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Gastroesophageal acid reflux mainly occurs on the right side of the esophagus

      To the Editor:
      We read with great interest the study by Cassani et al
      • Cassani L.
      • Sumner E.
      • Slaughter J.C.
      • et al.
      Directional distribution of neoplasia in Barrett's esophagus is not influenced by distance from the gastroesophageal junction.
      describing the asymmetric circumferential distribution of Barrett's neoplasms. The results of their study suggest the importance of endoscopic examination of the right side wall of the esophagus, not only in patients with short-segment Barrett's esophagus (SSBE) but also those with long-segment Barrett's esophagus (LSBE), for detecting early-stage adenocarcinomas.
      Our group is also interested in the asymmetrical circumferential distribution of various esophagogastric lesions, and we first published a study in 2006 that investigated the prevalence of esophageal mucosal breaks in patients with different grades of reflux esophagitis.
      • Katsube T.
      • Adachi K.
      • Furuta K.
      • et al.
      Difference in localization of esophageal mucosal breaks among grades of esophagitis.
      In that investigation, we found that the mucosal breaks of low-grade esophagitis occurred mainly on the right anterior wall of the distal esophagus. Our observation was later confirmed in 2007 by Edebo et al.
      • Edebo A.
      • Vieth M.
      • Tam W.
      • et al.
      Circumferential and axial distribution of esophageal mucosal damage in reflux disease.
      We also investigated the asymmetrical circumferential distribution of SSBE with tonguelike configurations and in 2008 reported that tonguelike SSBE were mainly found on the right anterior side wall of the esophagus.
      • Okita K.
      • Amano Y.
      • Takahashi Y.
      • et al.
      Barrett's esophagus in Japanese patients: its prevalence, form, and elongation.
      In 2006, we examined the localization of early-stage neoplastic Barrett's lesions in patients with SSBE and reported their predominant distribution on the right anterior wall of the esophagus.
      • Moriyama N.
      • Amano Y.
      • Okita K.
      • et al.
      Localization of early-stage dysplastic Barrett's lesions in patients with short-segment Barrett's esophagus.
      That finding was soon confirmed in 2007 by Pech et al.
      • Pech O.
      • Gossner L.
      • Manner H.
      • et al.
      Prospective evaluation of the macroscopic types and location of early Barrett's neoplasia in 380 lesions.
      In addition to reflux esophagitis and Barrett's adenocarcinomas, we investigated the circumferential distribution of ruptured esophageal varices as possible acid-related lesions. The administration of proton pump inhibitors has been repeatedly reported to decrease the risk of esophageal variceal rupture, whereas esophageal acid reflux has been speculated to induce esophageal erosions and rupture of the varices. In our study population, high-grade esophageal varices with risk of rupture were most frequently found on the right posterior wall of the distal esophagus. However, it is quite interesting that ruptured esophageal varices were most frequently found on the right anterior wall of the esophagus.
      • Okamoto E.
      • Amano Y.
      • Fukuhara H.
      • et al.
      Does gastroesophageal reflux have an influence on bleeding from esophageal varices?.
      These findings, including the predominant right anterior localization of mucosal breaks of reflux esophagitis, tonguelike SSBE lesions, Barrett's neoplasia, and ruptured esophageal varices, suggest the presence of right anterior predominant gastroesophageal acid reflux in the distal esophagus. To investigate the radially asymmetrical distribution of gastroesophageal acid reflux, we developed a novel pH sensor catheter equipped with 8 pH sensors on its surface and have studied acid exposure time in different radial walls of the esophagus in patients with reflux esophagitis.
      • Kinoshita Y.
      • Furuta K.
      • Adachi K.
      • et al.
      Asymmetrical circumferential distribution of esophagogastric junctional lesions: anatomical and physiological considerations.
      • Ohara S.
      • Furuta K.
      • Adachi K.
      • et al.
      Radially asymmetric gastroesophageal acid reflux in the distal esophagus: examinations with novel pH sensor catheter equipped with 8 pH sensors.
      By using our device, we found that acid reflux was most prominent on the right anterior wall of the esophagus and nicely coincided with the locations of mucosal breaks in individual patients. The mechanism by which gastric acid reflux occurs mainly on the right anterior wall of the distal esophagus has not been completely clarified. Nevertheless, the asymmetrical compression pressure produced by the lower esophageal sphincter and diaphragmatic hiatus may play a role in the asymmetrical reflux of gastric contents.
      In their study, Cassani et al
      • Cassani L.
      • Sumner E.
      • Slaughter J.C.
      • et al.
      Directional distribution of neoplasia in Barrett's esophagus is not influenced by distance from the gastroesophageal junction.
      extended this concept from the distal esophagus to the more proximal esophagus and found that Barrett's neoplasia associated with LSBE was also predominantly present on the right anterior wall of the esophagus. An interesting point about their study, which is open for possible discussion, is the method used to divide the patients into 2 groups: neoplasia associated with SSBE and that with LSBE, based on the conventional point 3 centimeters above the lower esophageal sphincter. In the upper portion of the esophagus, more than 3 centimeters above the LES, refluxed gastric contents are expected to be more uniformly distributed in all circumferential directions of the esophagus. Therefore, in the upper esophagus, the asymmetrical distribution of Barrett's neoplasia may be difficult to locate. We consider that an investigation focusing only on Barrett's neoplasia in the upper esophagus (for example, 5-10 cm above the lower esophageal sphincter) would be quite interesting and may reveal important information about the endoscopic surveillance of LSBE cases. If an asymmetrical distribution of Barrett's esophagus is found even in the upper portion of the esophagus, it may be caused not by an uneven reflux of gastric acid but rather by different mechanisms such as uneven flow of swallowed saliva and uneven chemical clearance in the esophagus.
      We applaud the effort of Cassani et al, who have provided an extension of previous observations of the distal esophagus to the middle part of the esophagus.

      Disclosure

      All authors disclosed no financial relationships relevant to this publication.

      References

        • Cassani L.
        • Sumner E.
        • Slaughter J.C.
        • et al.
        Directional distribution of neoplasia in Barrett's esophagus is not influenced by distance from the gastroesophageal junction.
        Gastrointest Endosc. 2013; 77: 877-882
        • Katsube T.
        • Adachi K.
        • Furuta K.
        • et al.
        Difference in localization of esophageal mucosal breaks among grades of esophagitis.
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        • Edebo A.
        • Vieth M.
        • Tam W.
        • et al.
        Circumferential and axial distribution of esophageal mucosal damage in reflux disease.
        Dis Esophagus. 2007; 20: 232-238
        • Okita K.
        • Amano Y.
        • Takahashi Y.
        • et al.
        Barrett's esophagus in Japanese patients: its prevalence, form, and elongation.
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        • Moriyama N.
        • Amano Y.
        • Okita K.
        • et al.
        Localization of early-stage dysplastic Barrett's lesions in patients with short-segment Barrett's esophagus.
        Am J Gastroenterol. 2006; 101: 2666-2667
        • Pech O.
        • Gossner L.
        • Manner H.
        • et al.
        Prospective evaluation of the macroscopic types and location of early Barrett's neoplasia in 380 lesions.
        Endoscopy. 2007; 39: 588-593
        • Okamoto E.
        • Amano Y.
        • Fukuhara H.
        • et al.
        Does gastroesophageal reflux have an influence on bleeding from esophageal varices?.
        J Gastroenterol. 2008; 43: 803-808
        • Kinoshita Y.
        • Furuta K.
        • Adachi K.
        • et al.
        Asymmetrical circumferential distribution of esophagogastric junctional lesions: anatomical and physiological considerations.
        J Gastroenterol. 2009; 44: 812-818
        • Ohara S.
        • Furuta K.
        • Adachi K.
        • et al.
        Radially asymmetric gastroesophageal acid reflux in the distal esophagus: examinations with novel pH sensor catheter equipped with 8 pH sensors.
        J Gastroenterol. 2012; 47: 1221-1227

      Linked Article

      • Directional distribution of neoplasia in Barrett's esophagus is not influenced by distance from the gastroesophageal junction
        Gastrointestinal EndoscopyVol. 77Issue 6
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          Accurate endoscopic detection and staging are critical for appropriate management of Barrett's esophagus (BE)–associated neoplasia. Prior investigation has demonstrated that the distribution of endoscopically detectable early neoplasia is not uniform but instead favors specific directional distributions within a short BE segment; however, it is unknown whether the directional distribution of neoplasia differs with increasing distance from the gastroesophageal junction, including in patients with long-segment BE.
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      • Response
        Gastrointestinal EndoscopyVol. 79Issue 1
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          We thank Drs Ishimura, Ishihara, and Kinoshita for their insightful comments on our study of directional preference of Barrett's associated neoplasia.
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