Failure of oesophageal acid control in candidates for Barrett's oesophagus reversal on a very high dose of proton pump inhibitor

The Discrepancy Between Subjective and Objective Clinical Endpoints in Gastroesophageal Reflux Disease

Therapeutic outcome in gastroesophageal reflux disease (GERD) is commonly determined by both subjective and objective clinical endpoints. Clinicians frequently use symptom improvement as a key benchmark of clinical success, in conjunction with normalization of objective parameters such as esophageal acid exposure and inflammation. However, GERD therapeutic trials have demonstrated that a substantial number of patients rendered asymptomatic, whether through medical, surgical, or endoscopic intervention, continue to have persistent abnormal esophageal acid exposure and erosive esophagitis. The opposite has also been demonstrated in therapeutic trials, where patients remained symptomatic despite normalization of esophageal acid exposure and complete resolution of esophageal inflammation. Moreover, there is no substantive evidence that symptomatic response to antireflux treatment requires complete esophageal mucosal healing or normalization of esophageal acid exposure. Thus, it appears that a certain level of improvement in objective parameters is needed to translate into meaningful changes in symptoms and health-related quality of life of GERD patients. This supports the need to reconsider the commonly used "hard" clinical endpoints to evaluate therapeutic trials in GERD.

ESNM/ANMS consensus paper: Diagnosis and management of refractory gastro-esophageal reflux disease

Up to 40% of patients with symptoms suspicious of gastroesophageal reflux disease (GERD) do not respond completely to proton pump inhibitor (PPI) therapy. The term "refractory GERD" has been used loosely in the literature. A distinction should be made between refractory symptoms (ie, symptoms may or may not be GERD-related), refractory GERD symptoms (ie, persisting symptoms in patients with proven GERD, regardless of relationship to ongoing reflux), and refractory GERD (ie, objective evidence of GERD despite adequate medical management). The present ESNM/ANMS consensus paper proposes use the term "refractory GERD symptoms" only in patients with persisting symptoms and previously proven GERD by either endoscopy or esophageal pH monitoring. Even in this context, symptoms may or may not be reflux related. Objective evaluation, including endoscopy and esophageal physiologic testing, is requisite to provide insights into mechanisms of symptom generation and evidence of true refractory GERD. Some patients may have true ongoing refractory acid or weakly acidic reflux despite PPIs, while others have no evidence of ongoing reflux, and yet others have functional esophageal disorders (overlapping with proven GERD confirmed off therapy). In this context, attention should also be paid to supragastric belching and rumination syndrome, which may be important contributors to refractory symptoms.

Interaction of epidermal growth factor with COX-2 products and peroxisome proliferator-activated receptor-γ system in experimental rat Barrett's esophagus

Mixed acidic-alkaline refluxate is a major pathogenic factor in chronic esophagitis progressing to Barrett's esophagus (BE). We hypothesized that epidermal growth factor (EGF) can interact with COX-2 and peroxisome proliferator-activated receptor-γ (PPARγ) in rats surgically prepared with esophagogastroduodenal anastomosis (EGDA) with healthy or removed salivary glands to deplete salivary EGF. EGDA rats were treated with 1) vehicle, 2) EGF or PPARγ agonist pioglitazone with or without EGFR kinase inhibitor tyrphostin A46, EGF or PPARγ antagonist GW9662 respectively, 3) ranitidine or pantoprazole, and 4) the selective COX-2 inhibitor celecoxib combined with pioglitazone. At 3 mo, the esophageal damage and the esophageal blood flow (EBF) were determined, the mucosal expression of EGF, EGFR, COX-2, TNFα, and PPARγ mRNA and phospho-EGFR/EGFR protein was analyzed. All EGDA rats developed chronic esophagitis, esophageal ulcerations, and intestinal metaplasia followed by a fall in the EBF, an increase in the plasma of IL-1β, TNFα, and mucosal PGE₂ content, the overexpression of COX-2-, and EGF-EGFR mRNAs, and proteins, and these effects were aggravated by EGF and attenuated by pioglitazone. The rise in EGF and COX-2 mRNA was inhibited by pioglitazone but reversed by pioglitazone cotreated with GW9662. We conclude that 1) EGF can interact with PG/COX-2 and the PPARγ system in the mechanism of chronic esophagitis; 2) the deleterious effect of EGF involves an impairment of EBF and the overexpression of COX-2 and EGFR, and 3) agonists of PPARγ and inhibitors of EGFR may be useful in the treatment of chronic esophagitis progressing to BE.NEW & NOTEWORTHY Rats with EGDA exhibited chronic esophagitis accompanied by a fall in EBF and an increase in mucosal expression of mRNAs for EGF, COX-2, and TNFα, and these effects were exacerbated by exogenous EGF and reduced by removal of a major source of endogenous EGF with salivectomy or concurrent treatment with tyrphostin A46 or pioglitazone combined with EGF. Beneficial effects of salivectomy in an experimental model of BE were counteracted by PPARγ antagonist, whereas selective COX-2 inhibitor celecoxib synergistically with pioglitazone reduced severity of esophageal damage and protected esophageal mucosa from reflux. We propose the cross talk among EGF/EGFR, PG/COX-2, and proinflammatory cytokines with PPARγ pathway in the mechanism of pathogenesis of chronic esophagitis progressing to BE and EAC.

The potential role of potassium-competitive acid blockers in the treatment of gastroesophageal reflux disease

PURPOSE OF REVIEW

Gastroesophageal reflux disease (GERD) is primarily a motor disorder, but its pathogenesis is multifactorial. Although gastric acid secretion is usually normal in GERD patients, treatment with proton pump inhibitors (PPIs) has become the standard of care, despite increasing awareness of their shortcomings. In this article, a new class of antisecretory drugs (namely potassium-competitive acid blockers, P-CABs), developed to overcome these limitations, is discussed.

RECENT FINDINGS

P-CABs block the K exchange channel of the proton pump, resulting in rapid, competitive, reversible inhibition of acid secretion. These drugs offer a more rapid elevation of intragastric pH than PPIs, while maintaining similar antisecretory effect, the duration of which is dependent on half-life and can be prolonged with extended release formulations. Thus, P-CABs offer advances in the treatment of GERD including rapid heartburn relief, faster and more reliable healing of severe grades of erosive esophagitis, as a consequence of better control of nighttime acid secretion than PPIs.

SUMMARY

P-CABs overcome many of the drawbacks of PPIs. The unique antisecretory effects of vonoprazan might be especially useful in the long-term treatment of patients with Barrett's esophagus.

Impact of gastroesophageal reflux control through tailored proton pump inhibition therapy or fundoplication in patients with Barrett’s esophagus

AIM

To determine the impact of upwards titration of proton pump inhibition (PPI) on acid reflux, symptom scores and histology, compared to clinically successful fundoplication.

METHODS

Two cohorts of long-segment Barrett’s esophagus (BE) patients were studied. In group 1 (n = 24), increasing doses of PPI were administered in 8-wk intervals until acid reflux normalization. At each assessment, ambulatory 24 h pH recording, endoscopy with biopsies and symptom scoring (by a gastroesophageal reflux disease health related quality of life questionnaire, GERD/HRLQ) were performed. Group 2 (n = 30) consisted of patients with a previous fundoplication.

RESULTS

In group 1, acid reflux normalized in 23 of 24 patients, resulting in improved GERD/HRQL scores (P = 0.001), which were most pronounced after the starting dose of PPI (P < 0.001). PPI treatment reached the same level of GERD/HRQL scores as after a clinically successful fundoplication (P = 0.5). Normalization of acid reflux in both groups was associated with reduction in papillary length, basal cell layer thickness, intercellular space dilatation, and acute and chronic inflammation of squamous epithelium.

CONCLUSION

This study shows that acid reflux and symptom scores co-vary throughout PPI increments in long-segment BE patients, especially after the first dose of PPI, reaching the same level as after a successful fundoplication. Minor changes were found among GERD markers at the morphological level.

Predictors of proton pump inhibitor failure in non-erosive reflux disease: A study with impedance-pH monitoring and high-resolution manometry

BACKGROUND

Approximately one-third of gastroesophageal reflux disease (GERD) patients have symptoms resistant to proton pump inhibitor (PPI). We used the high-resolution manometry (HRM) and multichannel intraluminal impedance-pH (MII-pH) monitoring to investigate potential predictors of PPI failure in non-erosive reflux disease (NERD) patients.

METHODS

One hundred and seventeen NERD patients were included, within which there were 44 PPI failure patients. The symptomatic questionnaire GerdQ, HRM and 24-hour MII-pH monitoring were performed before PPI therapy. PPI failure was defined as persistent reflux symptoms for more than 1 day during the last week on esomeprazole (20 mg twice daily) for continuous 4 weeks. The predictors for PPI failure were investigated by multivariable logistic regression analysis.

KEY RESULTS

Proton pump inhibitor failure patients had lower body mass index (BMI) and more concomitant functional dyspepsia (FD) symptoms. PPI failure patients had a higher percentage of type I esophagogastric junction (EGJ) morphology (p = 0.005), increased EGJ augmentation (p = 0.000), higher prevalence of esophageal motility disorders (p = 0.005) and a higher ratio of negative symptom index (SI, p = 0.000). Multivariable regression analysis showed that concomitance of FD symptoms, EGJ augmentation and negative SI were independent risk factors for PPI failure in NERD.

CONCLUSIONS & INFERENCES

Approximately half of PPI failure patients were found to have esophageal motility disorders in HRM. The independent risk factors for PPI failure in NERD were concomitant FD symptoms, increased EGJ augmentation and negative SI.

Unmet Needs in the Treatment of Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is a highly prevalent gastrointestinal disorder. Proton pump inhibitors have profoundly revolutionized the treatment of GERD. However, several areas of unmet need persist despite marked improvements in the ther-apeutic management of GERD. These include the advanced grades of erosive esophagitis, nonerosive reflux disease, main-tenance treatment of erosive esophagitis, refractory GERD, postprandial heartburn, atypical and extraesophageal manifestations of GERD, Barrett's esophagus, chronic protein pump inhibitor treatment, and post-bariatric surgery GERD. Consequently, any fu-ture development of novel therapeutic modalities for GERD (medical, endoscopic, or surgical), would likely focus on the afore-mentioned areas of unmet need.

Australian clinical practice guidelines for the diagnosis and management of Barrett's esophagus and early esophageal adenocarcinoma

Barrett's esophagus (BE), a common condition, is the only known precursor to esophageal adenocarcinoma (EAC). There is uncertainty about the best way to manage BE as most people with BE never develop EAC and most patients diagnosed with EAC have no preceding diagnosis of BE. Moreover, there have been recent advances in knowledge and practice about the management of BE and early EAC. To aid clinical decision making in this rapidly moving field, Cancer Council Australia convened an expert working party to identify pertinent clinical questions. The questions covered a wide range of topics including endoscopic and histological definitions of BE and early EAC; prevalence, incidence, natural history, and risk factors for BE; and methods for managing BE and early EAC. The latter considered modification of lifestyle factors; screening and surveillance strategies; and medical, endoscopic, and surgical interventions. To answer each question, the working party systematically reviewed the literature and developed a set of recommendations through consensus. Evidence underpinning each recommendation was rated according to quality and applicability.

Impairment of secondary peristalsis in Barrett’s esophagus by transnasal endoscopy-based testing

AIM: To investigate dysfunctions in esophageal peristalsis and sensation in patients with Barrett’s esophagus following acid infusion using endoscopy-based testing.

METHODS: First, physiological saline was infused into the esophagus of five healthy subjects, at a rate of 10 mL/min for 10 min, followed by infusion of HCl. Esophageal contractions were analyzed to determine whether the contractions observed by endoscopy and ultrasonography corresponded to the esophageal peristaltic waves diagnosed by manometry. Next, using nasal endoscopy, esophageal sensations and contractions were investigated in patients with, as well as controls without, Barrett’s esophagus using the same infusion protocol.

RESULTS: All except one of the propulsive contractions identified endoscopically were recorded as secondary peristaltic waves by manometry. Patients with long segment Barrett’s esophagus (LSBE) tended to have a shorter lag time than the control group, although the difference did not reach statistical significance (88 ± 54 s vs 162 ± 150 s respectively, P = 0.14). Furthermore, patients with LSBE had significantly fewer secondary contractions following the infusion of both saline and HCl than did either the control group or patients with short segment Barrett’s esophagus (4.1 ± 1.2 vs 8.0 ± 2.8, P < 0.001 and 7.3 ± 3.2, P < 0.01, respectively, following saline infusion; 5.3 ± 1.2 vs 8.4 ± 2.4 and 8.1 ± 2.9 respectively, P < 0.01 for both, following infusion of HCl).

CONCLUSION: Using nasal endoscopy and a simple acid-perfusion study, we were able to demonstrate disorders in secondary peristalsis in patients with LSBE.

The dose of omeprazole required to achieve adequate intraesophageal acid suppression in patients with gastroesophageal junction specialized intestinal metaplasia and Barrett's esophagus

BACKGROUND

The mainstay of medical therapy for Barrett's esophagus is normalization of esophageal acid exposure with proton pump inhibitors (PPIs). However, the optimal dose and whether once daily or twice daily is required for acid suppression is unknown.

AIM

The purpose of this study was to assess whether adequate intra-esophageal acid suppression could be achieved with once daily versus twice daily omeprazole in patients with gastroesophageal specialized intestinal metaplasia (GEJSIM), short-segment (SSBE) and long-segment Barrett's esophagus (LSBE).

METHODS

Patients with GEJSIM and Barrett's esophagus underwent upper endoscopy with 48-h wireless pH capsule while on once daily 20 mg omeprazole for at least 1 week. If intra-esophageal acid was not adequately controlled, defined as pH value <4 for greater than 4.2 % of the time during the second 24-h period, omeprazole was increased to twice daily for 1 week and upper endoscopy with wireless pH capsule was repeated.

RESULTS

A total of 36 patients completed the study (10 patients had GEJSIM, 16 patients had SSBE, and 10 patients had LSBE). Normalization of intraesophageal pH was achieved in 28 patients (78 %) with once daily PPI and eight patients required twice daily PPI. There was no significant difference between the three groups in the proportion of patients requiring high dose PPI (GEJSIM 10 %, SSBE 25 %, LSBE 30 %, p = 0.526).

CONCLUSIONS

The majority of patients with Barrett's esophagus were controlled with once daily low dose PPI and only a minority required twice daily dosing, regardless of the length of Barrett's mucosa.

The daily response for proton pump inhibitor treatment in Japanese reflux esophagitis and non-erosive reflux disease

We investigated comparison according to reflux esophagitis and non-erosive reflux disease about “daily” symptom improvement for proton pump inhibitor treatment. We enrolled 57 reflux esophagitis and 90 non-erosive reflux disease patients. They took rabeprazole 10 mg/day for 28 days and completed “daily” in the Frequency Scale for the Symptoms of GERD from baseline until day 14, and after 28 days of treatment. The efficacy endpoint was the improvement rates in Frequency Scale for the Symptoms of GERD, based on baseline. Frequency Scale for the Symptoms of GERD was decreased in reflux esophagitis and non-erosive reflux disease (p<0.001) and was significantly lower in reflux esophagitis than in non-erosive reflux disease from the first day of treatment (p<0.05). Symptomatic improvement rates were also significantly higher in reflux esophagitis (50.3 ± 44.9%) than in non-erosive reflux disease (31.7 ± 43.2%) from the first day of treatment (p<0.0001). The symptomatic improvement rates in reflux esophagitis were significant increased from the second day of treatment until after 28 days of treatment (p = 0.0006), however, these in non-erosive reflux disease were significant increased from third days until after 28 days of treatment (p = 0.0002). In non-erosive reflux disease, the improvement of dysmotility symptom was particularly gradual as well as of reflux symptom, too. As for results of prediction of proton pump inhibitor response (completed symptom resolution) form early symptom improvement within 1 week, it was able to predict proton pump inhibitor response from the symptom improvement rate on 3 days in reflux esophagitis and on day 7 in non-erosive reflux disease. In conclusion, the prediction of the proton pump inhibitor response in non-erosive reflux disease was slow in comparison with reflux esophagitis. The cause was gradual improvement of dysmotility symptom.

Control of intra-oesophageal pH in patients with Barrett's oesophagus on omeprazole-sodium bicarbonate therapy

BACKGROUND

Approximately 30-40% of patients with Barrett's oesophagus (BE) patients manifest abnormal oesophageal pH profiles despite proton pump inhibitor (PPI) therapy.

AIM

To determine control of oesophageal reflux using Bravo pH monitoring in patients BE on omeprazole-sodium bicarbonate oral suspension powder (Ome-NaBic) 40 mg twice daily.

METHODS

Initial pH monitoring off PPI for 1 week was performed. All patients underwent repeat pH testing on Ome-NaBic administered before breakfast and at bedtime after 21-28 days of therapy depending upon the prior PPI therapy. The goal was to enroll 30 subjects, however, the trial was terminated prematurely when the sponsor lost financing due to a change in business strategy.

RESULTS

A total of 88 patients responded to the study invitation, 27 patients signed informed consent, and 21 patients underwent pH testing of PPI. A total of 15 patients completed the protocol (13 men, 2 women). Demographic information for patients completing at least one Bravo study included a mean (±s.d.) age 62 ± 9 years; body mass index 31 ± 8 kg/m(2) (range 23-48); mean BE length of 2.6 ± 2 cm; 9 (43%) patients with long segment BE. All (100%) patients demonstrated normalisation of supine pH on both days of Ome-NaBic therapy. One patient (6%) demonstrated abnormal upright reflux on the second day of monitoring on Ome-NaBic therapy; all the other patients demonstrated normal pH scores on therapy.

CONCLUSIONS

Administration of twice daily Ome-NaBic demonstrated control of nocturnal oesophageal reflux in 100% of patients with Barrett's oesophagus, and complete control of oesophageal pH during 97% of the 24-h recording periods.

Barrett's esophagus: proton pump inhibitors and chemoprevention II

The following on proton pump inhibitors (PPIs) and chemoprevention in relation to Barrett's esophagus includes commentaries on 48-h pH monitoring, pH-impedence, bile acid testing, dyspepsia, long/short segment Barrett's esophagus, nonerosive reflux disease (NERD), functional heartburn, dual-release delivery PPIs, immediate-release PPIs, long-term PPI use, prokinetic agents, obesity, baclofen, nocturnal acid breakthrough, nonsteroidal anti-inflammatory drugs (NSAIDs), and new PPIs.

Role of acid suppression in the development and progression of dysplasia in patients with Barrett's esophagus

Barrett's esophagus (BE) usually develops in patients with gastroesophageal reflux disease and therefore it has been suggested that esophageal acid exposure plays an import role in the initiation of BE and its progression towards esophageal adenocarcinoma (EAC). The mechanisms whereby acid exposure causes BE are not completely revealed and the potential role of esophageal acid exposure in carcinogenesis is unclear as well. Since acid exposure is thought to play an important role in the progression of BE, therapies aimed at preventing the development of EAC have primarily focused on pharmacological and surgical acid suppression. In clinical practice, acid suppression is effective in relieving reflux symptoms and decreases esophageal acid exposure in most patients. However, in some individuals, pathological acid exposure persists and these patients continue to be at risk for developing dysplasia or EAC. To date, published trials suggest that acid suppression is able to prevent the development and progression of dysplasia in patients with BE, but definite and compelling proof is still lacking. This article reviews the mechanisms of acid-induced carcinogenesis in BE and the role of acid suppression in the prevention of neoplastic progression.

Expression, localization and polymorphisms of the nuclear receptor PXR in Barrett's esophagus and esophageal adenocarcinoma

BACKGROUND

The continuous exposure of esophageal epithelium to refluxate may induce ectopic expression of bile-responsive genes and contribute to the development of Barrett's esophagus (BE) and esophageal adenocarcinoma. In normal physiology of the gut and liver, the nuclear receptor Pregnane × Receptor (PXR) is an important factor in the detoxification of xenobiotics and bile acid homeostasis. This study aimed to investigate the expression and genetic variation of PXR in reflux esophagitis (RE), Barrett's esophagus (BE) and esophageal adenocarcinoma.

METHODS

PXR mRNA levels and protein expression were determined in biopsies from patients with adenocarcinoma, BE, or RE, and healthy controls. Esophageal cell lines were stimulated with lithocholic acid and rifampicin. PXR polymorphisms 25385C/T, 7635A/G, and 8055C/T were genotyped in 249 BE patients, 233 RE patients, and 201 controls matched for age and gender.

RESULTS

PXR mRNA levels were significantly higher in adenocarcinoma tissue and columnar Barrett's epithelium, compared to squamous epithelium of these BE patients (P<0.001), and RE patients (P=0.003). Immunohistochemical staining of PXR showed predominantly cytoplasmic expression in BE tissue, whereas nuclear expression was found in adenocarcinoma tissue. In cell lines, stimulation with lithocholic acid did not increase PXR mRNA levels, but did induce nuclear translocation of PXR protein. Genotyping of the PXR 7635A/G polymorphism revealed that the G allele was significantly more prevalent in BE than in RE or controls (P=0.037).

CONCLUSIONS

PXR expresses in BE and adenocarcinoma tissue, and showed nuclear localization in adenocarcinoma tissue. Upon stimulation with lithocholic acid, PXR translocates to the nuclei of OE19 adenocarcinoma cells. Together with the observed association of a PXR polymorphism and BE, this data implies that PXR may have a function in prediction and treatment of esophageal disease.

The effects of high-dose esomeprazole on gastric and oesophageal acid exposure and molecular markers in Barrett's oesophagus

BACKGROUND

Acid reflux is often difficult to control medically.

AIM

To assess the effect of 40 mg twice daily esomeprazole (high-dose) on gastric and oesophageal pH and symptoms, and biomarkers relevant to adenocarcinoma, in patients with Barrett's oesophagus (BO).

METHODS

Eighteen patients, treated with proton pump inhibitors as prescribed by their treating doctor, had their therapy increased to high-dose esomeprazole for 6 months.

RESULTS

At entry into the study, 9/18 patients had excessive 24-h oesophageal acid exposure, and gastric pH remained <4 for >16 h in 8/18. With high-dose esomeprazole, excessive acid exposure occurred in 2/18 patients, and gastric pH <4 was decreased from 38% of overall recording time and 53% of the nocturnal period to 15% and 17%, respectively (P < 0.001). There was a reduction in self-assessed symptoms of heartburn (P = 0.0005) and regurgitation (P < 0.0001), and inflammation and proliferation in the Barrett's mucosa. There was no significant change in p53, MGMT or COX-2 expression, or in aberrant DNA methylation.

CONCLUSIONS

High-dose esomeprazole achieved higher levels of gastric acid suppression and control of oesophageal acid reflux and symptoms, with significant decreases in inflammation and epithelial proliferation. There was no reversal of aberrant DNA methylation.

The effect of argon plasma coagulation ablation on esophageal motility and chemoreceptor sensitivity in Barrett's esophagus patients

Patients with Barrett's esophagus usually demonstrate impaired esophageal motility, which affects acid clearance, together with reduced chemo-receptor sensitivity and symptom severity. Ablative endoscopic techniques are now used to eliminate Barrett's cells. The hypothesis for this study was that ablation with argon plasma coagulation (APC) may affect esophageal sensitivity and motility in patients with Barrett's esophagus, and the aim of this study was to assess differences in these parameters before and after APC treatment. Twenty patients with Barrett's esophagus were investigated before and after APC therapy. After standard pull through manometry, water bolus aliquots were given to assess primary peristalsis and rapid water and air bolus injections to assess secondary peristalsis. Sensitivity studies were carried out using weak solutions of either hydrochloric acid or sodium hydroxide, together with saline washouts. Onset time for typical symptoms (t), sensory intensity rating (I), and a sensory score (SS) = (t) x (I)/100 was observed. There were no significant differences in the lower esophageal sphincter pressures (13.6 mm Hg versus 12.6 mm Hg, P= 0.8) and successful test swallows (3 mm Hg versus 5 mm Hg, P= 0.5) before and after treatment, but there was a trend for secondary peristalsis to improve (air bolus 0 versus 2, P= 0.05, water bolus 0 versus 1, P= 0.07). Sensitivity studies showed a smaller sensitivity intensity rating to both acid (61 versus 31, P= 0.02) and alkaline (91 versus 64, P= 0.03) after treatment. In conclusion, we have shown no substantive changes in esophageal motility after ablation of Barrett's esophagus cells, but have demonstrated reduced sensitivity to reflux type solutions.

The role of weakly acidic reflux in proton pump inhibitor failure, has dust settled?

Patients that do not respond satisfactorily to standard proton pump inhibitor (PPI) treatment have become the most common presentation of gastro-esophageal reflux disease (GERD) in third referral gastrointestinal practices. The causes of refractory GERD include lack of compliance with treatment, residual acid reflux and weakly acidic reflux, esophageal hypersensitivity and persistent symptoms not associated with reflux. A role for weakly acidic reflux in symptom generation has been proposed since the availability of impedance-pH monitoring. The possible mechanisms by which persistent weakly acidic reflux might contribute to persistent symptoms in patients under PPI treatment may include esophageal distension by increased reflux volume, persistent impaired mucosal integrity (ie, dilation of intercellular spaces) and/or esophageal hypersensitivity to weakly acidic reflux events. To establish a definite role of weakly acidic reflux in refractory GERD, outcome studies targeting this type of reflux are still lacking. Treatment strategies to reduce the number or effect of weakly acidic reflux could involve drugs that decrease transient lower esophageal sphincter relaxations (ie, baclofen or similar), improve oesophageal mucosa resistance or visceral pain modulators. Finally, anti-reflux surgery can be considered, only if a clear symptom-weakly acidic reflux association was demonstrated.

The extent and determinants of prescribing and adherence with acid-reducing medications: a national claims database study

OBJECTIVES

No community-based, large-scale studies have examined the extent of prescribing acid-reducing medications or adherence and persistence to these medication regimens.

METHODS

We conducted a retrospective cohort study of patients with Barrett's esophagus (BE) and gastroesophageal reflux disease (GERD) without BE, diagnosed between 2000 and 2005, who had undergone an upper endoscopy within 1 year through a managed care plan in the United States. We identified filled prescriptions for oral proton pump inhibitors (PPIs) or histamine-2 receptor antagonists (H2RAs) within 365 days after the index date of BE or GERD, and several measures of adherence (medication-ownership ratio (MOR)) and persistence (length of therapy, fill-refill ratio, discontinuation rate) for PPI treatment.

RESULTS

We identified 10,159 patients with BE and 48,965 GERD patients with no BE. The mean duration of filled PPI prescriptions accounted for only 30.2% of the available year after the index date, whereas that of either PPI or H2RA prescriptions accounted for only 31.7%. PPI prescriptions were filled by 66.6 and 60.4% of patients with and without BE, respectively. These proportions declined significantly between 2000 and 2005. For those with at least one prescription, the median duration of therapy was 241 days for PPIs and 159 for H2RAs. Both groups had low MOR and length of treatment and high discontinuation rates; however, adherence and persistence were significantly higher in BE than in non-BE patients, and significantly lower in 2005 than in 2000.

CONCLUSIONS

The use of prescription PPIs or H2RAs, as well as adherence and persistence with these medications, is lower than expected. The absence of BE and more recent diagnosis are associated with even lower prescription rates.

Esophageal acid exposure on proton pump inhibitors in unselected asymptomatic gastroesophageal reflux disease patients

BACKGROUND AND AIM

Efficacy of proton pump inhibitors (PPIs) on symptoms of gastroesophageal reflux (GER) is supposed to result from normalization of esophageal acid exposure; however, recent data in selected severe patients have challenged this concept. The aim of the study was to investigate 24-hour esophagogastric pH in unselected patients with GER disease in symptomatic remission during PPIs.

METHODS

Thirty of the 31 consecutive patients with heartburn enrolled achieved adequate symptom control (<or=1 heartburn episode/wk) on PPIs o.d. (n=22) or b.d. (n=8); 3 refused pH monitoring, thus 27 tracings were analyzed.

RESULTS

Medians (Interquartile Range); Intragastric tracings showed a wide range of inhibition of acid secretion, 61.2% (49.7% to 80.2%) time at pH>4, nocturnal acid breakthrough being shorter (P=0.03) on PPIs b.d. compared with PPIs o.d., 125 minutes (90 to 247) versus 253 minutes (210 to 340). Esophageal acid exposure was 3.3% (1.4% to 7.9%) time at pH<4, 9 patients having increased exposure (ie, >5.5%), 7 of whom on PPIs o.d. Patients with increased acid GER on PPIs had a higher prevalence of esophagitis (67% vs. 22%, P<0.05) and hiatus hernia (78% vs. 39%, P<0.1) at endoscopy off PPIs.

CONCLUSIONS

One third of unselected patients with GER disease asymptomatic on PPIs have an increased esophageal acid exposure, especially if their PPI is administered o.d.

Barrett's esophagus: pathogenesis, treatment, and prevention

Esophageal adenocarcinoma is the most common type of esophageal cancer seen in the United States and Western Europe. Barrett's esophagus (BE) is a well-known risk factor for esophageal adenocarcinoma and is believed to be found in 6% to 12% of patients undergoing endoscopy for gastroesophageal reflux disease and in more than 1% of all patients undergoing endoscopy. This article focuses on the pathogenesis, treatment, and prevention of BE.

The use of acid-decreasing medication in veteran patients with gastro-oesophageal reflux disorder with and without Barrett's oesophagus

AIM

To examine use of acid-decreasing medications, especially proton pump inhibitors (PPIs), in patients with gastro-oesophageal reflux disorder (GERD) with and without Barrett's oesophagus (BO) in a large-scale study.

METHODS

We conducted a retrospective cohort study of patients with newly diagnosed BO (ICD-9 code 5302) and patients with GERD and no BO (ICD-9 53081, 5301) in Department of Veterans Affairs (VA) databases. Filled prescriptions for oral PPI and histamine2-receptor antagonists (H2RA) were identified in the VA Pharmacy Benefit Management database during 365 days following diagnosis. Groups with or without PPI or H2RA were compared in unadjusted and adjusted regression analyses. Chart review was used to validate diagnoses in a subset of patients with and without BO.

RESULTS

We evaluated 7732 patients with BO and 13 457 with GERD and no BO diagnosed between 1/2000 and 12/2002. At least one PPI prescription was filled during the first year following diagnosis in 91.5% of BO and 61.4% of non-BO patients (P < 0.0001), and one H2RA in 31.7% of BO and 59.4% of non-BO patients (P < 0.0001), respectively. However, 6.1% of BO patients were prescribed neither. Median duration for PPI filled prescriptions was twice as long for BO (221.7 vs. 106.9 days) compared with non-BO patients. The ratio of PPI or H2RA filled prescription days to available follow-up days among BO subjects was 0.66 (122.8 days were not covered with prescription for either), and 0.55 in GERD patients with no BO (165.0 days on neither).

CONCLUSIONS

Veterans Affairs patients with BO are 50% more likely to be prescribed a PPI than patients with GERD and no BO. However, on average, PPI prescriptions cover only 60% of follow-up time for BO patients.

Time esophageal pH < 4 overestimates the prevalence of pathologic esophageal reflux in subjects with gastroesophageal reflux disease treated with proton pump inhibitors

Background

A Stanford University study reported that in asymptomatic GERD patients who were being treated with a proton pump inhibitor (PPI), 50% had pathologic esophageal acid exposure.

Aim

We considered the possibility that the high prevalence of pathologic esophageal reflux might simply have resulted from calculating acidity as time pH < 4.

Methods

We calculated integrated acidity and time pH < 4 from the 49 recordings of 24-hour gastric and esophageal pH from the Stanford study as well as from another study of 57 GERD subjects, 26 of whom were treated for 8 days with 20 mg omeprazole or 20 mg rabeprazole in a 2-way crossover fashion.

Results

The prevalence of pathologic 24-hour esophageal reflux in both studies was significantly higher when measured as time pH < 4 than when measured as integrated acidity. This difference was entirely attributable to a difference between the two measures during the nocturnal period. Nocturnal gastric acid breakthrough was not a useful predictor of pathologic nocturnal esophageal reflux.

Conclusion

In GERD subjects treated with a PPI, measuring time esophageal pH < 4 will significantly overestimate the prevalence of pathologic esophageal acid exposure over 24 hours and during the nocturnal period.

Treatment of Barrett's esophagus with early neoplasia: a comparison of endoscopic therapy and esophagectomy

BACKGROUND

Endoscopic therapies for early neoplasia in Barrett's esophagus may be a viable alternative to esophagectomy.

OBJECTIVE

Our purpose was to compare endoscopic therapy and esophagectomy.

DESIGN

Retrospective review from a single institution.

SETTING

A medium-sized tertiary referral center.

PATIENTS AND INTERVENTIONS

All patients with Barrett's esophagus and dysplasia or intramucosal carcinoma treated by photodynamic therapy (PDT), EMR, or argon plasma coagulation (APC) or esophagectomy with curative intent from May 1998 until November 2005.

MAIN OUTCOME MEASUREMENTS

Survival, progression to cancer, eradication of dysplasia and Barrett's esophagus, major and minor complications, and costs were compared.

RESULTS

Sixty-two patients who underwent endoscopic therapy (2 APC alone, 18 EMR + APC, 20 PDT + APC, and 22 EMR + PDT + APC) and 32 patients who underwent esophagectomy met the inclusion criteria. The 30-day mortality rate included 1 patient in the endotherapy group (2%) and none in the surgical group (P = .49). No deaths from esophageal cancer occurred in either group. Cancer developed in 6% of endotherapy patients and in none in the surgical cohort (P < .05). Major and minor complications occurred in 8% and 31% of endotherapy patients, respectively, and 13% and 63% of surgery patients (P = .50, P < .001). Median cost to date was $40,079 for endotherapy and $66,060 for esophagectomy (P < .001).

LIMITATIONS

Retrospective study, relatively short follow-up, small numbers.

CONCLUSIONS

Both endotherapy and esophagectomy can effectively treat high-grade dysplasia and intramucosal carcinoma associated with Barrett's esophagus. Endotherapy is associated with a higher risk of tumor progression, although this is uncommon. Esophagectomy incurs higher initial costs and results in more frequent minor complications but is usually curative.

Refractory gastrooesophageal reflux disease

The introduction of proton pump inhibitors (PPIs) has facilitated the treatment of gastrooesophageal reflux disease (GORD) enormously; however, treatment of GORD still fails in a small proportion of patients. This small proportion of therapy-resistant patients encompasses a substantial part of the working load of physicians and has become a common clinical problem. A strong variability in acid-suppressive effect of PPI treatment exists depending on compliance, Helicobacter pylori status and genotype. Nocturnal acid breakthrough does not seem to be a major determinant of refractory GORD. Recent data, however, show that PPI-refractory GORD can result from nonacid reflux episodes. It is wise to reconsider the diagnosis of GORD in patients who are PPI-refractory. Most patients in whom a PPI is not effective do not have GORD, instead they suffer from other disorders such as functional dyspepsia. If after a thorough history is taken the suspicion of GORD is still high, the next step would be to perform upper endoscopy and reflux monitoring. In case patients truly have PPI-refractory GORD, therapy can be aimed at oesophageal hypersensitivity or a surgical solution can be sought.

Proton-pump inhibitor therapy in patients with gastro-oesophageal reflux disease: putative mechanisms of failure

Proton-pump inhibitor (PPI) failure in gastro-oesophageal reflux disease (GORD) patients has become the main reason for referral of these patients to gastroenterology specialists. It is estimated that 30% of GORD patients requiring a PPI once daily will experience treatment failure. Patients with non-erosive reflux disease are the most common GORD-related group in which once-daily PPI therapy fails. Various mechanisms have been suggested to underlie PPI failure in GORD patients. The most pertinent include weakly acidic reflux, duodenogastro-oesophageal reflux, visceral hyperalgesia, delayed gastric emptying, psychological co-morbidity and concomitant functional bowel disorders, as well as others. Because of the importance of PPI failure as a target for future drug development, further understanding of the most relevant underlying mechanisms is needed.

Comparisons of the distribution of oesophageal acid exposure throughout the sleep period among the different gastro-oesophageal reflux disease groups

BACKGROUND

Nocturnal gastro-oesophageal reflux diseases (GERD) can lead to oesophageal mucosal injury and extra-oesophageal complications.

AIM

To compare distribution of oesophageal acid exposure during sleep time among patients with non-erosive reflux disease and abnormal pH test (NERD-positive), erosive oesophagitis (EO) and Barrett's oesophagus (BO).

METHODS

Patients underwent endoscopy followed by 24-h oesophageal pH testing. Oesophageal acid exposure was assessed every 2 h of the sleep period (0-2, 2-4, 4-6 and 6-8 h). Each period of 2 h was evaluated for acid reflux parameters. All groups were matched by age, time from last meal and duration of sleep time.

RESULTS

Thirty-eight patients were enrolled (NERD-positive, 16; EO, 1.4; and BO, 8). All GERD groups demonstrated higher oesophageal acid exposure in the first vs. second half of the sleep period as determined by percent time pH <4 (BO: 34.7 vs.11.6, EO: 13.5 vs. 6.9, NERD-positive: 8.8 vs. 2.5, all P < 0.01). In general, patients with BO had a significantly higher distribution of oesophageal acid exposure than those with NERD-positive and EO.

CONCLUSIONS

Oesophageal acid exposure generally declines throughout the sleep period regardless of GERD group, but BO patients demonstrated the greatest decline during the sleep period.

Factors influencing the shift of patients from one proton pump inhibitor to another: the effect of direct-to-consumer advertising

BACKGROUND

Switching from one proton pump inhibitor (PPI) to another is common, and may be related to factors other than efficacy and tolerability.

OBJECTIVES

The purposes of this study were to describe the incidence of therapeutic switching among PPI users, quantify direct ambulatory medical costs of switching, and characterize the relationship between product switching and variables hypothesized to influence a switch (eg, direct-to-consumer [DTC] advertising, structure of insurance coverage, disease diagnosis).

METHODS

This was a retrospective cohort study of health plans using 1998 data. The subjects were employees and dependents with employer-sponsored health insurance contributing to the Medstat Market-Scan administrative dataset. Using a commercially available database to quantify DTC advertising by marketing area, market-specific expenditures were matched to eligible subjects. Among PPI users, we identified those who switched from one product to another (switchers) and compared their utilization and spending with nonswitchers. We then evaluated the relationship between drug use and variables hypothesized to affect switching: DTC advertising, insurance characteristics, patient diagnosis, diagnostic procedures, comorbidities, age, and sex.

RESULTS

The analysis used data for 396,500 individuals from 47 unique markets that were geographically well distributed, with population density similar to that of the United States overall. The sample was also comparable with US census estimates for age and sex among working adults and their dependents. Only 620 (6.3%) of PPI users switched products during the 1998 calendar year. Annual diagnostic and drug costs were >US $400 higher for switchers than nonswitchers. Subjects in areas with high levels of DTC advertising were 43% more likely to switch from lansoprazole to omeprazole than those in the low-expenditure areas. Additionally, patients paying prescription drug copayments >US $5 were 12% less likely to switch from lansoprazole to omeprazole than patients paying lower copayments.

CONCLUSIONS

In these privately insured patients using PPIs, product switching was associated with increased treatment costs. DTC advertising and patient cost-sharing were important predictors of product switching.

Changes in esophageal motility after porfimer sodium photodynamic therapy for Barrett's dysplasia and mucosal carcinoma

Esophageal dysmotility is common in patients with Barrett's esophagus. Previously we have reported deterioration of esophageal motility after photodynamic therapy (PDT) in a heterogeneous group of patients with esophageal carcinoma. This prospective study in consecutive patients describes changes in motility noted after endoscopic ablation. Forty-seven patients referred to our institution for endoscopic ablation for Barrett's high grade dysplasia or mucosal carcinoma between August 2001 and May 2003 were prospectively evaluated with esophageal manometry before and after porfimer sodium PDT. Six patients did not complete the study. Manometry results were classified as normal, diffuse esophageal spasm, ineffective esophageal motility, or aperistalsis. Abnormal esophageal motility was found in 14 of 47 (30%) patients at study entry ([diffuse esophageal spasm] DES-3, [ineffective esophageal motility] IEM-7, Aperistalsis-4). After PDT, 11 of 41 patients with paired studies experienced a change in manometric diagnosis. Three patients had an improvement in motility, seven a worsening and one changed diagnosis, but did not particularly worsen or improve. No patient developed new aperistalsis. Therefore, abnormal motility was present in 19 of 41 (46%) patients after PDT (DES-2, IEM-14, Aperistalsis-3). There was a statistically significant (P = 0.016) relationship with longer segment Barrett's esophagus and deterioration of function. Baseline abnormalities in motility can occur in patients with Barrett's high-grade dysplasia or mucosal carcinoma. Changes in esophageal function also may occur following photodynamic therapy, but usually are not clinically significant. Worsening in function was more likely to occur in patients with longer segment Barrett's esophagus.

Gastric and esophageal pH in patients with Barrett's esophagus treated with three esomeprazole dosages: a randomized, double-blind, crossover trial

BACKGROUND

It has been suggested that patients with Barrett's esophagus (BE) are unusually resistant to the antisecretory effects of proton pump inhibitors (PPIs).

OBJECTIVES

To compare intragastric and intraesophageal acidity in patients with BE receiving esomeprazole 40 mg three times daily (t.i.d.), esomeprazole 40 mg twice daily (b.i.d.), and esomeprazole 20 mg t.i.d.

METHODS

In this randomized, double-blind, three-way crossover study, patients with long-segment BE received each of the three esomeprazole dosages for 5 days separated by 10-14-day washout periods. Intragastric and intraesophageal pHs were measured for 24 h on day 5.

RESULTS

Among 31 patients with evaluable pH data, intragastric pH was >4.0 for 88.4%, 81.4%, and 80.4% of day 5 after treatment with esomeprazole 40 mg t.i.d., 40 mg b.i.d., and 20 mg t.i.d., respectively. Esomeprazole 40 mg t.i.d. was significantly more effective than the other dosages (p < 0.01). Intraesophageal pH was <4.0 for mean values of <5% of the monitoring period with all the three dosing regimens, but esophageal pH remained <4.0 for >5% of the time in 16%, 23%, and 19% of patients receiving esomeprazole 40 mg t.i.d., 40 mg b.i.d., and 20 mg t.i.d., respectively. All dosages were well tolerated.

CONCLUSIONS

All the three esomeprazole dosages significantly decreased intragastric acidity and reduced esophageal acid exposure to mean normal values in the total group of patients with BE. However, abnormal esophageal acid exposure continued in 16-23% of patients despite the significant decrease in gastric acidity. These results suggest that the apparent "PPI resistance" described in patients with BE may be caused by their profound reflux diathesis rather than by gastric resistance to the antisecretory effects of PPIs.

N/A

N/A

Review article: intragastric and oesophageal pH monitoring in patients with gastro-oesophageal reflux disease

Treatment of gastro-oesophageal reflux disease with acid suppressive therapy is based on the principle that effective control of intragastric pH (a marker of acid control) leads to healing of erosive oesophagitis and relief of gastro-oesophageal reflux disease-associated symptoms. Most patients with gastro-oesophageal reflux disease can be managed successfully with current antisecretory therapy. In difficult-to-treat patients, oesophageal pH monitoring is a useful technique to assess pH control and to investigate the association of reflux with refractory symptoms. Intragastric pH monitoring allows direct assessment of acid suppression achieved with an agent, and is the most useful for head-to-head comparisons of antisecretory therapies, evaluating variability in individual gastric pH response, assessing dose timing and food effect, and determining alternate dosing strategies; as such, it is useful in the research laboratory, and may be useful clinically to guide clinicians in dose titration and in evaluating the effect of switching agents. This article reviews these and other uses of these tests in an effort to explore the question of how to optimally use oesophageal pH monitoring and gastric pH monitoring in patient management.

Barrett's oesophagus is characterized by a predominantly humoral inflammatory response

Barrett's oesophagus (BO) is thought to be an intermediate step in the progression from reflux oesophagitis (RO) to oesophageal adenocarcinoma. Premalignant conditions that develop in the presence of chronic inflammation are often associated with the development of a more pronounced humoral immune response during progression of the disease. The aim of this study was to determine whether BO is also associated with a more pronounced humoral immune response when compared to RO. Immunohistochemical studies were performed to quantify the mean numbers of Th2 effector cells (plasma cells and mast cells) and Th1 effector cells (macrophages and CD8(+) T cells) to detect the antibody classes produced by plasma cells (IgA, IgG, IgM or IgE) and to determine the presence of isolated lymph follicles [segregated B and T cell areas, follicular dendritic cells (CD23) and expression of CXCL13] in 124 oesophageal biopsies from 20 patients with BO and 20 patients with RO. The proportion of Th2 effector cells was higher in BO than in RO, mainly due to higher numbers of plasma cells and mast cells in BO (p < 0.001). Most plasma cells in BO and RO expressed IgG, but several IgE(+) plasma cells were detected in BO: these were rare in RO. In line with this, isolated lymph follicles were observed in 4/20 (20%) patients with BO, but not in RO. We therefore conclude that the inflammatory response is skewed towards a more pronounced humoral immune response when RO progresses to BO. It may be that this shift, which is similar to that found in other chronic inflammatory conditions, contributes to an increased cancer risk in BO.

Review article: putting immediate-release proton-pump inhibitors into clinical practice--improving nocturnal acid control and avoiding the possible complications of excessive acid exposure

Nocturnal gastro-oesphageal reflux is an under-appreciated clinical challenge. This condition may cause symptoms such as nocturnal heartburn, or it may be asymptomatic. In addition, patients may experience sleep disturbances that can potentially lead to complications such as erosive oesophagitis and Barrett's oesophagus, and may be a risk factor for development of oesophageal adenocarcinoma. Delayed-release proton-pump inhibitors (PPIs) have traditionally been effective in treating both daytime and night-time reflux symptoms, but are limited in control of nocturnal acidity by their pharmacodynamic characteristics. This narrative review addresses the prevalence, impact and pharmacologic approaches used to control nocturnal acidity. Methods to optimize nocturnal acid control include careful attention to dosing schedule, using higher doses of PPIs, adding an histamine H2-receptor antagonist at bedtime to once or twice daily delayed-release PPI, or using immediate-release omeprazole (Zegerid powder for oral suspension; Santarus, Inc., San Diego, CA, USA). This new formulation appears to provide sustained control of intragastric pH at steady state, and when dosed at bedtime, and may be effective in improving control of nocturnal pH and treating night-time GERD.

Lack of predictors of normalization of oesophageal acid exposure in Barrett's oesophagus

BACKGROUND

Barrett's oesophagus patients may continue to have abnormal oesophageal acid exposure on proton pump inhibitor therapy. The effect of factors such as Barrett's oesophagus length, hiatal hernia size and Helicobacter pylori infection on intra-oesophageal pH in Barrett's oesophagus patients has not been adequately studied.

AIM

To evaluate oesophageal acid exposure in a large Barrett's oesophagus population on b.d. proton pump inhibitor therapy and determine clinical factors predicting normalization of intra-oesophageal pH on therapy.

METHODS

Barrett's oesophagus patients were studied using 24 h pH monitoring to evaluate intra-oesophageal acid suppression on b.d. dosing of rabeprazole.

RESULTS

Forty-six Barrett's oesophagus patients completed the study. Median total percentage time pH < 4 was 1.05% (range: 0-29.9%) in the entire group and respective values for upright and supine percentage time pH < 4 were 1.15% and 0%. However, 34 of the Barrett's oesophagus patients (73.9%) had a normal pH study (median total percentage time pH < 4: 0.2%) and 12 patients (26.1%) had an abnormal result (median total percentage time pH < 4: 9.3%). There were no significant differences between patients with a normal and abnormal 24 h pH result with respect to age, Barrett's oesophagus length, hiatal hernia size and presence of H. pylori infection.

CONCLUSIONS

Approximately 25% of Barrett's oesophagus patients continue to have abnormal total intra-oesophageal pH profiles despite b.d. proton pump inhibitor therapy. Factors such as age, Barrett's oesophagus length and hiatal hernia size cannot be used to predict persistent abnormal intra-oesophageal pH on proton pump inhibitor.

Systematic review: proton-pump inhibitor failure in gastro-oesophageal reflux disease--where next?

Proton-pump inhibitor failure has become a common clinical dilemma in gastrointestinal clinics and has been increasingly encountered at the primary care level as well. Underlying mechanisms are diverse and may overlap. Most patients who have proton-pump inhibitor failure are likely to originate from the non-erosive reflux disease phenotype. Currently, available diagnostic modalities provide limited clues to the exact underlying cause. Treatment relies primarily on escalating dosing of proton-pump inhibitors. However, new insights into the pathophysiology of proton-pump inhibitor failure are likely to provide alternative therapeutic options.

Catheter-based pH monitoring: use in evaluation of gastroesophageal reflux disease symptoms (on and off therapy)

Tube-based ambulatory pH testing has rapidly evolved in the past 3 decades to become the standard by which other diagnostic approaches to gastroesophageal reflux disease are judged. Acid exposure 5 cm above the manometrically determined lower esophageal sphincter is the standard for documentation of pathologic acid exposure of the distal esophagus. Proximal esophageal or hypopharyngeal monitoring is an evolving technique that may shed light on patients with supraesophageal symptoms. The ability to simultaneously monitor esophageal and gastric acidity (usually in patients with persistent symptoms despite therapy) is another advantage of this technique. Whether the new system that allows simultaneous pH and impedance monitoring and the system that uses an implantable tubeless monitoring capsule will supplant this older but well-established technology remains to be determined.

Randomized trial of argon plasma coagulation vs. multipolar electrocoagulation for ablation of Barrett's esophagus

BACKGROUND

Endoscopic ablation of Barrett's esophagus has been described in which various thermocoagulation modalities are used in combination with a high dose of a proton pump inhibitor. No randomized comparison of ablation strategies has been published.

METHODS

Referred patients were screened to identify those with Barrett's esophagus 2 to 7 cm in length, without high-grade dysplasia or cancer. Included patients received pantoprazole (40 mg twice a day), followed by randomization to treatment with argon plasma coagulation (APC) or multipolar electrocoagulation (MPEC). The primary outcome measure was the number of treatment sessions required for endoscopic ablation.

RESULTS

Of 235 patients screened, 52 were randomized. The mean length of Barrett's esophagus was 3.1 cm in the MPEC group vs. 4.0 cm in the APC group (p = 0.03). Otherwise, the treatment groups were similar with regard to baseline characteristics. The mean number of treatment sessions required for endoscopic ablation was 2.9 for MPEC vs. 3.8 for APC (p = 0.04) in an intention-to-treat analysis (p = 0.249, after adjustment for the difference in length of Barrett's esophagus). The proportion of patients in which ablation was endoscopically achieved proximal to the gastroesophageal junction was 88% for the MPEC group vs. 81% for the APC group (p = 0.68) and histologically achieved in 81% for MPEC vs. 65% for APC (p = 0.21). The mean time required for the first treatment session was 6 minutes with MPEC vs. 10 minutes with APC (p = 0.01) in per protocol analysis. There was no serious adverse event, but transient moderate to severe upper-GI symptoms occurred after MPEC in 8% vs. 13% after APC (p = 0.64). Conclusions Although there were no statistically significant differences, ablation of Barrett's esophagus with pantoprazole and MPEC required numerically fewer treatment sessions, and endoscopic and histologic ablation was achieved in a greater proportion of patients compared with treatment with pantoprazole and APC.

Gastrin-induced cyclooxygenase-2 expression in Barrett's carcinogenesis

PURPOSE

Cyclooxygenase (COX)-2 has been causally implicated in carcinogenesis. The evidence for increased COX-2 in the malignant progression of Barrett's esophagus is contradictory. We hypothesize that COX-2 expression may be causally affected by the gastrin status via the cholecystokinin 2 (CCK(2)) receptor.

EXPERIMENTAL DESIGN

COX-2 and prostaglandin E(2) expression were evaluated by Western blotting and enzyme-linked immune assay in samples of squamous esophagus, Barrett's esophagus with varying degrees of dysplasia to adenocarcinoma, and normal duodenum. Differentiation status was evaluated by histopathology and villin expression. A longitudinal case-control study compared COX-2 in patients who progressed to adenocarcinoma with nonprogressors matched for age and length of follow-up. Messenger RNA levels of gastrin and CCK(2) receptor in biopsies and cell lines were evaluated by reverse transcription-PCR, and in vitro gastrin stimulation was conducted with and without inhibitors for CCK(2) (YM022) and COX-2 (NS-398). Cell proliferation was evaluated using minichromosome maintenance protein 2 (Mcm2) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays.

RESULTS

COX-2 expression is significantly increased in Barrett's esophagus before dysplasia development. Expression is highly variable within Barrett's dysplasia and adenocarcinoma samples independent of differentiation status. In a longitudinal case-control study, the expression levels within patients increased over time, regardless of the degree of malignant progression. Biopsies from nondysplastic Barrett's esophagus expressed increased gastrin mRNA levels compared with other biopsies. Gastrin significantly induced COX-2, prostaglandin E(2), and cell proliferation in biopsies and cell lines. Gastrin-induced proliferation can be inhibited by YM022 and NS-398.

CONCLUSIONS

COX-2 is up-regulated early in the Barrett's metaplasia sequence. During carcinogenesis, gastrin is a significant determinant of COX-2 activity levels via the CCK(2) receptor.

Updated guidelines for the diagnosis and treatment of gastroesophageal reflux disease

Guidelines for the diagnosis and treatment of gastroesophageal reflux disease (GERD) were published in 1995 and updated in 1999. These and other guidelines undergo periodic review. Advances continue to be made in the area of GERD, leading us to review and revise previous guideline statements. GERD is defined as symptoms or mucosal damage produced by the abnormal reflux of gastric contents into the esophagus. These guidelines were developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee, and approved by the Board of Trustees. Diagnostic guidelines address empiric therapy and the use of endoscopy, ambulatory reflux monitoring, and esophageal manometry in GERD. Treatment guidelines address the role of lifestyle changes, patient directed (OTC) therapy, acid suppression, promotility therapy, maintenance therapy, antireflux surgery, and endoscopic therapy in GERD. Finally, there is a discussion of the rare patient with refractory GERD and a list of areas in need of additional study.

Review article: management of oesophageal adenocarcinoma -- control of acid, bile and inflammation in intervention strategies for Barrett's oesophagus

Oesophagitis is associated with Barrett's metaplasia in about 10% of individuals. The UK has one of the highest world-wide prevalences of Barrett's metaplasia, with 1% of adults having the condition, resulting in an incidence of oesophageal adenocarcinoma two to three times that seen in either Europe or North America. In addition, the conversion rate to cancer in individuals with Barrett's metaplasia in UK surveillance programmes is twice that observed in the USA (0.96% per year vs. 0.4% per year), lending further support to the notion that the UK is a high-risk region. The evidence base on what can be achieved with medical therapy to reduce the risk of dysplasia or the development of adenocarcinoma needs to be strengthened with data from randomized controlled trials, as existing data have many limitations. Patients with Barrett's metaplasia respond variably to proton pump inhibitor therapy (even high-dose therapy 'normalizes' acid reflux in only 85% of cases), and symptom control is a poor determinant of the adequacy of suppression of acid reflux. Gastro-oesophageal reflux is implicated in the pathogenesis of Barrett's metaplasia, and ex vivo and in vitro evidence suggests that its attenuation reverses proliferation and biological variables over days, and perhaps the metaplastic histology to a degree over years. The effect of proton pump inhibitor therapy on cancer risk in the long term is essentially unknown. Acid suppressant therapy or anti-reflux surgery on its own does not result in the complete regression of the metaplastic epithelium. Bile acids, present especially frequently in the refluxate of Barrett's oesophagus patients, are also likely to influence the development and persistence of metaplasia. Barrett's metaplasia is replaced by a squamous epithelium when acid reflux is well controlled and the epithelium is physically destroyed by ablation with argon plasma coagulation or photodynamic therapy. These modalities are invasive and are not likely to be useful in the routine management of patients with Barrett's oesophagus without dysplasia or cancer. Why metaplasia does not fully regress once external initiating stimuli are removed is a mystery. There is some evidence to implicate a variety of molecules, including cyclo-oxygenase-2, tumour necrosis factor-alpha, beta-catenin nuclear translocation and mitogen-activated protein kinase signalling, because they are expressed preferentially in metaplastic rather than normal or inflamed squamous oesophageal mucosa. The use of non-steroidal anti-inflammatory drugs, including aspirin, is associated with a decreased incidence of oesophageal adenocarcinoma. There is therefore a great need for randomized controlled trials to assess the outcomes of such chemopreventive therapy in patients with Barrett's metaplasia.

Oesophageal and gastric pH profiles in patients with gastro-oesophageal reflux disease and Barrett's oesophagus treated with proton pump inhibitors

BACKGROUND

Acid plays a significant role in the development of gastro-oesophageal reflux symptoms and tissue damage. It is generally assumed that acid suppressive therapy with proton pump inhibitors improves or eliminates symptoms of gastro-oesophageal reflux disease by normalizing intra-oesophageal pH. However, the degree of acid suppression induced by proton pump inhibitor therapy in patients with gastro-oesophageal reflux disease and/or Barrett's oesophagus has not been adequately studied.

AIM

To assess the efficacy of proton pump inhibitors in normalizing intra-oesophageal and intra-gastric pH in patients with gastro-oesophageal reflux disease with and without Barrett's oesophagus who have been rendered symptom-free by acid-suppressive therapy.

METHODS

Patients with gastro-oesophageal reflux disease and Barrett's oesophagus were prospectively evaluated by dual sensor 24-h pH monitoring while receiving proton pump inhibitor therapy for complete control of gastro-oesophageal reflux disease symptoms. Analyses and comparisons of intra-oesophageal and intra-gastric pH profiles on therapy were then made.

RESULTS

One hundred and ten patients, 98 men and 12 women, with gastro-oesophageal reflux disease (n = 62) and/or Barrett's oesophagus (n = 48), were studied. All tolerated proton pump inhibitors well and were asymptomatic at the time of the study. Thirty-six (58%) patients with gastro-oesophageal reflux disease and 24 (50%) patients with Barrett's oesophagus (P = 0.4) normalized their intra-oesophageal pH profiles on proton pump inhibitors. Compared with patients with gastro-oesophageal reflux disease, patients with Barrett's oesophagus were more likely to have higher degree of pathologic acid reflux despite proton pump inhibitor therapy (DeMeester score 50.5 +/- 8.2 vs. 31.4 +/- 4.6, P = 0.03) and exhibited less intra-gastric acid suppression (% total pH < 4.0: 53.9 +/- 2.7 vs. 39.9 +/- 2.6, P = 0.0004), particularly supine (% pH < 4.0: 62.1 +/- 3.4 vs. 44.8 +/- 3.4, P = 0.0006).

CONCLUSIONS

Gastro-oesophageal reflux disease patients with or without Barrett's oesophagus continue to exhibit pathologic gastro-oesophageal reflux disease and low intra-gastric pH despite proton pump inhibitor therapy that accomplishes complete reflux symptom control. Further, intra-oesophageal and intra-gastric pH control is significantly more difficult to achieve in patients with Barrett's oesophagus. These findings may have significant therapeutic implications.

The prevalence of Helicobacter pylori infection and the status of gastric acid secretion in patients with Barrett's esophagus in Japan

OBJECTIVES

The acidity of the refluxate into the esophagus is a key factor for the pathogenesis of gastroesophageal reflux disease. Helicobacter pylori (H. pylori) infection can influence gastric acid secretion. We have reported that H. pylori infection prevents reflux esophagitis by decreasing gastric acid secretion in Japanese patients, but the role of this organism in Barrett's esophagus is unclear. The aim of this study was to investigate the prevalence of H. pylori infection and gastric acid secretion in Japanese patients with reflux esophagitis with or without Barrett's esophagus.

METHODS

We enrolled 112 reflux esophagitis patients who were examined for the status of H. pylori and acid secretion in this study. They were divided into three groups, according to the presence or absence of Barrett's esophagus as follows: reflux esophagitis group without Barrett's esophagus (reflux esophagitis alone) (80 patients); short-segment Barrett's esophagus group (16 patients); and long-segment Barrett's esophagus group (LSBE) (16 patients). Age- and sex-matched control subjects were also assigned to the 80 patients with reflux esophagitis alone. The prevalence of H. pylori infection was determined by histology, rapid urease tests, and serum IgG antibodies. Gastric acid secretion was evaluated by the endoscopic gastrin test (EGT).

RESULTS

The overall prevalence of H. pylori infection in the reflux esophagitis patient group (24.1%) was significantly lower than the control group (71.2%) (odds ratio 0.13, 95% confidence interval 0.07-0.24; p < 0.0001). The prevalence of H. pylori infection in the patients with Barrett's esophagus tended to be lower than that in the patients with reflux esophagitis alone (reflux esophagitis alone; 30.0%, SSBE; 18.7%, LSBE; 0%), especially in the patients with LSBE compared with the reflux esophagitis alone group (p < 0.01). The EGT value of the respective reflux esophagitis patient group was significantly higher than the control group. The EGT value in the patients with Barrett's esophagus tended to be higher than that in the patients with reflux esophagitis alone, but the difference was not statistically significant. When examined in H. pylori-negative subjects, no difference was found in the EGT value between the control subjects and the patients with reflux esophagitis alone, but it was significantly higher in patients with Barrett's esophagus than the control subjects (p < 0.05). On the other hand, when examined in the H. pylori-positive subjects, the EGT value was significantly higher in the patients with reflux esophagitis alone than in the control subjects (p < 0.01).

CONCLUSIONS

H. pylori infection may play a protective role in the development of Barrett's esophagus, especially in the development of LSBE in Japan. Gastric acid hypersecretion may be concerned with the development of Barrett's esophagus in addition to the absence of H. pylori infection.

Acid inhibition in GERD-how much is enough?

Gastric acid plays a fundamental role in the development of mucosal injury and symptoms in gastro-esophageal reflux disease(GERD). In this issue of the Journal, Milkes et al report the inability of proton pump inhibitor (PPIs) therapy to "normalize" 24-hour intraesophageal pH parameters despite good symptom control. Twenty-five of fifty H. pylori negative patients with chronic uncomplicated GERD failed to normalize their pH parameters. Failure of esophageal acid control correlated with inadequate gastric acid inhibition. These findings are provocative and interesting but difficult to reconcile against a large body of evidence supporting the superior therapeutic efficacy of PPIs in symptom control, healing of esophagitis, and decreasing the rate of dilations in patients with GERD. No information is provided regarding the status of the esophageal mucosa in patients failing to achieve normalization of pH values. This raises the question about the clinical significance of this finding: i.e., does the lack of normalization of esophageal pH parameters correlate with esophageal epithelial damage (endoscopically visible injury) or complications of the disease? The patient population for this study was highly selected, thus the true prevalence of this observation for the large pool of patients with GERD remains unknown. Despite this and other limitations, the study will likely stimulate further research to examine ultimately how much acid inhibition-and for how long-is critical to the healing of GERD and to prevent the complications of the disease.