Subcardial 24-h wireless pH monitoring in gastroesophageal reflux disease patients with and without hiatal hernia compared with healthy subjects

The views of African and Middle Eastern Gastroenterologists on the management of mild-to-moderate, non-erosive gastro-esophageal reflux disease (GERD)

INTRODUCTION

Gastro-esophageal reflux disease (GERD) is a common gastrointestinal disorder that occurs when backflow of the gastric contents into the esophagus results in troublesome symptoms. Though GERD has been extensively studied in Western populations, literature on the management of GERD in patients in Africa and Middle East (AME) is scarce.

AREAS COVERED

In this review, we provide an overview of the management of mild-to-moderate GERD in AME. Here we focus on the efficacy and safety of currently available treatments for GERD to help physicians and community pharmacists appropriately manage patients with mild-to-moderate GERD in the primary healthcare setting, detailing specific situations and patient scenarios that are relevant to the region, including management of GERD during Ramadan and post-bariatric surgery.

EXPERT OPINION

Under-appreciation of the burden of GERD in the region has resulted in a lack of consensus on management. Barriers that currently prevent the adoption of treatment guidelines in the primary healthcare setting may include lack of availability of local guidelines and referral systems, a paucity of region-specific research, and dogmatic adherence to traditional practice. By increasing awareness, strengthening knowledge, and by more effective utilization of resources, physicians and pharmacists could optimize GERD management strategies to better support patients.

Postprandial proximal gastric acid pocket and its association with gastroesophageal acid reflux in patients with short-segment Barrett's esophagus

OBJECTIVE

To determine the characteristics of postprandial proximal gastric acid pockets (PPGAPs) and their association with gastroesophageal acid reflux in patients with Barrett's esophagus (BE).

METHODS

Fifteen patients with BE (defined by columnar lined esophagus of ≥1 cm) and 15 healthy individuals that were matched for age, gender, and body mass index, were recruited. The fasting intragastric pH and the appearance time, length, lowest pH, and mean pH of the PPGAP were determined using a single pH electrode pull-through experiment. For BE patients, a gastroesophageal reflux disease questionnaire (GerdQ) was completed and esophageal 24-h pH monitoring was carried out.

RESULTS

The PPGAP was significantly longer (5 (3, 5) cm vs. 2 (1, 2) cm) and the lowest pH (1.1 (0.8, 1.5) vs. 1.6 (1.4, 1.9)) was significantly lower in patients with short-segment BE than in healthy individuals. The PPGAP started to appear proximally from the gastroesophageal pH step-up point to the esophageal lumen. The acidity of the PPGAP was higher in the distal segment than in the proximal segment. In short-segment BE patients, there were significant correlations between the acidity and the appearance time and length of the PPGAP. The length and acidity of the PPGAP were positively associated with gastroesophageal acid reflux episodes. The acidity of the PPGAP was associated with the DeMeester scores, the GerdQ scores, and the fasting intragastric pH.

CONCLUSIONS

In patients with short-segment BE, a PPGAP is commonly seen. Its length and acidity of PPGAP are associated with gastroesophageal acid reflux, the DeMeester score, and the GerdQ score in patients with short-segment BE.

Concomitant use of capecitabine and proton pump inhibitors – Is it safe?

Background

Capecitabine is a commonly used oral chemotherapy agent. Recent data suggest that concurrent use of proton pump inhibitors may reduce the efficacy of capecitabine by decreasing its absorption through increased gastric pH. Since proton pump inhibitors are widely used, we evaluated the supportive evidence for the probability of occurrence and potential seriousness of this drug interaction.

Methods

The probability of occurrence was evaluated based on the clinical, pharmacokinetic and in vitro evidence using the Drug Interaction Probability Scale. The possibility of seriousness was assessed based on the potential impact on the therapeutic intent of capecitabine therapy.

Results

The probability of occurrence of the interaction is doubtful. Clinical findings from two retrospective post hoc analyses showed inconsistent trends towards reduced survival. Pharmacokinetics studies found no significant decrease in systemic capecitabine level with concurrent gastric acid suppression with antacid or food intake. In vitro data do not support the proposed mechanism of reduced capecitabine absorption due to increased gastric pH. The possibility of seriousness varies depending on the treatment intent of capecitabine therapy. The most and least serious possible outcome would be reduced possibility of cure or survival and symptom control, respectively.

Conclusion

Although the possible outcome may be serious, the probability of interaction between capecitabine and proton pump inhibitors is doubtful. Therefore, we suggest that intervention should be limited to minimal change to existing therapy plan. This may include routinely ascertaining the need for proton pump inhibitor use. Alternate acid suppressing agents may be considered based on the therapeutic intent of capecitabine therapy.

The Role of the Acid Pocket in Gastroesophageal Reflux Disease

Gastroesophageal reflux disease is one of the commonest chronic conditions in the western world and its prevalence is increasing worldwide. The discovery of the acid pocket explained the paradox of acid reflux occurring more frequently in the postprandial period despite intragastric acidity being low due to the buffering effect of the meal. The acid pocket was first described in 2001 when it was detected as an area of low pH immediately distal to the cardia using dual pH electrode pull-through studies 15 minutes after a meal. It was hypothesized that there was a local pocket of acid close to the gastroesophageal junction that escapes the buffering effect of the meal, and that this is the source of postprandial acidic reflux. The presence of the acid pocket has been confirmed in other studies using different techniques including high-resolution pHmetry, Bravo capsule, magnetic resonance imaging, and scintigraphy. This review aims to describe what we know about the acid pocket including its length, volume, fluid constituents, and its relationship to the lower esophageal sphincter and squamocolumnar junction. We will discuss the possible mechanisms that lead to the formation of the acid pocket and examine what differences exist in patients who suffer from acid reflux. Treatments for reflux disease that affect the acid pocket will also be discussed.

The postprandial acid pocket does not extend into most distal esophagus: evidence from pH studies performed immediately above the squamocolumnar junction

OBJECTIVE

The postprandial acid pocket is suggested to be an important factor in the pathogenesis of gastroesophageal reflux disease (GERD) as it according to the theory extends into the distal esophagus. The aim of this study was to test the hypothesis that the acid pocket transverses the squamocolumnar junction (SCJ) and exposes the most distal esophagus to gastric acid for extended periods following a meal.

MATERIAL AND METHODS

Fifty asymptomatic volunteers and 75 patients with GERD underwent 48-h pH monitoring with the electrode of a pH capsule placed immediately above the SCJ. The characteristics of esophageal acid exposure from the 90-min postprandial periods were compared with those observed during the upright, preprandial periods.

RESULTS

In asymptomatic controls, the degree of postprandial esophageal acid exposure was similar to that observed in the preprandial periods (median % time with pH <4, 2.2 vs. 2.6, p = 0.165). In contrast, symptomatic patients had significantly greater acid exposure in the postprandial compared with the preprandial periods (median % time with pH <4, 15.5 vs. 8.5, p < 0.001). The higher degree of acid exposure during the postprandial periods was due to a significantly higher number of short reflux episodes and reflux events with long durations were infrequent.

CONCLUSION

Postprandial acid exposure in the most distal esophagus was characterized by numerous short reflux events, and reflux events of long durations were rare. Our observations suggest that the acid pocket is confined to the stomach, questioning the importance of the acid pocket in GERD.

The acid pocket: a target for treatment in reflux disease?

The nadir esophageal pH of reflux observed during pH monitoring in the postprandial period is often more acidic than the concomitant intragastric pH. This paradox prompted the discovery of the "acid pocket", an area of unbuffered gastric acid that accumulates in the proximal stomach after meals and serves as the reservoir for acid reflux in healthy individuals and gastroesophageal reflux disease (GERD) patients. However, there are differentiating features between these populations in the size and position of the acid pocket, with GERD patients predisposed to upward migration of the proximal margin onto the esophageal mucosa, particularly when supine. This upward migration of acid, sometimes referred to as an "acid film", likely contributes to mucosal pathology in the region of the squamocolumnar junction. Furthermore, movement of the acid pocket itself to a supradiaphragmatic location with hiatus hernia increases the propensity for acid reflux by all conventional mechanisms. Consequently, the acid pocket is an attractive target for GERD therapy. It may be targeted in a global way with proton pump inhibitors that attenuate acid pocket development, or with alginate/antacid combinations that colocalize with the acid pocket and displace it distally, thereby demonstrating the potential for selective targeting of the acid pocket in GERD.

Advances in diagnostic testing for gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) contributes substantially to morbidity and to costs in the United States health care system. The burden of this disease has resulted in attempts at improving diagnosis and characterizing patients. Numerous research and technical advances have enhanced our understanding of both the utility and limitations of a variety of diagnostic modalities. The purpose of this review is to highlight recent advances in GERD diagnostic testing and to discuss their implications for use in clinical practice. Topics addressed include esophageal pH monitoring, impedance testing, symptom association analyses, narrow-band imaging, and histopathology.

Clinical trial: gastric acid suppression in Hispanic adults with symptomatic gastro-oesophageal reflux disease - comparator study of esomeprazole, lansoprazole and pantoprazole

BACKGROUND

Hispanic-Americans are a rapidly growing population in the United States, yet gastro-oesophageal reflux disease (GERD) is not well studied in this population.

AIM

To compare the efficacy of esomeprazole, lansoprazole and pantoprazole in suppressing gastric acid, including the area of the 'acid pocket,' in Hispanics with GERD.

METHODS

In this open-label, 3-way crossover study, 83 Hispanics with symptomatic GERD were randomized to 1 of 6 possible treatment sequences of three 5-7-day dosing periods with esomeprazole 40 mg, lansoprazole 30 mg and pantoprazole 40 mg daily separated by 10-17-day washout periods. Intragastric pH was measured for 24 h using dual probes with a distal and proximal (area of the 'acid pocket') electrode.

RESULTS

Esomeprazole suppressed intragastric acid (pH >4.0) significantly longer over 24 h (primary end point) compared with lansoprazole and pantoprazole (P < 0.0001), and proximal gastric acid (pH >4.0) significantly longer over 24 h compared with lansoprazole (P < 0.05) and pantoprazole (P < 0.0001).

CONCLUSIONS

Esomeprazole was more effective than lansoprazole and pantoprazole in suppressing gastric acidity at both intragastric distal and proximal (area of the acid pocket) sites in Hispanics with GERD. Future studies are warranted to understand better the role of the acid pocket in GERD (Clinical trial numbers: D9612L00106; ClinicalTrials.gov: NCT00410592).