endoscopic retrograde cholangiopancreatography ( ercp ) and endoscopic ultrasound ( eus ) are increasingly utilized in the field of gastroenterology to diagnose and treat various upper gastrointestinal diseases .
more than 500,000 ercps are performed annually in the united states for pancreaticobiliary disorders and the role of eus has continued to expand over the past three decades to include a wide range of diagnostic and therapeutic interventions 1 
 2 .
non - forward - viewing ercp duodenoscopes and eus linear echoendoscopes are utilized in the upper gastrointestinal tract to perform various diagnostic and therapeutic maneuvers .
their endoscopic fields of view limit visualization of the lumen compared to the standard upper endoscope because these endoscopes are not designed to diagnose upper gastrointestinal tract lesions .
duodenoscopes and linear echoendoscopes are side - viewing and oblique - viewing endoscopes , respectively , with a field of view of 100 degrees , as compared to the 140-degree field of view of the standard gastroscope (  table1 ) .
in addition , these non - forward - viewing endoscopes have a larger diameter and more rigid distal tip , limiting their maneuverability and angulation range .
while these scopes are used for specific indications , the examination of the upper gastrointestinal tract is limited and luminal lesions may be missed .
a recent study evaluating the utility of standard upper endoscopy before eus demonstrated that clinically meaningful lesions were found on esophagogastroduodenoscopy ( egd ) in 22  % of patients 3 .
this study shows that a substantial amount of patients undergoing eus have significant incidental luminal lesions .
however , this study did not assess whether non - forward - viewing echoendoscopes would have missed meaningful lesions without the use of a gastroscope .  
eus , endoscopic ultrasound ; ercp , endoscopic retrograde cholangiopancreatography although an increasing number of ercp and eus procedures are being performed , there is currently no consensus on the use of a standard gastroscope in tandem with these procedures .
thus , the prevalence of missed luminal lesions when only using a non - forward - viewing endoscope is unclear .
the purpose of the current study was to examine the prevalence of clinically significant incidental upper gastrointestinal tract lesions that were found using a standard forward - viewing gastroscope following an ercp or eus exam using a duodenoscope or linear echoendoscope .
we hypothesized prior to analyzing the data that linear eus and ercp would miss significant esophageal gastrointestinal lesions but not gastric or duodenal lesions .
this was hypothesized because very little esophageal mucosa is seen while traversing the esophagus with a linear echoendoscope or duodenoscope .
this is a retrospective analysis of a single therapeutic endoscopist s procedures from 10/1/2013 to 6/1/2014 at a tertiary care medical center .
after two missed gastric adenocarcinomas were presented at the hospital tumor board in patients who had previously undergone ercps by another gastroenterologist , the institution adopted as standard of care routine egd at the time of all ercp or eus examinations .
the endoscopist chose to perform the ercp or eus first before the egd because his previous standard of care was to perform linear eus or ercp without a formal egd if the patient had no upper gastrointestinal tract symptoms and , in the event that patient tolerability of the procedure was not ideal and early termination of the procedure was required , the maximum time would be allotted to the main eus or ercp procedure .  
patients were included in this study if they : 1 ) underwent ercp and/or eus using a duodenoscope ( tjf - q180v , olympus america , center valley , pa , usa ) or a curved linear echoendoscope ( gf - uct180 , olympus america , center valley , pa , usa ) followed by an egd using a standard forward - viewing gastroscope ( hq190 , olympus america , center valley , pa , usa ) during a single procedure ; and 2 ) did not have dysphagia or other upper gastrointestinal tract symptoms .
all patients signed informed consent for ercp and/or eus and egd prior to the procedure .
patients were excluded from this analysis if : 1 ) they required an egd for diagnostic purposes ; 2 ) they had dysphagia ; 3 ) there was a clinical suspicion of upper gastrointestinal tract lesions ; 4 ) eus was performed using a radial echoendoscope ; 5 ) eus exam was not a pancreaticobiliary exam ; and 6 ) they had altered pancreaticobiliary anatomy .
all endoscopy reports recorded endoscopic lesions detected in the upper gastrointestinal tract . the data collected included age , gender , ethnicity , exam type , and indication for exam .
the oblique - viewing linear echoendoscope and side - viewing duodenoscope were passed in the usual fashion for the relevant eus and ercp exams .
upper gastrointestinal luminal findings visualized during passage of the scopes were recorded separately for each procedure .
the primary outcome of the study was to determine the proportion of clinically significant missed incidental lesions when using a side- or oblique - viewing endoscope as compared to the standard forward - viewing endoscope .
significant additional lesions found with a forward - viewing gastroscope were defined as findings that led to a change in the patient s medication regimen , additional endoscopic surveillance or interventions , or the need for other imaging studies .
gastric erythema , helicobacter pylori - negative gastritis , hiatal hernias or other anatomic abnormalities that did not affect management were not considered significant findings .
differences between groups were determined by using the student s t test or wilcoxon test for continuous variables and the fisher exact test for categorical variables .
the retrospective study was approved by the hofstra north shore long island jewish school of medicine institutional review board .
a total of 168 patients were identified who underwent ercp and/or eus using a side- or oblique - viewing endoscope followed by an egd using a forward - viewing gastroscope during a single procedure .
sixty - eight men ( 40  % ) and 100 women ( 60  % ) were identified .
the median patient age was 55 years ( range : 19    92 ) .
the most common indications for the initial procedure were known or suspected choledocholithiasis , pancreatic mass , chronic pancreatitis , or evaluation of dilated pancreatic or bile ducts .  
cbd , common bile duct ; ruq , right upper quadrant ; pd , pancreatic duct ; fap , familial adenomatous polyposis . of the 168 patients ,
52 procedures were done with a duodenoscope followed by a gastroscope , 83 procedures were done with a curved linear echoendoscope followed by a gastroscope , and 33 patients were done using both a linear echoendoscope and a duodenoscope followed by a gastroscope . of the latter patients , 14 ( 8  % ) had significant incidental clinical lesions found using a non - forward - viewing endoscope , including gastric / duodenal ulcers , h. pylori gastritis , duodenal polyp , and an ampullary adenoma , all of which were not included in the calculations for lesions missed by non - forward - viewing endoscopes .
clinically significant additional lesions diagnosed with a gastroscope but missed by a non - forward - viewing endoscope were found in 30/168 patients ( 18  % ) .
egd with a gastroscope after a linear eus resulted in additional lesion findings in 17/83 patients ( 20.5  % ,   =  13.385 , p  =  0.00025 ) .
egd with a gastroscope after an ercp with a duodenoscope resulted in additional lesions findings in 10  /52 patients ( 19.2  % ,   =  9.987 , p  =  0.00157 ) .
egd with a gastroscope after the use of both a linear echoendoscope and a duodenoscope resulted in additional lesions findings in 3/33 patients ( 9  % ,   =  3.219 , p  =  0.07 ) .
hgd , high - grade dysplasia both medication and procedural changes additional lesions diagnosed with a forward - viewing gastroscope and missed with a side - viewing duodenoscope included barrett s esophagus ( 2 ) , esophageal candidiasis ( 1 ) , esophageal varices ( 1 ) , reflux esophagitis ( 1 ) , focal h. pylori - positive gastritis ( 2 ) , and gastric ulcers in the antrum ( 2 ) and fundus ( 1 ) .
additional lesions missed with an oblique - viewing linear echoendoscope included barrett s esophagus ( 2 ) , esophageal candidiasis ( 1 ) , esophageal varices ( 2 ) , reflux esophagitis ( 1 ) , esophageal ulcer ( 1 ) , focal h. pylori gastritis ( 5 ) , gastric ulcer in the antrum ( 1 ) , gastric adenoma with high - grade dysplasia in the fundus ( 1 ) , duodenal angioectasia ( second part ) ( 1 ) , and adenomatous duodenal polyps ( second part ) ( 2 ) .
focal h. pylori gastritis was seen as focal erythema that histology from biopsies showed h. pylori .
finally , lesions missed by both non - forward - viewing endoscopes in a single procedure included barrett s esophagus ( 2 ) and esophageal varices ( 1 ) ( table  3 ) .
two lesions , a duodenal polyp and an ampullary adenoma , were visualized with a side - viewing duodenoscope and not seen with the standard gastroscope .
no adverse events were reported in any of the patients undergoing standard egd following a eus or ercp .
while these endoscopes are required to traverse the upper gastrointestinal tract to obtain their images , it is unclear if the endoscopist should be performing a detailed exam of the upper gastrointestinal tract during the same procedure .
our study helps answer this question as the literature to our knowledge is surprisingly sparse on this topic . in our study we found that significant incidental upper gastrointestinal lesions is found when a formal exam is performed with a gastroscope .  
a recent study of 204 patients found that 22  % were found to have clinically meaningful lesions on egd prior to eus for pancreaticobiliary indications and the authors of the study supported performing an egd for any patient undergoing eus 3 .
however , in the study , an egd was performed before the eus exam , and therefore it is not known if the clinically meaningful lesions would have been detected by an oblique - viewing echoendoscope without performing an egd . in our study
, an egd was performed after a linear eus exam and resulted in additional lesions findings in 17/83 patients ( 20.5  % ) .
furthermore , no studies have evaluated the role of an egd in detecting clinically meaningful lesions when performed either before or after an ercp . in our study ,
an egd with a gastroscope after an ercp with a duodenoscope resulted in additional lesions findings in 10/52 patients ( 19.2  % ) . a previous study of 172 patients compared egd and endoscopic ultrasound with radial eus for the evaluation of upper abdominal pain and demonstrated combined luminal findings in 25  % of the patients 4 .
patients were randomized to undergo luminal examination with both a standard gastroscope and an oblique - viewing radial echoendoscope by separate gastroenterologists in tandem prior to sonographic examination . in the subset analysis
, there were no overall differences between the two scopes for detecting mucosal lesions , but the radial echoendoscope missed several barrett s esophagus , gastric ulcers , and submucosal lesions .
the ability to take biopsies with the radial scope was also limited , requiring a 56  % conversion rate to a standard endoscope . however ,
this study cohort only included patients who were referred to gastroenterologists for diagnostic egds to evaluate their upper abdominal pain , therefore , the findings can not be extrapolated to asymptomatic patients and patients referred for eus for other indications .
another study of 200 patients with dyspepsia demonstrated that oblique - viewing radial eus had sensitivity and specificity of 80  % and 95  % , respectively , for detecting luminal lesions when compared to egd 5 . in this study , patients who were referred for dyspepsia underwent radial eus followed by egd to look for both luminal and extraluminal etiologies of their symptoms .
luminal lesions that were missed by eus included duodenal ulcers and reflux esophagitis . given that the primary goal of this study was to evaluate an eus - based management strategy for dyspepsia , only findings that accounted for dyspeptic symptoms were reported .
this study cohort included only patients with dyspepsia . because clinically significant lesions do not always cause symptoms , these findings do not translate to our study population who were undergoing eus for both symptomatic and asymptomatic indications .
our study evaluated patients referred for ercp and/or eus .  although it is not known how many patients had undergone previous upper endoscopic evaluation prior to the procedures analyzed , our findings demonstrate the importance of performing an egd during ercp and/or eus . 
our results among 168 patients showed that egd with a forward - viewing gastroscope yielded additional meaningful findings in 19  % ( 10  /52 ) of patients following an ercp with a duodenoscope , 20  % ( 17/83 ) of patients following a linear eus , and 9  % ( 3/33 ) of patients utilizing both a duodenoscope and a linear echoendoscope .
our findings coincide with previous published rates of incidental lesions requiring management changes found during egd performed for various reasons , which range from 22  % to 62  % , but it is the first to show the high miss rate of significant lesions with both duodenoscopes and linear eus echoendoscopes 3 
 6 
 7 .
prior to data analysis , we hypothesized that nearly all of the missed lesions during non - forward - viewing endoscopy would be esophageal given the semi-blind  passage of the scope through the narrowed tubular lumen of the esophagus compared to the stomach and duodenum .
however , 15/30 of the missed lesions ( 50  % ) were found in the stomach and duodenum , suggesting that luminal diameter was not the main factor contributing to missed lesions .  
additional lesions diagnosed by egd requiring endoscopic treatment included argon plasma coagulation ( apc ) of an angioectasia , endoscopic mucosal resection of a gastric adenoma with high - grade dysplasia , and variceal band ligation .
additional lesions requiring further endoscopic surveillance included barrett s esophagus , esophageal varices , and gastric ulcers .
additional significant medical interventions included treatment for h. pylori , esophageal varices , and cirrhosis workup and management .
one patient with a pancreatic head cyst causing partial duodenal obstruction diagnosed on forward - viewing endoscopy was admitted to the hospital for management of her symptoms .   in this study
, we performed the egd after the indicated ercp or eus procedure to maximize time for the main procedure in the event that the procedure had to be terminated prematurely .
previous data have suggested that performing standard upper endoscopy prior to eus may detect luminal lesions that will affect subsequent eus in 9.8  % to 12  % of patients , thus preventing potential complications during eus 3 
 8 .
however , other studies have shown eus to be a safe procedure with a low complication rate even if performed without a prior egd 9 . in our study ,
zero adverse events / complications were experienced during non - forward - viewing exams . it should be noted that these patients had no upper gastrointestinal symptoms .
patients with upper gastrointestinal symptoms underwent egd first and were not included in this study .  
this study strongly supports the notion that standard forward - viewing endoscopy should be performed at the same session of pancreaticobiliary eus and ercp .
this study did not evaluate the increased cost of performing a standard egd . the previously described study on this topic did not evaluate cost effectiveness either 3 .
the additional costs would be significant as there are costs associated with cleaning the additional gastroscope , equipment to biopsy ( e.  g. , biopsy forceps ) , provide additional therapy ( e.  g. , apc of lesions ) , physician fee for the additional procedure , etc .
however , the additional lesions discovered in this cohort were significant and would likely be clinically significant in the future , adding to the cost of future gastrointestinal healthcare ( e.  g. , cost of gastrointestinal bleeding in incidentally found vascular ectasias or varices , gastric cancer in the incidental gastric adenoma with high - grade dysplasia , duodenal cancer in the incidental duodenal adenoma , etc ) .
it is also possible that some of the incidentally found lesions increased healthcare costs without clinical benefit ( e.  g. , enrolling patients with incidentally found non - dysplastic barrett s esophagus that will not progress to neoplasia in a surveillance program , eradication of h. pylori that never would have caused significant disease , etc . ) .
future studies are needed to investigate the cost effectiveness of forward - viewing endoscopy at the time of pancreaticobiliary eus and ercp .  
this study also shows that in patients without upper gastrointestinal symptoms who undergo pancreaticobiliary eus or ercp , the order of forward - viewing endoscopic exam is irrelevant .
there were no complications associated with the forward - viewing endoscopy when performed after eus or ercp .
there is a theoretical risk that an oblique or side - viewing scope which traverses an unknown esophageal or duodenal stricture / lesion could possibly lead to a perforation . for this theoretical risk only , we would recommend that the forward - viewing endoscopy be performed before every pancreaticobiliary eus and ercp .  
this study has certain limitations which should be noted , including the limitations inherent in its retrospective design .
however , all endoscopic findings for each exam were recorded separately on the procedure report , thus the groups were not difficult to compare .
other practicing therapeutic endoscopists at our institution were not included in the study because their standard of care was to perform an egd prior to the eus or ercp .
in addition , an inherent limitation for which we can not account is the theoretical subconscious decreased effort of the endoscopist to look for incidental upper gastrointestinal tract lesions knowing that a forward - viewing endoscopy is going to be performed .
however , a significant number of lesions were discovered on eus and ercp before forward - viewing endoscopy , which makes this less likely . in summary
, the current study demonstrates that non - forward - viewing duodenoscopes and linear echoendoscopes miss a significant number of meaningful incidental upper gastrointestinal luminal lesions .
performing an upper endoscopy with a forward - viewing gastroscope at the time of ercp or eus leads to an increased yield of meaningful incidental upper gastrointestinal lesions .
gastroenterologists who perform linear eus or ercp should strongly consider performing a formal egd with a gastroscope at the time of the eus or ercp exam .
 
 background and study aims : it is unknown whether significant incidental upper gastrointestinal lesions are missed when using non - forward - viewing endoscopes without completing a forward - viewing exam in linear endoscopic ultrasound ( eus ) or endoscopic retrograde cholangiopancreatography ( ercp ) exams . 
 we evaluated whether significant upper gi lesions are missed during eus and ercp when upper endoscopy is not performed routinely with a gastroscope . 
 
 patients and methods : a retrospective analysis was performed in which an egd with a forward - viewing gastroscope was performed after using a non - forward - viewing endoscope ( linear echoendoscope , duodenoscope , or both ) during a single procedure . 
 upper gastrointestinal tract findings were recorded separately for each procedure . 
 significant lesions found with a forward - viewing gastroscope were defined as findings that led to a change in the patient s medication regimen , additional endoscopic surveillance / interventions , or the need for other imaging studies . 
 
 results : a total of 168 patients were evaluated . in 83 patients , 
 a linear echoendoscope was used , in 52 patients a duodenoscope was used , and in 33 patients both devices were used . 
 clinically significant additional lesions diagnosed with a gastroscope but missed by a non - forward - viewing endoscope were found in 30  /168 patients ( 18  % ) . 
 egd after linear eus resulted in additional lesion findings in 17  /83 patients ( 20.5  % , 2  =  13.385 , p  =  0.00025 ) . 
 egd after use of a duodenoscope resulted in additional lesions findings in 10  /52 patients ( 19.2  % , 2  =  9.987 , p  =  0.00157 ) . 
 egd after the use of both a linear echoendoscope and a duodenoscope resulted in additional lesions findings in 3/33 patients ( 9  % , 2  =  3.219 , p  =  0.07 ) . 
 
 conclusion : non forward - viewing endoscopes miss a significant amount of incidental upper gastrointestinal lesions during pancreaticobiliary endoscopy . performing an egd with a gastroscope at the time of linear eus or ercp 
 can lead to increased yield of upper gastrointestinal lesions . 
Introduction
Patients and methods
Results
Discussion