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The position of the acid pocket as a major risk factor for acidic reflux in healthy subjects and patients with GORD
  1. Hanneke Beaumont1,
  2. Roelof J Bennink2,
  3. Jan de Jong2,
  4. Guy E Boeckxstaens1,3
  1. 1Academic Medical Center, Department of Gastroenterology and Hepatology, Amsterdam, The Netherlands
  2. 2Academic Medical Center, Department of Nuclear Medicine, Amsterdam, The Netherlands
  3. 3Department of Gastroenterology, University Hospital Leuven, Catholic University of Leuven, Leuven, Belgium
  1. Correspondence to G E Boeckxstaens, Department of Gastroenterology, Catholic University of Leuven, University Hospital Leuven, Herestraat 49, 3000 Leuven, Belgium; guy.boeckxstaens{at}


Introduction Gastro-oesophageal reflux occurs twice as much during transient lower oesophageal sphincter relaxations (TLOSRs) in patients with gastro-oesophageal reflux disease (GORD) compared to healthy volunteers (HVs). Our aim was to assess whether the localisation of the postprandial acid pocket and its interaction with a hiatal hernia (HH) play a role in the occurrence of acidic reflux during TLOSRs.

Methods Ten HVs and 22 patients with GORD (12 with HH<3 cm (s-HH), 10 with HH≥3 cm (l-HH)) were studied. The squamocolumnar junction and diaphragmatic impression were marked with a radioactively labelled clip. To visualise the acid pocket, 99mTc-pertechnetate was injected intravenously and images were acquired up to 2 h postprandial. Concurrently, combined manometry/impedance and four-channel pH-metry were performed, with pH pull-through at multiple time-points.

Results The rate of TLOSRs and the per cent associated with reflux was comparable between all groups. However, acidic reflux was significantly increased in patients, especially in patients with l-HH. Acid pocket length was significantly enlarged in patients. Moreover, immediately before a TLOSR, the acid pocket was more frequently located within the hiatus or above the diaphragm in patients with GORD (s-HH, 54%; l-HH, 77%) compared to HVs (22% of TLOSRs). Acidic reflux was significantly increased when the acid pocket was located above the diaphragm in all groups compared to a sub-diaphragmatic localisation.

Conclusion The position of the acid pocket is largely determined by the presence of a HH. Entrapment of the pocket above the diaphragm, especially in patients with l-HH, is a major risk factor underlying the increased occurrence of acidic reflux during a TLOSR in patients with GORD.

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  • Funding HB is supported by an unrestricted grant from AstraZeneca. GEB is supported by a grant (Odysseus program, G.0905.07) of the Flemish “Fonds Wetenschappelijk Onderzoek” (FWO).

  • Competing interests None.

  • Ethics approval The study was approved by the Medical Ethics Committee of the Academic Medical Center, Amsterdam.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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