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Keywords:

  • acid pocket;
  • gastrectomy;
  • gastric antrum;
  • gastroesophageal reflux

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgments
  9. Author’s contribution
  10. References

Background  An unbuffered postprandial proximal gastric acid pocket (PPGAP) has been noticed in the majority of normal individuals and patients with gastroesophageal reflux disease. The role of gastric anatomy, specifically the antrum, in the physiology of the PPGAP is not yet fully elucidated. This study aims to analyze the presence of PPGAP in patients submitted to distal gastrectomy.

Methods  A total of 15 patients who had a distal gastrectomy plus DII lymphadenectomy and Roux-en-Y reconstruction for gastric adenocarcinoma (mean age 64.3 ± 8.4 years, 12 females) were studied. All patients were free of foregut symptoms after the operation. Patients underwent a high-resolution manometry. A station pull-through pH monitoring was performed from 5 cm below the lower border of the lower esophageal sphincter (LBLES) to the LBLES in increments of 1 cm in a fasting state and 10 min after a standardized fatty meal. Postprandial proximal gastric acid pocket was defined by the presence of acid reading (pH<4) in a segment of the proximal stomach between non-acid segments distally (food) and proximally (LBLES). The PPGAP extent was recorded. The protocol was approved by local ethics committee.

Key Results  Acidity was not detected in the stomach of nine patients before meal. After meal, PPGAP was not found in three patients. In three patients (20%), a PPGAP was noted with an extension of 1, 1 and 3 cm.

Conclusions & Inferences  In conclusion, PPGAP is present in a minority of patients after distal gastrectomy; this finding may suggest that the gastric antrum may play a role in the genesis of the PPGAP.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgments
  9. Author’s contribution
  10. References

An unbuffered postprandial proximal gastric acid pocket (PPGAP) has been noticed in the majority of normal individuals and patients with gastroesophageal reflux disease (GERD)1–3 but in only 20% of patients after exclusion of the gastric fundus as in patients submitted to Roux-en-Y gastric bypass.4 The role of gastric anatomy, specifically the antrum, in the physiology of the PPGAP is not yet fully elucidated.

This study aims to analyze the presence and extent of PPGAP in patients after distal gastrectomy.

Materials and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgments
  9. Author’s contribution
  10. References

Population

Fifteen patients who underwent a distal gastrectomy plus DII lymphadenectomy and Roux-en-Y reconstruction for gastric adenocarcinoma [mean age 64.3 ± 8.4 years (range 47–75), 12 females] were studied. All tumors were located in the lower part of the stomach according to the Japanese Gastric Cancer Association guidelines. Vagotomy was not added to the procedure although vagal nerves originated from the posterior vagus nerve are harvested during dissection of lymph node station #1 (right paracardial). The mean time from operation was 5.1 ± 4.4 years (range 3 months–13 years). All patients were free of foregut symptoms after the operation. No individual was in use of antacid medication. No evidence of recurrent disease was noticed and patients were not on chemoradiotherapy.

Patients were excluded in the following situations: (i) foregut surgery other than the gastrectomy, (ii) denial to participate in the study, and (iii) operation less than 3 months before the study.

Esophageal tests

All individuals underwent a high resolution manometry (Sierra Instruments, Los Angeles, CA, USA) to assess esophageal body motility and identify the location of the lower border of the lower esophageal sphincter (LBLES) according to previously described methodology.5 Data acquisition and analyses were accomplished with the dedicated software (Sierra Instruments).

A station pull-through pH monitoring (Alacer biomedica, Sao Paulo, SP, Brazil) was performed following Fletcher et al. original description of the method for PPGAP analysis.1 It started 5 cm below the LBLES up to the LBLES in increments of 1 cm signaled by pushing the event bottom in a fasting state. The pH catheter was replaced 5 cm below the LBLES and the pull-through repeated 10 min after a standardized fatty meal (100 g hamburger, 10% fat + 200 mL of chocolate milk, 10% fat).

All tests were performed by the same investigator experienced in esophageal function tests.

Postprandial proximal gastric acid pocket

Postprandial proximal gastric acid pocket was defined by the presence of acid reading (pH<4) in a segment of the proximal stomach between non-acid segments distally (food) and proximally (LBLES). The PPGAP extent was recorded.

Ethics

The protocol was approved by local ethics committee. Informed consent was obtained from all individuals.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgments
  9. Author’s contribution
  10. References

Lower esophageal sphincter (LES) basal pressure (mean respiratory) was 26.6 ± 23.5 (range 1–96) mmHg. Three patients had a hypotonic LES and two had a hypertonic LES. All but one patient had abnormal peristalsis (60% of peristaltic waves). Distal esophageal amplitude at 3 cm above the LES was 86.6 ± 62.1 (range 27–191) mmHg. Five patients had hypocontractility and three had hypercontractility.

Acid was not detected in the studied area of the stomach in nine (60%) patients. After meal, PPGAP was not found in three (20%) patients. Postprandial proximal gastric acid pocket was detected in three (20%) patients with extensions of 1, 1 and 2 cm.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgments
  9. Author’s contribution
  10. References

Our results show that a PPGA is present in 20% of the patients submitted to distal gastrectomy.

Postprandial proximal gastric acid pocket

Postprandial episodes of gastroesophageal reflux occur frequently in patients with GERD and normal individuals.6 This paradox found in the evaluation of patients with GERD was explained by Fletcher et al. in 2001.1 The authors showed the presence of an unbuffered layer of acid below the gastroesophageal junction floating above the ingested food that escapes the buffering effect of the meal.1 The genesis of the PPGAP may be linked to gastric motility and gastric anatomy.

Postprandial proximal gastric acid pocket and gastric anatomy

Gastric pH monitoring shows a non-homogeneous pH distribution in the stomach after meals.7,8 Furthermore, a PPGAP is kept in the same position irrespective of body position.3,8 These findings suggest that the PPGAP is not only based on a physical principal of a hydrophilic acid floating over a lipophilic meal or gravity. Gastric anatomy and physiology must be contributory to the PPGAP genesis as it is a common finding in individuals with an intact stomach with or without GERD, given that different studies reported a prevalence of 100%,1–3 but in only 20% of patients after postoperative alteration of the gastric fundus, such as after Roux-en-Y gastric bypass4 or Nissen fundoplication.9

The absence of the antrum may lead to acid reduction due to decrease in gastrin levels but we believe that the PPGAP genesis is linked to acid reflux in the subcardial area not acid production. For that matter, gastrin levels were not determined. The stomach has two distinct physiologic motor areas: the proximal stomach and the distal stomach, with a clear proximal-distal segmentation.10 The proximal part is relatively quiescent after a meal allowing acid to remain longer in this area.1 We were unable to correlate PPGAP and proximal gastric pressures in patients after distal gastrectomy showing that the lack of the antrum probably does not change proximal gastric motility.11 However, a distal to proximal acid reflux occur independent of the body position12 that may bath the subcardial area with acid after the acidity in this area is buffered by food. Antrectomy may prevent this proximal-distal reflux to occur. Very interestingly, we found in 60% of the patients that the acid was in the distal part of the remnant stomach but not in the studied area.

Conclusions

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgments
  9. Author’s contribution
  10. References

In conclusion, PPGAP is not a common finding in patients after distal gastrectomy leading to the speculation that the gastric antrum plays a role in the PPGAP genesis.

Acknowledgments

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgments
  9. Author’s contribution
  10. References

The study was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) grant # 2007/07940-8.

We are indebted to Ms. Mirian Wolfarth for her invaluable technical assistance with the esophageal tests.

Author’s contribution

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgments
  9. Author’s contribution
  10. References

FAMH contributed to the conception and design; FAMH, FPPV, and LCS contributed to the acquisition of data, analysis and interpretation of data, and approved the final version to be published; MGP reviewed for intellectual content and approved the final version to be published.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgments
  9. Author’s contribution
  10. References
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    Herbella FA, Vicentine FP, Del Grande JC et al. Postprandial proximal gastric acid pocket after laparoscopic Nissen fundoplication. Surg Endosc, in press.
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