Acid and non-acid reflux in patients with persistent symptoms despite acid suppressive therapy: a multicentre study using combined ambulatory impedance-pH monitoring

Pepsin in nonacidic refluxate can damage hypopharyngeal epithelial cells

OBJECTIVES

Studies using combined multichannel intraluminal impedance with pH monitoring reveal a role for nonacidic reflux in laryngopharyngeal symptoms and injury. We have discovered that pepsin is taken up by laryngeal epithelial cells by receptor-mediated endocytosis. This finding reveals a novel mechanism by which pepsin could cause cell damage, potentially even in nonacidic refluxate. The objective of this study was to determine whether pepsin, at pH 7.4 and thus in nonacidic refluxate, causes cell damage.

METHODS

Cultured hypopharyngeal epithelial (FaDu) cells were exposed to human pepsin (0.1 mg/mL) at pH 7.4 for either 1 hour or 12 hours at 37 degrees C and analyzed by electron microscopy, cytotoxicity assay, and SuperArray.

RESULTS

We report mitochondrial and Golgi complex damage in cells exposed to pepsin at neutral pH, observed by electron microscopy. We also report cell toxicity of pepsin at pH 7.4, measured by a cytotoxicity assay. Furthermore, using SuperArray, we found that pepsin at pH 7.4 significantly alters the expression levels of multiple genes implicated in stress and toxicity.

CONCLUSIONS

These findings are perhaps the first to explain why many patients have symptoms and injury associated with nonacidic reflux, and could have important implications for the development of new therapies for reflux, such as pepsin receptor antagonists and/or irreversible inhibitors of peptic activity.

Oesophageal acid hypersensitivity is not a contraindication to Nissen fundoplication

BACKGROUND

The Rome III criteria classify patients with a positive relationship between symptoms and reflux episodes but a physiological oesophageal acid exposure time as having gastro-oesophageal reflux disease (GORD) with an acid hypersensitive oesophagus. The long-term outcome of antireflux surgery in these patients was investigated.

METHODS

Outcomes of Nissen fundoplication in 28 patients with GORD refractory to proton-pump inhibitors (PPIs) and oesophageal acid hypersensitivity (group 1) were compared with those of 126 patients with pathological acid exposure (group 2).

RESULTS

Fundoplication had a similar effect in both groups. Three months after surgery, total acid exposure time and the prevalence of oesophagitis had decreased, whereas mean lower oesophageal pressure had increased. The percentage of patients using PPIs was reduced from 83 to 4 per cent in group 1 and from 86.1 to 7.4 per cent in group 2 (both P < 0.001). Quality of life measured on a scale from 0 to 100 improved from 52 to 69 (P = 0.009) and 64 (P < 0.001) respectively. The percentage of patients with resolved or improved symptoms at 5 years was similar.

CONCLUSION

Patients with oesophageal acid hypersensitivity benefit from Nissen fundoplication as much as those with pathological acid exposure.

Role of the gastric refluxate in gastroesophageal reflux disease: acid, weak acid and bile

The role of acid, weak/nonacid, and bile in the genesis of esophageal mucosal damage and reflux symptoms is complex. Acid combined with pepsin and unconjugated bile acids are critical to the development of esophagitis and Barrett's esophagus. Acid alone may be the principal factor in determining the severity of esophagitis. Weak acid or nonacid reflux does not cause esophageal damage or damage to adjacent organs, such as the larynx or lungs. The primary cause of heartburn and regurgitation is acid reflux, but a minority of symptoms (5%-15%) can be triggered by weak acid or bile reflux. The role is changed among patients on proton pump inhibitors with persistent symptoms, where the majority of symptoms are now due to weak acid or bile reflux. The proximal extent of the reflux, regardless of its acidity, seems to be the key to reflux symptoms.

Esophageal motility in nonacid reflux compared with acid reflux

Esophageal motility has been well studied in gastroesophageal reflux disease (GERD) and acid reflux, but not in nonacid reflux. Consecutive patients who had both 24-h multichannel intraluminal impedance-pH (MII-pH) and esophageal motility tests for suspected GERD were studied. Patients were grouped into nonacid refluxers, acid refluxers, and nonrefluxers based on positive symptom correlation and objective findings of acid reflux. Of 96 patients enrolled, 21 patients (22%) were nonacid refluxers, 44 patients (46%) were acid refluxers, and 31 patients (32%) had no objective evidence of reflux. Normal motility was recorded in 86% of nonacid refluxers, 71% of acid refluxers, and 60% of nonrefluxers. Ineffective esophageal motility was seen in 24% of acid refluxers, and 5% of nonacid refluxers (P = 0.11). Symptomatic nonacid reflux events comprised 22% of patients studied for GERD symptoms by MII-pH. Esophageal motility in nonacid reflux is normal 86% of the time.

Acid and non-acid reflux in Japanese patients with non-erosive reflux disease with persistent reflux symptoms, despite taking a double-dose of proton pump inhibitor: a study using combined pH-impedance monitoring

BACKGROUND

Combined multi-channel intra-luminal impedance and pH (Mll-pH) monitoring can detect gastro-esophageal reflux and identify acid and non-acid reflux (NAR) events. It can be used for patients with persistent symptoms who are having proton pump inhibitor (PPI) therapy. The aim of this study is to determine the frequency of acid reflux and NAR and to establish their relationship with persistent reflux symptoms in Japanese patients with non-erosive reflux disease (NERD) who are on a double-dose of PPI therapy.

METHODS

Thirteen patients with NERD, with persistent reflux symptoms, despite taking PPI at least twice daily, were included in this study. Twenty-four-hour combined Mll-pH monitoring was carried out on all patients and reflux episodes were detected by impedance channels, located at 3, 5, 7, 9, 15 and 17 cm above the lower esophageal sphincter (LES) and classified into acid reflux and NAR, based on pH data from 5 cm above the LES. A positive symptom index (SI) was declared, if at least half of the symptoms were preceded by reflux episodes within 5 min.

RESULTS

A total of 916 liquid reflux episodes were detected, and a total of 171 symptoms were recorded. Eight (4.7%) of 171 symptoms were related to acid reflux, and 68 (39.8%) were related to NAR. Seven (53.8%) patients had a positive SI and in these seven patients, a total of 79 symptoms were recorded. 5 (6.3%) of the 79 symptoms were related to acid reflux and 44 (55.7%) were related to NAR.

CONCLUSIONS

Persistent reflux symptoms, in SI-positive patients with NERD on double-dose PPI therapy, are more likely to be associated with primarily non-acid reflux.

[Gastro-esophageal reflux through gastric antisecretory drugs]

During the 20th century, gastro-esophageal reflux moved from the status of a rare and severe disease to that of a frequent disease occurring mostly, in the absence of any significant lesions. Proton pump inhibitors (PPIs) are the mainstay of its therapy and are prescribed mainly in an empirical way. Extradigestive manifestations require more accurate diagnostic tests and therapeutic management. The modalities of prescription of the PPIs quickly progressed toward the on-demand therapy and over-the-counter PPIs should become widespread. The relative failures of PPIs led to a profusion of new antisecretory agents but clinical improvements are presently disappointing and the rationale of this escalation is questionable. The concept of non acid gastro-esophageal reflux opens more innovative diagnostic and therapeutic perspectives which, however, must be validated. In this respect, endoscopic treatment needs more reliable techniques and more rigorous trials. Gastro-esophageal reflux refractory to PPIs corresponds mainly to functional esophageal disorders that need diagnostic and therapeutic improvements. Barrett's esophagus constitutes a major challenge for the next few years. Its screening and its prevention seem, for the moment, inaccessible. Its survey and the prevention of its complications should benefit from progress of diagnostic and interventional endoscopy.

Efficacy of esophageal impedance/pH monitoring in patients with refractory gastroesophageal reflux disease, on and off therapy

BACKGROUND & AIMS

Intraluminal impedance monitoring has given new dimensions to the diagnosis of reflux disease. However, there is no defined algorithm for evaluating refractory reflux symptoms. We studied whether combined impedance/pH monitoring in patients on therapy can predict acid reflux in patients off therapy and whether testing should be carried out when patients are on or off therapy.

METHODS

Thirty-nine adults (mean age, 50 years; 24 female) with refractory reflux symptoms were evaluated by impedance/pH monitoring while on therapy, followed by wireless pH monitoring while off therapy. Non-acid reflux events in patients on therapy were correlated with acid reflux parameters studied off therapy. In addition, the likelihood of test abnormalities on and off therapy was determined.

RESULTS

In 25 of 39 patients (64%) on therapy, impedance testing was normal, with a median of 69 events (interquartile, 63.0-78.0). The percentage of time at pH <4 was within the normal range for all patients who were on therapy. The pH test results were abnormal in 28 of 39 patients (72%) when studied off therapy. Ninety-three of patients with abnormal impedance on therapy also had abnormal acid reflux off therapy. When both groups were off therapy, the patients with abnormal impedance parameters on therapy had significantly higher median (interquartile) 2-day baseline levels of esophageal acid exposure (8.7%, 6.9%-12.5%), compared with those of patients with normal impedance parameters while on therapy (6.0%, 2.8%-9.4%; P = .026).

CONCLUSIONS

Abnormal impedance in patients on therapy predicts acid reflux in patients off therapy. In patients with refractory reflux, combined impedance/pH monitoring might provide the single best strategy for evaluation of reflux symptoms.

Does the presence of a hiatal hernia affect the efficacy of the reflux inhibitor baclofen during add-on therapy?

OBJECTIVES

Reflux inhibitors, like the gamma-aminobutyric acid type B (GABA(B)) receptor agonist, baclofen, block transient lower esophageal sphincter relaxations (TLESRs) and are proposed as an add-on therapy in patients with proton pump inhibitor (PPI)-resistant gastroesophageal reflux. However, as other mechanisms of reflux become more important in the presence of a hiatal hernia (HH), the efficacy of reflux inhibitors to reduce acid and non-acid exposure may be hampered. Therefore, we compared the effect of baclofen in patients with no HH (-HH) and those with a large HH during PPI treatment.

METHODS

A total of 27 gastroesophageal reflux disease (GERD) patients on PPI were included; 16 had -HH and 11 had a large (> or =3 cm) HH (+HH). During PPI treatment, the effect of baclofen (3 x 20 mg) on acid and non-acid reflux was evaluated in a randomized, double-blind, placebo-controlled cross-over study. Reflux was measured during 24 h using combined esophageal impedance and pH-metry.

RESULTS

The majority of reflux events consisted of both gaseous and liquid reflux with a significant increase in non-acid, mixed reflux episodes in +HH patients compared with those in -HH patients. Acid exposure time was in the normal range in both patient groups during both placebo and baclofen. In this study, baclofen significantly reduced the total number of reflux episodes with 36% in -HH patients and 43% in +HH patients, but did not change the number of acid reflux episodes or total acid exposure time.

CONCLUSIONS

This study shows that baclofen is also effective in patients with GERD with +HH, further underscoring the potential of reflux inhibitors as treatment of GERD.

Reflux profile of Chinese gastroesophageal reflux disease patients with combined multichannel intraluminal impedance-pH monitoring

BACKGROUND AND AIMS

To investigate the reflux profile of Chinese gastroesophageal reflux disease (GERD) patients with the aid of combined multichannel intraluminal impedance-pH (MII-pH) monitoring technique.

METHODS

Consecutive patients presented with GERD symptoms were enrolled to erosive esophagitis (EE) group, non-erosive reflux disease (NERD) group and functional heartburn (FH) group after upper endoscopy, combined MII-pH monitoring and rabeprazole test. Another 20 healthy controls (HC) were recruited.

RESULTS

Sixty-four GERD patients (EE:20, NERD:22, FH:22, HC:20) were enrolled. There were more episodes of liquid reflux and proximal reflux in EE and NERD groups than that in FH and HC groups (P < 0.05). Patients in FH and HC groups had higher proportion of mixed reflux (P = 0.000). The percentage of acid reflux in EE and NERD was much higher, while there was a higher percentage of weakly acidic reflux in FH and HC (P = 0.000). No significant difference was found in MII-pH parameters between groups with and without response to rabeprazole test except recumbent percentage time of esophageal pH value below 4 and episodes of proximal reflux.

CONCLUSION

Erosive esophagitis and NERD patients had more liquid and proximal reflux episodes than FH patients and healthy controls. Acid and liquid reflux was predominant in the former two groups, while weakly acidic and mixed reflux was predominant in the latter two groups.

Utility of non-endoscopic investigations in the practical management of oesophageal disorders

The current available methods for diagnosis of GORD are symptom questionnaires, catheter and wireless pH-metry, impedance-pH monitoring and Bilitec(@). Osophageal pH monitoring allows both quantitative analysis of acid reflux and assessment of reflux-symptom association. Impedance-pH monitoring detects all types of reflux (acid and non-acid) and allows assessment of proximal extent of reflux, a relevant parameter for understanding symptoms perception and extraoesophageal symptoms. Bilitec provides a quantitative assessment of duodeno-gastro-oesophageal reflux. Oesophageal motor abnormalities have been associated with GORD symptoms as well as chest pain and dysphagia. High-resolution manometry contributed to re-classify oesphageal motor disorders. However, barium swallows are still essential for evaluation of oesophageal anatomy and combined oesophageal manometry-impedance can assess oesophageal motility and bolus transit simultaneously in a non-radiological way. Still in experimental phase, high-frequency ultrasound allows monitoring of the oesophageal wall thickness and exaggerated longitudinal muscle contraction that might be associated to chest pain and dysphagia. This chapter provides a critical evaluation of the clinical application of these techniques.

Reflux monitoring: pH-metry, Bilitec and oesophageal impedance measurements

Gastro-oesophageal reflux disease (GERD) is a highly prevalent condition in Western countries leading to millions of outpatient visits per year. GERD symptoms including heartburn, regurgitation and chest pain are caused by reflux of gastric content in the oesophagus even in the absence of endoscopically visible mucosal lesions. Several procedures are used to identify gastro-oesophageal reflux, the clinically widely used are: conventional (catheter-based) pH monitoring, wireless oesophageal pH monitoring (Bravo), bilirubin monitoring (Bilitec), and combined multichannel intraluminal impedance-pH monitoring (MII-pH). Each technique has strengths and limitations of which clinicians and investigators should be aware when deciding which to choose in a particular patient. Important is the ability to quantify gastro-oesophageal reflux and evaluate the relationship between symptoms and reflux episodes. The present review summarises the technical aspects in performing and interpreting esophageal reflux monitoring procedures.

Gastroesophageal reflux disease and idiopathic pulmonary fibrosis

Gastroesophageal reflux disease occurs with a higher prevalence in patients with idiopathic pulmonary fibrosis than in matched controls. Silent reflux occurs in about a third of patients with significant gastroesophageal reflux disease; thus, objective measurements are required to evaluate gastroesophageal reflux disease in patients with advanced lung diseases. We provide here a detailed description of acid and non-acid reflux and the diagnostic evaluation for pulmonologists and lung transplant surgeons suspecting reflux as a contributing factor in advanced lung diseases. We review the evidence for gastroesophageal reflux disease causing idiopathic pulmonary fibrosis and other select pulmonary diseases and the potential role of antireflux surgery in the management of advanced lung disease and transplant patients.

Effects of half-solid nutrients on gastroesophageal reflux in beagle dogs with or without cardioplasty and intrathoracic cardiopexy

BACKGROUND

Percutaneous endoscopic gastrostomy (PEG) has become an important modality to provide enteral access for long-term nutritional support. Nevertheless, aspiration of liquid nutrients due to vomiting and reflux esophagitis caused by gastroesophageal reflux (GER) is a significant problem associated with tube feeding by PEG.

MATERIALS AND METHODS

First, gastrostomy as an access for enteral nutrition and esophagostomy for gastroesophageal pH and Bilitec monitoring were performed in eight beagle dogs, in which the influence of viscosity of an enteral formula on the degree of GER was investigated using a commercially available liquid meal and a nearly isocaloric half-solid diet that was prepared by adding a solution mixed with dextrin, pectin, and calcium lactate. Second, similar studies were accomplished in seven beagle dogs that underwent cardioplasty and intrathoracic cardiopexy (a model of GER disease [GERD]).

RESULTS

There was no difference in the degree of GER evaluated by Bilitec monitoring between liquid and half-solid nutrients in eight normal dogs, whereas solidifying nutrients significantly reduced the frequency of reflux during the feeding periods (P=0.0180) and post-feeding periods (P=0.0277) in a model of GERD.

CONCLUSION

The use of half-solid nutrients for enteral feeding reduced the frequency of reflux in a dog model of GERD.

Cough and gastroesophageal reflux: insights from animal models

Chronic cough in gastroesophageal reflux disease (GERD) has been attributed to irritation of the esophagus and/or upper airways by reflux of gastric content. Animal models have provided insight into both of these putative mechanisms. In patients with chronic cough and GERD, stimuli associated with reflex in the esophagus sensitize the cough reflex. This sensitization can be reproduced in the guinea pig and is most likely mediated by the esophageal afferent nerve fibers carried by the vagus nerves. Studies in animals have identified several subtypes of vagal esophageal C-fibers that may subserve this function. The putative nociceptive vagal C-fibers in the guinea pig esophagus are stimulated by acid and express the TRPV1 and TRPA1 receptors that confer responsiveness to disparate noxious stimuli. Acute and/or chronic irritation of the upper airways by reflux may contribute to cough by stimulation and/or sensitization of the airway afferent nerves. Studies in animals have identified airway nerves that likely initiate cough due to aspirated reflux; have characterized their pharmacology; and have provided insight into changes of their sensitivity. Studies in animal models have also described the neurophysiology of reflexes that protect the airways from reflux. In conclusion, animal models provide mechanistic insight into the modulation of cough from the esophagus and the pharmacology of neural pathways mediating cough in GERD.

Proton pump inhibitor failure--what are the therapeutic options?

Proton pump inhibitor (PPI) failure is very common and may affect up to one-third of the PPI consumers. Identifying the underlying mechanisms for PPI failure in each individual patient is essential for treatment success. For residual acid reflux, increasing the PPI dose to twice daily; switching to another PPI, or adding an histamine 2 receptor antagonist could be a successful therapeutic strategy. In patients with duodenogastroesophageal reflux, weak acidic/alkaline reflux and hypersensitivity to acid reflux, therapeutic modalities that reduce transient lower esophageal sphincter relaxation or visceral pain could be entertained. Treatment of PPI failure due to delayed gastric emptying should be focused on improving gastric motor activity. Psychological management may supplement any medical or surgical approach toward PPI failure.

The role of gastroesophageal reflux in exercise-triggered asthma: a randomized controlled trial

BACKGROUND

Exercise-triggered asthma (ETA) develops when physical activity triggers asthma symptoms during or directly after exercise. In patients prone to symptoms of supra-esophageal reflux, exercise may trigger gastroesophageal reflux (GER), resulting in such symptoms.

AIMS

To determine the prevalence of abnormal pH in patients with ETA and to determine whether acid suppression improves symptoms in ETA patients.

METHODS

We performed a randomized double-blind trial of rabeprazole versus placebo in the treatment of patients with ETA. Patients underwent treadmill protocol to determine their VO(2 max). Next, pH testing was initiated while undergoing a 30-min treadmill program exercising them at 65% of their VO(2 max). They were subsequently randomized to rabeprazole or placebo for 10 weeks. At the end of 10 weeks, exercise testing was repeated.

RESULTS

A total of 31 patients completed the study (20 asthmatics, 11 non-asthmatics). Twenty-two out of 30 (73%) subjects had abnormal pH studies. For all subjects, rabeprazole improved symptoms more than placebo (P = 0.03). The association was stronger in the pH-positive group (P = 0.009).

CONCLUSION

Acid reflux is common in ETA patients. Many patients with exercise-related respiratory symptoms are misdiagnosed as chronic asthmatics. Exercise-related symptoms improve with the use of acid suppression. This study suggests that ETA patients may benefit from acid suppression.

Symptoms with acid and nonacid reflux may be produced by different mechanisms

Twenty-four-hour multichannel intraluminal impedance and pH (MII-pH) esophageal monitoring detects both acid and nonacid gastroesophageal reflux episodes. The MII-pH catheter contains six impedance segments placed 3, 5, 7, 9, 15, and 17 cm above the lower esophageal sphincter (LES). A pH electrode at 5 cm above the LES identifies the type of reflux, i.e. acid or nonacid. Patients with acid and nonacid reflux exhibit typical and atypical symptoms often within 5 min following a reflux episode. The aim of this study is to compare the timing of symptoms after reflux episodes in patients with acid and nonacid reflux. Methods include a review of 70 MII-pH tracings (42 females, mean age 40, range 18-85 years) either on (50 points) or off (20 points) acid suppression therapy. Typical (heartburn, regurgitation) and atypical (cough) symptoms with acid or nonacid reflux episodes detected by impedance were analyzed. Symptoms were considered positive with acid reflux if there was a pH drop to <4, plus an MII detected a reflux episode and with nonacid reflux if pH remained >4 and MII detected a reflux episode. The timing of the symptom after each reflux episode was recorded. Symptom perception occurred significantly sooner after acid versus nonacid reflux (P < 0.05). Acid reflux episodes are more likely to be perceived in the first 2 min following the reflux episode. Patients with acid reflux are likely to perceive symptoms earlier, and symptoms with acid and nonacid reflux may be produced by different mechanisms.

Nocturnal weakly acidic reflux promotes aspiration of bile acids in lung transplant recipients

BACKGROUND

Gastroesophageal reflux (GER) and aspiration of bile acids have been implicated as non-alloimmune risk factors for the development of bronchiolitis obliterans syndrome (BOS) after lung transplantation. The aim of our study was to investigate the association between GER and gastric aspiration of bile acids and to establish which reflux characteristics may promote aspiration of bile acids into the lungs and may feature as a potential diagnostic tool in identifying lung transplantation (LTx) patients at risk for aspiration.

METHODS

Twenty-four stable LTx recipients were studied 1 year after transplantation. All patients underwent 24-hour ambulatory impedance-pH recording for the detection of acid (pH <4) and weakly acidic (pH 4 to 7) reflux. On the same day, bronchoalveolar lavage fluid (BALF) was collected and then analyzed for the presence of bile acids (Bioquant enzymatic assay).

RESULTS

Increased GER was detected in 13 patients, of whom 9 had increased acid reflux and 4 had exclusively increased weakly acidic reflux. Sixteen patients had detectable bile acids in the BALF (0.6 [0.4 to 1.5] micromol/liter). The 24-hour esophageal volume exposure was significantly increased in patients with bile acids compared to patients without bile acids in the BALF. Acid exposure and the number of reflux events (total, acid and weakly acidic) were unrelated to the presence of bile acids in the BALF. However, both nocturnal volume exposure and the number of nocturnal weakly acidic reflux events were significantly higher in patients with bile acids in the BALF.

CONCLUSIONS

Weakly acidic reflux events, especially during the night, are associated with the aspiration of bile acids in LTx recipients and may therefore feature as a potential risk factor for the development of BOS.

Activity/Stability of Human Pepsin: Implications for Reflux Attributed Laryngeal Disease

OBJECTIVES/HYPOTHESIS

Exposure of laryngeal epithelia to pepsin during extra-esophageal reflux causes depletion of laryngeal protective proteins, carbonic anhydrase isoenzyme III (CAIII), and squamous epithelial stress protein Sep70. The first objective of this study was to determine whether pepsin has to be enzymatically active to deplete these proteins. The second objective was to investigate the effect of pH on the activity and stability of human pepsin 3b under conditions that might be found in the human esophagus and larynx.

STUDY DESIGN

Prospective translational research study.

METHODS

An established porcine in vitro model was used to examine the effect of active/inactive pepsin on laryngeal CAIII and Sep70 protein levels. The activity and stability of pepsin was determined by kinetic assay, measuring the rate of hydrolysis of a synthetic pepsin-specific substrate after incubation at various pH values for increasing duration.

RESULTS

Active pepsin is required to deplete laryngeal CAIII and Sep70. Pepsin has maximum activity at pH 2.0 and is inactive at pH 6.5 or higher. Although pepsin is inactive at pH 6.5 and above, it remains stable until pH 8.0 and can be reactivated when the pH is reduced. Pepsin is stable for at least 24 hours at pH 7.0, 37 degrees C and retains 79% +/- 11% of its original activity after re-acidification at pH 3.0.

CONCLUSIONS

Detectable levels of pepsin remain in laryngeal epithelia after a reflux event. Pepsin bound there would be enzymatically inactive because the mean pH of the laryngopharynx is pH 6.8. Significantly, pepsin could remain in a form that would be reactivated by a subsequent decrease in pH, such as would occur during an acidic reflux event or possibly after uptake into intracellular compartments of lower pH.

Review article: intra-oesophageal impedance monitoring for the assessment of bolus transit and gastro-oesophageal reflux

BACKGROUND

Intra-oesophageal impedance monitoring can be used to assess the clearance of a swallowed bolus (oesophageal transit) and to detect gastro-oesophageal reflux independent of its acidity.

AIM

To discuss the clinical application of the impedance technique for the assessment of bolus transit and gastro-oesophageal reflux.

METHODS

Review of the literature on intra-oesophageal impedance monitoring of bolus transit and gastro-oesophageal reflux.

RESULTS

Using impedance criteria, normal oesophageal bolus clearance can be defined as complete clearance of at least 80% of liquid boluses and at least 70% of viscous boluses. Impedance recording identifies oesophageal function abnormalities in non-obstructive dysphagia patients and in patients with postfundoplication dysphagia. The impedance technique seems to be less suitable for the most severe end of the dysphagia spectrum like achalasia. Intra-oesophageal impedance monitoring detects reflux events independent of the pH of the refluxate, which allows identification of non-acid reflux episodes. In addition, use of impedance monitoring enables assessment of the composition (liquid, gas, mixed) and proximal extent of the refluxate. Combined impedance-pH monitoring is more accurate than pH alone for the detection of both acid and weakly acidic reflux. Furthermore, addition of impedance monitoring to pH increases the yield of symptom association analysis both in patients off and on proton pump inhibitor therapy.

CONCLUSIONS

Intra-oesophageal impedance monitoring is a feasible technique for the assessment of bolus transit and gastro-oesophageal reflux. Combined impedance-manometry provides clinically important information about oesophageal function abnormalities and combined impedance-pH monitoring identifies the relationship between symptoms and all types of reflux events regarding acidity and composition.

Functional heartburn: what it is and how to treat it

Functional heartburn is considered one of the most common functional esophageal disorders. The disorder is more common in young women and is associated with other functional bowel disorders and psychological co-morbidity, primarily somatization. The etiology of functional heartburn remains unknown. Most patients, however, demonstrate esophageal hypersensitivity. Functional heartburn has been identified as the main cause for proton pump inhibitor (PPI) failure in patients with heartburn. Treatment is still a challenge, and patients should be started with PPI treatment. In non-responders, escalation of the PPI dose could be attempted and, if unsuccessful, pain modulators should be prescribed.

Gastroesophageal reflux monitoring: pH (catheter and capsule) and impedance

Diagnostic testing for GERD has evolved to include multi esophageal sites (distal, proximal and hypopharyngeal monitoring), wireless pH, and oropharyngeal devices. The versatility of the devices has increased our ability to better understand the role of acid reflux in various disorders involving reflux of acid. Wireless pH monitoring improves patient comfort and allows monitoring for gastroesophageal reflux events over several days. Ambulatory MII-pH monitoring is another exciting diagnostic tool, which is capable of detecting more than one type of reflux and achieves higher sensitivity and specificity to detect GERD than endoscopy or pH-metry. It is useful in patients with either typical or atypical reflux symptoms who are refractory to proton pump inhibitor (PPI) therapy. In this setting, MII-pH can be performed on PPI therapy to assess the efficacy of PPIs and the role of nonacid or acid reflux in persistent symptoms.

Ambulatory monitoring of GERD: current technology

Various techniques have been devised to diagnose, characterize, and classify gastroesophageal reflux (GER). Stationary techniques, such as fluoroscopy and scintigraphy, provide interesting anatomic and functional information related to GER but are not sensitive enough and are usually performed in nonphysiologic conditions. Ambulatory techniques for GER monitoring have been developed and used since 1974. The current available techniques include catheter and wireless pH-metry, Bilitec, and impedance-pH monitoring. Prolonged wireless pH monitoring can be useful to evaluate patients off and on proton pump inhibitor (PPI) treatment. Impedance-pH monitoring is being used increasingly in patients who have persistent symptoms on PPI therapy because it can establish an association between symptoms and weakly acidic or nonacid reflux. Bilitec is performed in patients suspected to have increased duodenogastroesophageal reflux (DGER). This article discusses the technical details, clinical indications, and applications of these diagnostic techniques.

Medical management of gastroesophageal reflux disease

Antisecretory therapies that raise intragastric pH provide the best healing of the esophageal mucosal damage that occurs in gastroesophageal reflux disease. Continuous maintenance therapy is also effective to reduce the likelihood of recurrence of esophagitis and control symptoms in the long term. Proton pump inhibitor (PPI) therapy is an effective approach for healing esophagitis and controlling symptoms. Endoscopic and surgical treatments may provide an option for patients who are refractory to PPIs in whom reflux has been clearly demonstrated. Long-term antireflux medication is often needed after surgical treatment because of persisting or recurrent pathologic reflux and symptoms. An alternative approach to controlling transient lower esophageal sphincter relaxations, such as the GABA-B agonists, deserves further study.

New diagnostic techniques for esophageal disorders

Esophageal disorders are common in the general population and can be associated with significant morbidity. Several new diagnostic techniques for esophageal disorders have become available in recent years. These include capsule pH-metry, high-resolution manometry, impedance combined with either pH-metry or manometry, and high-frequency ultrasound. Capsule pH-metry is useful in children and in patients who cannot tolerate the conventional pH-metry catheter. It has the advantage of not interfering with a patient's usual meals and activities during the 24 h study. High-resolution manometry is easier to perform and interpret than conventional manometry. This has led to improved diagnosis of various esophageal motility disorders. Impedance measures the movement of liquid and gas in the esophagus. When combined with pH-metry, impedance can confirm that retrograde bolus movement (ie, reflux) is occurring while simultaneously measuring changes in pH levels. It has also highlighted the importance of weakly acidic reflux in patients who do not respond to proton pump inhibitors. Weakly acidic reflux cannot be diagnosed with pH-metry alone. Impedance combined with manometry can determine whether a manometric abnormality leads to abnormal bolus clearance. In the past, this was performed with fluoroscopy, yet impedance is equally effective and does not carry the risk of increased radiation exposure. High-frequency ultrasound is currently a research tool to image the esophageal wall, particularly the two muscle layers, in real time during swallows and at rest. It has broadened our understanding of the pathophysiology of esophageal motility disorders.

Gastroesophageal reflux disease and connective tissue disorders: pathophysiology and implications for treatment

INTRODUCTION

It has been postulated that in patients with connective tissue disorders (CTD) and gastroesophageal reflux disease (GERD), esophageal function is generally deteriorated, often with complete absence of peristalsis. This belief has led to the common recommendation of avoiding antireflux surgery for fear of creating or worsening dysphagia.

METHODS

We hypothesized that in most patients with CTD and GERD: (a) esophageal function is often preserved; (b) peristalsis is more frequently absent when end-stage lung disease (ESLD) is also present; (c) a tailored surgical approach (partial or total fundoplication) based on the findings of esophageal manometry allows control of reflux symptoms without a high incidence of postoperative dysphagia. Forty-eight patients with CTD were evaluated by esophageal manometry and 24-hour pH monitoring (EFT). Twenty patients (group A) had EFT because of foregut symptoms, and 28 patients with ESLD (group B) had EFT as part of the lung transplant evaluation. Two hundred and eighty-six consecutive patients with GERD by pH monitoring served as a control group (group C). A laparoscopic fundoplication was performed in two group A patients (total), eight group B patients (three patients total, five patients partial) and in all group C patients (total).

RESULTS

Esophageal peristalsis was preserved in all patients with CTD and GERD. In contrast, peristalsis was absent in about half of patients when ESLD was also present. A tailored surgical approach resulted in control of reflux symptoms in all patients. One patient only developed postoperative dysphagia, which resolved with two Savary dilatations.

CONCLUSION

These data show that esophageal motor function is preserved in most patients with CTD, so that they should be offered antireflux surgery early in the course of their disease to prevent esophageal and respiratory complications. In patients with ESLD in whom peristalsis is absent, a partial rather than a total fundoplication should be performed, as it allows control of reflux symptoms while avoiding postoperative dysphagia.

The role of nonacid reflux in NERD: lessons learned from impedance-pH monitoring in 150 patients off therapy

INTRODUCTION

Nonerosive reflux disease (NERD) is the most common form of gastroesophageal reflux disease. While the role of acid reflux has been established, the relevance of nonacid reflux in generating symptoms in NERD is unknown.

AIM

To evaluate the diagnostic utility of impedance-pH monitoring in NERD patients.

METHODS

Patients with typical reflux symptoms (heartburn and/or regurgitation) and normal endoscopy (NERD) underwent a combined impedance-pH monitoring off proton pump inhibitor (PPI) therapy. Previously investigated 48 healthy volunteers served as controls. Distal esophageal acid exposure (% time pH < 4), number of acid and nonacid reflux episodes, 2-min window symptom index (SI; positive if > or = 50%), and symptom association probability (SAP; positive if > or = 95%) were calculated.

RESULTS

Between June 2004 and June 2007, 150 NERD patients (82 women, mean age 48 yr, range 18-78 yr) reported symptoms during the impedance-pH monitoring. NERD patients had more reflux episodes (median [25th-75th percentile]) compared with healthy volunteers (total: 46 [26-65] vs 32 [18-43], P < 0.05; acid: 29 [14-43] vs 17 [8.5-31.0], P < 0.05; and nonacid: 20 [15-27] vs 18 [13.5-26.0], P = NS). Sixty-three (42%) patients had abnormal % time pH < 4. Among 87 patients with normal % time pH < 4., 22 (15%) had a positive SAP for acid, 19 (12%) for nonacid reflux, and 7 (5%) for both. Classifying patients with symptomatic nonacid reflux as having a hypersensitive esophagus reduced the number of patients with functional heartburn from 65 (43%) to 39 (26%).

CONCLUSION

Monitoring for nonacid reflux in NERD patients reduces the proportion of patients classified as having "functional heartburn." Studies assessing the clinical implications of these findings are warranted.

Refractory GERD: what is it?

Refractory gastroesophageal reflux disease (GERD) is very common and may affect up to 40% of patients who use a proton pump inhibitor (PPI) once daily. Refractory GERD can present as incomplete or lack of response to PPI therapy. The disorder is clearly driven by patients, who present with a wide range of symptom severity and frequency while on PPI treatment. Poor compliance and improper timing of PPI consumption should always be excluded before further evaluation of this patient population. The putative mechanisms for refractory GERD include weakly acidic reflux, duodenogastroesophageal/bile reflux, visceral hypersensitivity, delayed gastric emptying, psychological comorbidity, and concomitant functional bowel disorders. Reduced PPI bioavailability, rapid PPI metabolism, PPI resistance, nocturnal reflux, and Helicobacter pylori infection status have very limited roles in refractory GERD. The contribution of eosinophilic esophagitis to refractory GERD is still unknown. Pill-induced esophagitis, Zollinger-Ellison syndrome, achalasia, and other disorders are rarely responsible for PPI failure and usually are not confused with GERD.

Diagnostic options for patients with refractory GERD

Patients with refractory gastroesophageal reflux disease (GERD) are those who have persistent symptoms while being treated with proton pump inhibitors (PPIs). One third of GERD patients requiring a daily PPI are estimated to eventually experience treatment failure. These patients are usually referred for further investigation to confirm the presence of GERD or to identify other entities as the cause of symptoms. Tools that can be used in this diagnostic process include upper gastrointestinal endoscopy with analysis of esophageal biopsies, esophageal pH monitoring, impedance-pH monitoring, and esophageal bilirubin monitoring. The conventional diagnostic approach includes upper gastrointestinal endoscopy and ambulatory pH monitoring while receiving PPI therapy. New diagnostic techniques that may be useful with refractory GERD include impedance-pH monitoring, which is very sensitive in detecting persistent weakly acidic reflux, and bilirubin monitoring, which detects increased esophageal exposure to bile. Gastric pH monitoring should be reserved for patients in whom PPI resistance is suspected.

Laryngeal manifestations of gastroesophageal reflux disease

Chronic laryngeal signs and symptoms associated with gastroesophageal reflux disease (GERD) are often referred to as reflux laryngitis or laryngopharyngeal reflux (LPR). It is estimated that up to 15% of all visits to otolaryngology offices are because of manifestations of LPR. Damage to laryngeal mucosa may be the result of reflux of gastroduodenal contents, whether chronic or a single incident. The most common presenting symptoms of LPR include hoarseness, sore throat, throat clearing, and chronic cough. The diagnosis of LPR is usually made on the basis of presenting symptoms and associated laryngeal signs, including laryngeal edema and erythema. The current recommendation for managing these patients is empiric therapy with twice-daily proton pump inhibitors for 1 to 2 months. Other causes of laryngeal irritation are considered in most of those who are unresponsive to such therapy. Surgical fundoplication is most effective in those who are responsive to acid-suppressive therapy.

Reflux cough

Cough can be an extraesophageal manifestation of gastroesophageal reflux disease. This article summarizes recent progress in our understanding of the pathophysiology, diagnosis, and treatment of the reflux cough syndrome. Recent studies have provided further evidence for a role of weakly acidic gastroesophageal reflux in inducing cough. It has also been established that although reflux may induce cough, cough may also trigger reflux in some patients, and distinguishing between the two requires objective detection of cough burst (ie, by esophageal manometry). Treatment of the reflux cough syndrome is an issue of ongoing controversy and further studies.

[Reasons for proton-pump-inhibitor failure in the treatment of gastroesophageal reflux disease]

The introduction of proton pump inhibitors (PPI) has facilitated the successful management of patients with gastroesophageal reflux disease (GERD). In a minor, but still relevant proportion of patients with GERD-like symptoms, PPI therapy has also proved to be ineffective. In such cases, the first question to be answered is if the symptoms and complaints are related to GERD indeed, or another disorder should be searched for. If GERD is still the most likely diagnosis, patients' compliance should be thoroughly investigated before any further diagnostic and therapeutic measure is taken. If PPI failure is not a result of inadequate management of GERD, there are several other disorders to be ruled out. In our review, we summarize the most important differential diagnostic issues of PPI failure.

Esophageal pH-impedance monitoring in patients with therapy-resistant reflux symptoms: 'on' or 'off' proton pump inhibitor?

BACKGROUND

In patients with proton pump inhibitor (PPI)-resistant symptoms, ambulatory 24-h pH-impedance monitoring can be used to assess whether a relationship exists between symptoms and reflux episodes. Until now, it is unclear whether combined pH-impedance monitoring in these patients should be performed on or off PPI.

METHODS

Thirty patients with symptoms of heartburn, chest pain, and/or regurgitation despite PPI twice daily underwent ambulatory 24-h pH-impedance monitoring twice, once on PPI and once after cessation of the PPI for 7 days. The order of the measurements was randomized. Reflux episodes were identified and classified as acid, weakly acidic, or weakly alkaline reflux. In addition, the symptom association probability (SAP) was calculated for each measurement.

RESULTS

The total number of reflux episodes and proximal extent were not affected by PPI therapy. On PPI, there were fewer acid reflux episodes (49 +/- 34 off PPI vs 20 +/- 25 on PPI) while more weakly acidic reflux episodes were identified (24 +/- 17 off PPI vs 48 +/- 31 on PPI). Symptom association analysis identified 15 and 11 patients with a positive SAP in the measurement off and on PPI, respectively, the difference in yield of the SAP not being statistically significant. Eight of the 19 patients who had no symptoms or a negative SAP during measurement on PPI had a positive SAP off PPI therapy. In contrast, only 4 patients with a positive SAP on PPI were missed in the measurement off PPI therapy.

CONCLUSIONS

In order to demonstrate or exclude GERD in patients with PPI-resistant symptoms, ambulatory 24-h pH-impedance monitoring should preferably be performed after cessation of PPI therapy because this approach seems to offer the best chance to assess a relationship between symptoms and reflux episodes.

Multichannel intraluminal impedance and pH monitoring in gastroesophageal reflux disease

The role of acid is very well established in the pathogenesis of gastroesophageal reflux disease and acid suppression constitutes the main approach to its medical treatment. With the current frequent use of proton pump inhibitors, we are seeing increasing numbers of patients in whom symptoms persist despite pharmacological acid suppression. Reflux monitoring has been traditionally performed through esophageal pH measurement to detect acid reflux (i.e., drops in esophageal pH to below 4.0). Multichannel intraluminal impedance and pH measurement constitutes an important development in reflux monitoring because, in addition to detecting acid reflux, it enables measurement of nonacid reflux (i.e., with a pH >4.0, also known as 'weakly acidic' for pH >4 but <7, or 'weakly alkaline' if pH >7), which may be responsible for symptoms in some patients who are being treated with proton pump inhibitors. This review describes the approach to measuring nonacid reflux, the possible mechanisms responsible for symptoms due to this type of reflux, the clinical importance of this phenomenon and available treatment options; and the role of multichannel intraluminal impedance and pH monitoring in the evaluation of refractory gastroesophageal reflux disease.

Meta-analysis: high-dose proton pump inhibitors vs. standard dose in triple therapy for Helicobacter pylori eradication

BACKGROUND

The evidence on whether high-dose proton pump inhibitors (PPIs) increase cure rates of Helicobacter pylori treatment has not been previously assessed.

AIM

To evaluate the evidence on the usefulness of high-dose PPI in standard triple therapy by performing a systematic review and a meta-analysis.

METHODS

A systematic search was performed in multiple databases and in the abstracts submitted to the Digestive Diseases Week, the European Helicobacter Study Group congress and the United European Gastroenterology Week. Randomized trials comparing a standard dose of a PPI with high-dose PPI both twice a day in triple therapy combining a PPI plus clarithromycin and either amoxicillin or metronidazole were selected. Relative risk (RR) and 95% confidence intervals (95% CIs) for all comparisons were calculated using Review Manager.

RESULTS

Six studies fulfilled the inclusion criteria. All used triple therapy for 7 days. A mean intention-to-treat cure rate of 82% was achieved with high-dose PPI and one of 74% with standard dose (RR: 1.09; 95% CI: 1.01-1.17). Subgroup analysis showed that the maximum increase was observed when the PPI compared were omeprazole 20 mg or pantoprazole 40 mg vs. esomeprazole 40 mg.

CONCLUSION

High-dose PPI seems more effective than standard-dose for curing H. pylori infection in 7-day triple therapy.

Yield of 24-hour esophageal pH and bilitec monitoring in patients with persisting symptoms on PPI therapy

Current management algorithms propose pH monitoring under proton pump inhibitors (PPIs) in suspected gastroesophageal reflux disease (GERD) with insufficient treatment response, but recent observations challenge this approach because of its low yield.

AIM

To perform an audit of the outcomes of pH monitoring under PPI therapy in our unit, and to study the yield of additional nonacid reflux monitoring.

METHODS

All pH monitoring studies under antireflux therapy since 1997, with or without simultaneous Bilitec monitoring, were analyzed.

RESULTS

From 1997 to 2003, 347 patients (157 men, mean age 49.4 +/- 0.8 years) underwent pH studies on PPI therapy (28% half-, 67% full-, and 5% double-dose PPI) for persisting typical (53%) or atypical (75%) symptoms. In 184 patients, simultaneous Bilitec monitoring was performed. Esophageal pH monitoring on PPI was pathological in 105 (30%) patients. Pathological pH monitoring on PPI was associated with typical reflux symptoms (64 versus 52%, P = 0.03), and a higher prevalence of persisting esophagitis (54 versus 36%, P < 0.005) and of hiatal hernia (58 versus 27%, P < 0.005). Bilitec monitoring on PPI therapy was pathological in 114 (62%) patients, of which 74 (40%) had normal pH monitoring. Adding Bilitec increased the rate of abnormal results over pH monitoring alone, from 38% to 69% on half-dose, from 27% to 69% on full-dose, and from 0% to 38% on double-dose PPI.

CONCLUSIONS

The rate of abnormal pH monitoring in symptomatic GERD patients while on PPI therapy is relatively low, especially in those on double-dose PPI. Combined pH and Bilitec monitoring significantly increased the rate of ongoing pathological reflux compared to pH alone in refractory to PPI therapy GERD patients.

Mucin Gene Expression in Human Laryngeal Epithelia: Effect of Laryngopharyngeal Reflux

Objectives:

We sought to document the mucin gene profile in normal human laryngeal epithelium and compare it with that in patients with reflux-attributed laryngeal injury or disease. We also investigated the effect of low pH with or without pepsin on mucin messenger RNA levels in vitro.

Methods:

Laryngeal biopsy specimens were obtained from 3 patients with clinically diagnosed laryngopharyngeal reflux and from 2 control subjects who had no signs or symptoms of reflux. Signs and symptoms were assessed by the Reflux Finding Score and the Reflux Symptom Index, respectively. Reverse transcription–polymerase chain reaction (RT-PCR) was performed to establish the mucin gene profile. Human hypopharyngeal epithelial cells were exposed to pH 7, 5, 4, and 2 with and without pepsin (0.1 mg/mL) for 20 minutes at 37°C, and expression of selected mucins was analyzed via real-time RT-PCR.

Results:

Mucin 1–5, 7, 9, 13, 15, 16, and 18–20 transcripts were detected in normal laryngeal epithelium, whereas mucin 6, 8, and 17 transcripts were not. Mucins 2, 3, and 5 were expressed at reduced levels in patients with reflux-attributed laryngeal injury or disease. These mucin genes were up-regulated after exposure to low pH in vitro (p < 0.005). Pepsin inhibited this up-regulation (p < 0.001).

Conclusions:

Reflux laryngitis is associated with down-regulation of mucin gene expression.