobacter pylori infection.Gastrointest Endosc. 2004; 60: 229-233Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar, 28Boylan J.J. Gradzka M.I. Long-term results of endoscopic balloon dilatation for gastric outlet obstruction.Dig Dis Sci. 1999; 44: 1883-1886Crossref PubMed Scopus (46) Google Scholar Balloon dilation can also be effective in the treatment of caustic-induced GOO or post-endoscopic submucosal dissection stricture at the pylorus.29Coda S. Oda I. Gotoda T. et al.Risk factors for cardiac and pyloric stenosis after endoscopic submucosal dissection, and efficacy of endoscopic balloon dilation treatment.Endoscopy. 2009; 41: 421-426Crossref PubMed Scopus (86) Google Scholar, 30Kochhar R. Dutta U. Sethy P.K. et al.Endoscopic balloon dilation in caustic-induced chronic gastric outlet obstruction.Gastrointest Endosc. 2009; 69: 800-805Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar Once adequate dilation is achieved, a durable response is seen in 70% to 80% of patients.23Solt J. Bajor J. Szabo M. et al.Long-term results of balloon catheter dilation for benign gastric outlet stenosis.Endoscopy. 2003; 35: 490-495Crossref PubMed Scopus (58) Google Scholar, 24DiSario J.A. Fennerty M.B. Tietze C.C. et al.Endoscopic balloon dilation for ulcer-induced gastric outlet obstruction.Am J Gastroenterol. 1994; 89: 868-871PubMed Google Scholar, 25Kozarek R.A. Botoman V.A. Patterson D.J. Long-term follow-up in patients who have undergone balloon dilation for gastric outlet obstruction.Gastrointest Endosc. 1990; 36: 558-561Abstract Full Text PDF PubMed Scopus (83) Google Scholar Treatment of Helicobacter pylori, when present, elimination of nonsteroidal anti-inflammatory drugs, and concurrent use of antisecretory therapy may improve sustained response.31Cherian P.T. Cherian S. Singh P. Long-term follow-up of patients with gastric outlet obstruction related to peptic ulcer disease treated with endoscopic balloon dilatation and drug therapy.Gastrointest Endosc. 2007; 66: 491-497Abstract Full Text Full Text PDF PubMed Scopus (67) Google Scholar The efficacy of proton pump inhibitor therapy may be attenuated in the setting of GOO because of a failure to reach the jejunum for absorption and premature activation in the acidic environment of stomach.31Cherian P.T. Cherian S. Singh P. Long-term follow-up of patients with gastric outlet obstruction related to peptic ulcer disease treated with endoscopic balloon dilatation and drug therapy.Gastrointest Endosc. 2007; 66: 491-497Abstract Full Text Full Text PDF PubMed Scopus (67) Google Scholar Recurrent stricture after endoscopic dilation may require surgical treatment. In one study, the need for more than 2 endoscopic dilations for symptoms was a significant predictor for the need for surgical treatment.32Perng C.L. Lin H.J. Lo W.C. et al.Characteristics of patients with benign gastric outlet obstruction requiring surgery after endoscopic balloon dilation.Am J Gastroenterol. 1996; 91: 987-990PubMed Google Scholar Although there have been case reports of SEMS placement for the treatment of benign stenosis of the pylorus, the experience with these devices in this patient population is very limited.26Banerjee S. Cash B.D. Dominitz J.A. et al.The role of endoscopy in the management of patients with peptic ulcer disease.Gastrointest Endosc. 2010; 71: 663-668Abstract Full Text Full Text PDF PubMed Scopus (92) Google Scholar, 33Dormann A.J. Deppe H. Wigginghaus B. Self-expanding metallic stents for continuous dilatation of benign stenoses in gastrointestinal tract—first results of long-term follow-up in interim stent application in pyloric and colonic obstructions.Z Gastroenterol. 2001; 39: 957-960Crossref PubMed Scopus (37) Google Scholar, 34Binkert C.A. Jost R. Steiner A. et al.Benign and malignant stenoses of the stomach and duodenum: treatment with self-expanding metallic endoprostheses.Radiology. 1996; 199: 335-338Crossref PubMed Scopus (131) Google Scholar Treatment options for malignant GOO include surgical resection, surgical bypass, endoscopic stenting, and palliative decompressive gastrostomy with or without feeding tube placement. Surgery is the preferred strategy for those patients who are potential candidates for curative resection. Diagnostic laparoscopy or exploratory laparotomy may be beneficial to assess the extent of disease with intent to perform surgical bypass as deemed necessary. Endoscopic placement of an SEMS should be considered provided there is no evidence of obstruction distal to the site of planned stent deployment. In patients with multiple sites of obstruction, palliative decompressive gastrostomy can be considered with jejunal feeding tube placement or total parenteral nutrition (TPN). SEMS are composed of metal alloys designed to be constrainable on a delivery catheter, yet resume their desired shape once the constraint is removed. Although some can be delivered through the endoscope, others have a larger delivery system that requires placement alongside the endoscope and/or with fluoroscopic guidance. Some SEMSs are covered by a membrane to help prevent tumor ingrowth. A detailed discussion of enteral stents is available in another ASGE document.35Tierney W. Chuttani R. Croffie J. et al.Enteral stents.Gastrointest Endosc. 2006; 63: 920-926Abstract Full Text Full Text PDF PubMed Scopus (56) Google Scholar Technical success is defined as the successful deployment of the stent at the desired anatomic location, whereas relief of obstructive symptoms and/or improvement of oral intake define clinical effectiveness. Attempts to place an SEMS may fail because of the inability to pass the guidewire beyond the level of the obstruction or other anatomic difficulties. Clinical improvement is commonly assessed by the Gastric Outlet Obstruction Score,36Adler D.G. Baron T.H. Endoscopic palliation of malignant gastric outlet obstruction using self-expanding metal stents: experience in 36 patients.Am J Gastroenterol. 2002; 97: 72-78Crossref PubMed Google Scholar quality of life, and performance status.37Schmidt C. Gerdes H. Hawkins W. et al.A prospective observational study examining quality of life in patients with malignant gastric outlet obstruction.Am J Surg. 2009; 198: 92-99Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar Case series of SEMS placement for gastroduodenal obstruction have found high technical and clinical success rates in patients with malignant GOO.3Dormann A. Meisner S. Verin N. et al.Self-expanding metal stents for gastroduodenal malignancies: systematic review of their clinical effectiveness.Endoscopy. 2004; 36: 543-550Crossref PubMed Scopus (366) Google Scholar, 38Graber I. Dumas R. Filoche B. et al.The efficacy and safety of duodenal stenting: a prospective multicenter study.Endoscopy. 2007; 39: 784-787Crossref PubMed Scopus (59) Google Scholar, 39Kim J.H. Song H.Y. Shin J.H. et al.Metallic stent placement in the palliative treatment of malignant gastroduodenal obstructions: prospective evaluation of results and factors influencing outcome in 213 patients.Gastrointest Endosc. 2007; 66: 256-264Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar, 40Maetani I. Isayama H. Mizumoto Y. Palliation in patients with malignant gastric outlet obstruction with a newly designed enteral stent: a multicenter study.Gastrointest Endosc. 2007; 66: 355-360Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar, 41Lowe A.S. Beckett C.G. Jowett S. et al.Self-expandable metal stent placement for the palliation of malignant gastroduodenal obstruction: experience in a large, single, UK centre.Clin Radiol. 2007; 62: 738-744Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar, 42van Hooft J.E. Uitdehaag M.J. Bruno M.J. et al.Efficacy and safety of the new WallFlex enteral stent in palliative treatment of malignant gastric outlet obstruction (DUOFLEX study): a prospective multicenter study.Gastrointest Endosc. 2009; 69: 1059-1066Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar, 43Piesman M. Kozarek R.A. Brandabur J.J. et al.Improved oral intake after palliative duodenal stenting for malignant obstruction: a prospective multicenter clinical trial.Am J Gastroenterol. 2009; 104: 2404-2411Crossref PubMed Scopus (96) Google Scholar, 44Havemann M.C. Adamsen S. Wojdemann M. Malignant gastric outlet obstruction managed by endoscopic stenting: a prospective single-centre study.Scand J Gastroenterol. 2009; 44: 248-251Crossref PubMed Scopus (29) Google Scholar, 45Kim C.G. Choi I.J. Lee J.Y. et al.Covered versus uncovered self-expandable metallic stents for palliation of malignant pyloric obstruction in gastric cancer patients: a randomized, prospective study.Gastrointest Endosc. 2010; 72: 25-32Abstract Full Text Full Text PDF PubMed Scopus (99) Google Scholar It is important to note that such studies are often composed of heterogeneous patient populations with various malignancies treated with an assortment of stents, making uniform conclusions about efficacy difficult. A systematic review of 32 case series summarized the technical success and clinical effectiveness of SEMSs.3Dormann A. Meisner S. Verin N. et al.Self-expanding metal stents for gastroduodenal malignancies: systematic review of their clinical effectiveness.Endoscopy. 2004; 36: 543-550Crossref PubMed Scopus (366) Google Scholar The mean survival time was 12 weeks (range 1-184 weeks). The technical success rate of endoscopic placement of SEMSs was 97%3Dormann A. Meisner S. Verin N. et al.Self-expanding metal stents for gastroduodenal malignancies: systematic review of their clinical effectiveness.Endoscopy. 2004; 36: 543-550Crossref PubMed Scopus (366) Google Scholar and ranged from 91% to 100% in prospective studies.38Graber I. Dumas R. Filoche B. et al.The efficacy and safety of duodenal stenting: a prospective multicenter study.Endoscopy. 2007; 39: 784-787Crossref PubMed Scopus (59) Google Scholar, 39Kim J.H. Song H.Y. Shin J.H. et al.Metallic stent placement in the palliative treatment of malignant gastroduodenal obstructions: prospective evaluation of results and factors influencing outcome in 213 patients.Gastrointest Endosc. 2007; 66: 256-264Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar, 40Maetani I. Isayama H. Mizumoto Y. Palliation in patients with malignant gastric outlet obstruction with a newly designed enteral stent: a multicenter study.Gastrointest Endosc. 2007; 66: 355-360Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar, 41Lowe A.S. Beckett C.G. Jowett S. et al.Self-expandable metal stent placement for the palliation of malignant gastroduodenal obstruction: experience in a large, single, UK centre.Clin Radiol. 2007; 62: 738-744Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar, 42van Hooft J.E. Uitdehaag M.J. Bruno M.J. et al.Efficacy and safety of the new WallFlex enteral stent in palliative treatment of malignant gastric outlet obstruction (DUOFLEX study): a prospective multicenter study.Gastrointest Endosc. 2009; 69: 1059-1066Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar, 43Piesman M. Kozarek R.A. Brandabur J.J. et al.Improved oral intake after palliative duodenal stenting for malignant obstruction: a prospective multicenter clinical trial.Am J Gastroenterol. 2009; 104: 2404-2411Crossref PubMed Scopus (96) Google Scholar, 44Havemann M.C. Adamsen S. Wojdemann M. Malignant gastric outlet obstruction managed by endoscopic stenting: a prospective single-centre study.Scand J Gastroenterol. 2009; 44: 248-251Crossref PubMed Scopus (29) Google Scholar, 45Kim C.G. Choi I.J. Lee J.Y. et al.Covered versus uncovered self-expandable metallic stents for palliation of malignant pyloric obstruction in gastric cancer patients: a randomized, prospective study.Gastrointest Endosc. 2010; 72: 25-32Abstract Full Text Full Text PDF PubMed Scopus (99) Google Scholar Clinical success was 89% overall, ranging from 63% to 95%.3Dormann A. Meisner S. Verin N. et al.Self-expanding metal stents for gastroduodenal malignancies: systematic review of their clinical effectiveness.Endoscopy. 2004; 36: 543-550Crossref PubMed Scopus (366) Google Scholar, 38Graber I. Dumas R. Filoche B. et al.The efficacy and safety of duodenal stenting: a prospective multicenter study.Endoscopy. 2007; 39: 784-787Crossref PubMed Scopus (59) Google Scholar, 39Kim J.H. Song H.Y. Shin J.H. et al.Metallic stent placement in the palliative treatment of malignant gastroduodenal obstructions: prospective evaluation of results and factors influencing outcome in 213 patients.Gastrointest Endosc. 2007; 66: 256-264Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar, 40Maetani I. Isayama H. Mizumoto Y. Palliation in patients with malignant gastric outlet obstruction with a newly designed enteral stent: a multicenter study.Gastrointest Endosc. 2007; 66: 355-360Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar, 41Lowe A.S. Beckett C.G. Jowett S. et al.Self-expandable metal stent placement for the palliation of malignant gastroduodenal obstruction: experience in a large, single, UK centre.Clin Radiol. 2007; 62: 738-744Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar, 42van Hooft J.E. Uitdehaag M.J. Bruno M.J. et al.Efficacy and safety of the new WallFlex enteral stent in palliative treatment of malignant gastric outlet obstruction (DUOFLEX study): a prospective multicenter study.Gastrointest Endosc. 2009; 69: 1059-1066Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar, 43Piesman M. Kozarek R.A. Brandabur J.J. et al.Improved oral intake after palliative duodenal stenting for malignant obstruction: a prospective multicenter clinical trial.Am J Gastroenterol. 2009; 104: 2404-2411Crossref PubMed Scopus (96) Google Scholar, 44Havemann M.C. Adamsen S. Wojdemann M. Malignant gastric outlet obstruction managed by endoscopic stenting: a prospective single-centre study.Scand J Gastroenterol. 2009; 44: 248-251Crossref PubMed Scopus (29) Google Scholar, 45Kim C.G. Choi I.J. Lee J.Y. et al.Covered versus uncovered self-expandable metallic stents for palliation of malignant pyloric obstruction in gastric cancer patients: a randomized, prospective study.Gastrointest Endosc. 2010; 72: 25-32Abstract Full Text Full Text PDF PubMed Scopus (99) Google Scholar Such discrepancies between technical success and clinical success are seen uniformly across prospective studies and may be attributed to underlying GI dysmotility with or without neural involvement by tumor, distal obstruction secondary to peritoneal carcinomatosis, or general deconditioning and anorexia caused by advanced malignancy.38Graber I. Dumas R