Reproducibility of esophageal high-resolution manometry

BACKGROUND

  Esophageal high-resolution manometry (HRM) is a novel method for esophageal function testing that has prompted the development of new parameters for quantitative analysis of esophageal function. Until now, the reproducibility of these parameters has not been investigated.

METHODS

Twenty healthy volunteers underwent HRM on two separate days. Standard HRM parameters were measured. In addition, in conventional (virtual) line tracings, lower esophageal sphincter (LES) resting pressure, relaxation pressure, and relative relaxation pressure were measured. Firstly, for each variable, the mean percentage of covariation (100×SD/mean: %COV) was derived as a measure of inter- and intra-individual variation. Secondly, Kendall's coefficients of concordance (W values) were calculated. Thirdly, Bland-Altman plots were used to express concordance graphically.

KEY RESULTS

Statistically significant concordance values were found for upper esophageal sphincter (UES) pressure (W=0.90, P=0.02), transition zone length (W=0.92, P=0.01), LES length (W=0.81, P=0.04), LES pressure (W=0.75, P=0.05), LES relaxation pressure (W=0.75, P=0.03), relative LES relaxation pressure (W=0.78, P=0.05), gastric pressure (W=0.81, P=0.04), and contraction amplitude 5cm above the LES (W=0.86, P=0.03). In conventional setting, only LES resting pressure (W=0.835, P=0.03) proved significant. In HRM tracings, concordance values for contraction wave parameters, and in conventional line tracings, LES relaxation pressure and relative relaxation pressure did not reach levels of statistical significance.

CONCLUSIONS & INFERENCES

Esophageal HRM yields reproducible results. Parameters that represent anatomic structures show better reproducibility than contraction wave parameters. The reproducibility of LES resting and relaxation pressure assessed with HRM is better than with conventional manometry and further supports the clinical use of HRM.

Effects of anti-reflux surgery on weakly acidic reflux and belching

BACKGROUND

Laparoscopic Nissen fundoplication (LNF) is the most frequently performed operation for gastro-oesophageal reflux disease (GORD). However, 12% of the patients have persistent reflux symptoms and 19% develop gas-related symptoms after LNF. Weakly acidic reflux and inability to belch have been alleged to cause these symptoms, respectively. The effect of LNF on weakly acidic reflux and (supra) gastric belching was evaluated.

METHODS

In 31 patients upper gastrointestinal endoscopy, stationary oesophageal manometry and 24-h impedance-pH monitoring off acid secretion inhibiting drugs was performed before and 6 months after primary LNF for GORD that was refractory to proton pump inhibitors. Patients filled out validated questionnaires on GERD-HRQoL before and 3, 6 and 12 months after surgery.

RESULTS

LNF reduced reflux symptoms (18.6→1.6; p = 0.015). The procedure drastically reduced the incidence (number per 24 h) of acid (76.0→1.6; p < 0.001) and weakly acidic (13.6→5.7; p = 0.001) as well as liquid (53.4→5.4; p<0.001) and mixed reflux episodes (36.3→1.9; p < 0.001). In contrast, gas reflux was reduced to lesser extent (35.6→25.7; p = 0.022). Proximal, mid-oesophageal and distal reflux were reduced to a similar extent. Persistent GORD symptoms were neither preceded by acid nor by weakly acidic reflux. The number of air swallows did not change, but the number of gastric belches (GBs) was greatly reduced (68.5→23.9; p < 0.001). Twenty-three patients had supragastric belches (SGBs), both before and after surgery, whereas eight patients had no SGBs at all. The majority of SGBs were not reflux associated and the frequency was greatly increased after LNF (20.8→46.0; p = 0.036). Reflux-associated SGBs were abolished after surgery (14.0→0.4; p < 0.001).

CONCLUSIONS

LNF similarly controls acid and weakly acidic reflux, but gas reflux is reduced to lesser extent. Persistent reflux symptoms are neither caused by acid nor by weakly acidic reflux. LNF alters the belching pattern by reducing GBs (air venting from stomach) and increasing SGBs (no air venting from stomach). This explains the increase in belching experienced by some patients after LNF, despite the reduction in gastric belching. It can be hypothesised that the reduction in GBs after LNF incites patients to increase SGBs in a futile attempt to vent air from the stomach.

Review article: the clinical relevance of transient lower oesophageal sphincter relaxations in gastro-oesophageal reflux disease

BACKGROUND

Transient lower oesophageal sphincter relaxations (TLOSR) are considered the physiological mechanism that enables venting of gas from the stomach and appear as sphincter relaxations that are not induced by swallowing. It has become increasingly clear that most reflux episodes occur during TLOSRs and therefore play a key role in gastro-oesophageal reflux disease (GERD).

AIM

To describe the current knowledge about TLOSRs and its clinical implications.

METHODS

Search of the literature published in English using the PubMed database and relevant abstracts presented at international conventions.

RESULTS

Several factors influence the rate of TLOSRs including anti-reflux surgery, meal, body position, nutrition, lifestyle and a wide array of neurotransmitters. Ongoing insights in the neurotransmitters responsible for the modulation of TLOSRs, as well as the neural pathways involved in TLOSR induction, have lead to novel therapeutic targets. These therapeutic targets can serve as an add-on therapy in patients with an unsatisfactory response to proton pump inhibitor by inhibiting TLOSRs and its associated reflux events. However, the TLOSR-inhibiting drugs that are currently available still have significant side effects.

CONCLUSION

It is likely that in the future, selected GERD patients may benefit from transient lower oesophageal sphincter relaxation inhibition when compounds are found without significant side effects.

Computer analysis of 24-h esophageal impedance signals

OBJECTIVE

To assess the accuracy of newly developed software for detection of gastro-esophageal reflux episodes in ambulatory 24-h impedance tracings. MATERIAL AND METHODS. 24-h esophageal impedance recordings obtained from 60 consecutive patients with reflux symptoms were used in this study. The impedance tracings of the first 10 consecutive patients were analyzed manually by three investigators. Liquid-containing reflux episodes and their proximal extent were scored. A consensus between the three investigators was used as a gold standard. Computer analysis using dedicated software was performed, and the results were compared with the results of the consensus agreement. In addition, in order to assess the accuracy of symptom association analysis 24-h impedance tracings of all 60 patients were analyzed both manually by one investigator and using computer software. The number of reflux episodes and the results of symptom association analysis obtained by the human and computer analysis software were compared.

RESULTS

The consensus meeting resulted in a total of 625 reflux episodes. The mean sensitivity and the percentage of true-positives of analysis by individual investigators was 89±1% and 94±1%, respectively. Automated analysis had a sensitivity of 73±4% and a proportion of true-positive reflux episodes of 62±8%. Symptom association analysis performed by the computer and a human observer showed concordant results in 83% of the patients.

CONCLUSIONS

Although not as good as manual analysis by experts, computer analysis can be a helpful tool to identify reflux episodes and to assess the relationship between reflux episodes and symptoms.

Case report: achalasia-like dysmotility secondary to oesophageal involvement of sarcoidosis

We present a case of a patient with sarcoidosis and who subsequently developed dysphagia for solids, and some difficulty in swallowing liquids. High-resolution manometry of the oesophagus showed absent peristalsis in the oesophageal body and incomplete relaxation of the lower oesophageal sphincter. The diagnosis of sarcoidosis with oesophageal involvement was made and treatment with prednisolone 30 mg OD initiated. The patient improved symptomatically and high-resolution manometry was repeated showing complete recovery of oesophageal peristalsis and a deeper relaxation of the lower oesophageal sphincter. This is thus the first description of high-resolution manometry in sarcoidosis-induced changes of the oesophagus and of the effect treatment has on these motility changes. Oesophageal involvement of sarcoidosis is extremely rare and only a few cases have been reported. The symptoms and manometric pattern of this disorder mimics that of achalasia. However, we show that treatment with prednisolone results in a completely disappearance of the symptoms of dysphagia and subsequently lead to a large improvement of oesophageal motility.

Impact of symptom-reflux association analysis on long-term outcome after Nissen fundoplication

BACKGROUND

A positive symptom association probability (SAP) is regarded as an important selection criterion for antireflux surgery by many physicians. However, no data corroborate the relationship between symptom-reflux association and outcome, nor is it clear what impact a negative SAP has on the outcome of antireflux surgery in patients with abnormal oesophageal acid exposure. This study compared long-term outcomes of Nissen fundoplication in patients with a negative versus positive SAP.

METHODS

Five-year outcome of Nissen fundoplication in patients with proton-pump inhibitor (PPI)-refractory reflux and pathological acid exposure was compared between those with (SAP+, 109) and without (SAP-, 29 patients) a positive symptom association. Symptoms, quality of life (QoL), PPI use, endoscopic findings, manometry and acid exposure were evaluated.

RESULTS

At 5 years' follow-up, relief of reflux symptoms (95 versus 87 per cent), reduction in PPI use (80 to 25 per cent versus 85 to 14 per cent; P < 0·050) and improvement in QoL were similar in the SAP- and SAP+ groups. Reduction in acid exposure time (13·4 to 1·6 per cent versus 11·1 to 0·2 per cent of total time; P < 0·010), improvement in oesophagitis (44 to 6 per cent versus 61 to 13 per cent; P < 0·050) and increase in lower oesophageal sphincter pressure were also comparable.

CONCLUSION

The subjective and objective outcomes of fundoplication in patients with pathological acid exposure are comparable among those with a positive and negative SAP. Patients with pathological acid exposure and a negative SAP can also benefit from antireflux surgery.

Long-term outcome of Nissen fundoplication in non-erosive and erosive gastro-oesophageal reflux disease

BACKGROUND

Non-erosive (NERD) and erosive (ERD) gastro-oesophageal reflux disease (GORD) show similar severity of symptoms and impact on quality of life (QoL). Prospective data on long-term outcomes of antireflux surgery in NERD are lacking.

METHODS

Subjective and objective 5-year outcomes of Nissen fundoplication were compared in 96 patients with NERD and 117 with ERD, operated on for proton-pump inhibitor (PPI)-refractory GORD.

RESULTS

Preoperative and postoperative QoL, PPI use, acid exposure time, symptom-reflux correlation, lower oesophageal sphincter (LOS) pressure and reoperation rates were similar in the two groups. At 5 years, relief of reflux symptoms was similar (NERD 89 per cent versus ERD 96 per cent), PPI use showed a similar reduction (82 to 21 per cent versus 81 to 15 per cent respectively; both P < 0.001) and QoL score improved equally (50.3 to 65.2 (P < 0.001) versus 52.0 to 60.7 (P = 0.016)). Five patients with NERD developed erosions after surgery; oesophagitis healed in 87 per cent of patients with ERD. Reduction in total acid exposure time (NERD 12.7 to 2.0 per cent versus ERD 13.8 to 2.9 per cent; both P < 0.001) and increase in LOS pressure (1.3 to 1.8 kPa versus 1.2 to 1.8 kPa; both P < 0.001) were similar. The reintervention rate was comparable (NERD 15 per cent versus ERD 12.8 per cent).

CONCLUSION

Patients with PPI-refractory NERD and ERD benefit equally from Nissen fundoplication. The absence of mucosal lesions on endoscopy in patients with proven PPI-refractory reflux disease is not a reason to refrain from antireflux surgery.

New therapies for gastroesophageal reflux disease

It is estimated that approximately 30% of the GERD patients is not satisfied about the effect of proton pump inhibitors on their symptoms. Esophageal hypersensitivity, persistent non-acid reflux and incomplete acid suppression all can play a role in the pathogenesis of persistent GERD symptoms. More powerful inhibitors of the proton pump are now being developed, resulting in a more prolonged and profound acid suppression. New prokinetics and inhibitors of transient lower esophageal sphincter relaxations (TLESRs) can potentially reduce both acid and non-acid reflux and drugs that reduce hypersensitivity are possibly helpful for the treatment of non-erosive reflux disease. Whether these drugs will make it to the markets will mainly depend on their side effect profile and their ability to have an additional beneficial effect over the current gold standard therapy as it likely that a new antireflux drug will be used in combination with proton pump inhibitors. Over the last decade various endoscopic antireflux techniques have been introduced, most of them have been withdrawn soon after introduction due to lack of effect or after the occurrence of severe side-effects. Several endoluminal plication techniques and endoluminal radiofrequency ablation therapy are still available and being evaluated in research centres but more data on safety and efficacy is required before a more widespread use can be advised.

Excessive belching and aerophagia: two different disorders

Belching is physiological venting of excessive gastric air. Excessive and bothersome belching is a common symptom, which is often seen in patients with functional dyspepsia and gastroesophageal reflux disease. Other symptoms are usually predominant. However, a small group of patients complain of isolated excessive belching, with a frequency of several belches per minute. In these patients, the eructated air does not originate from the stomach but is sucked or injected in the esophagus from the pharynx and expelled immediately afterward in oral direction. This behavior is called supragastric belching because the air does not originate from the stomach and does not reach the stomach either. Excessive belching can be treated by speech therapy or behavior therapy. The term aerophagia should be reserved for those patients where there is evidence that they swallow air too frequently and in too large quantities. These patients have excessive amounts of intestinal gas visualized on a plain abdominal radiogram and their primary symptoms are bloating and abdominal distension and they belch only to a lesser degree. Aerophagia and excessive supragastric belching are thus two distinct disorders.

Effect of proximal gastric volume on hiatal hernia

BACKGROUND

Spatial separation of the diaphragm and the lower esophageal sphincter (LES) occurs frequently and intermittently in patients with a sliding hiatus hernia and favors gastro-esophageal reflux. This can be studied with high-resolution manometry. Although fundic accommodation is associated with a lower basal LES pressure, its effect on esophagogastric junction configuration and hiatal hernia is unknown. Therefore, the aim of this study was to investigate the relationship between proximal gastric volume, the presence of a hiatal hernia profile and acid reflux.

METHODS

Twenty gastro-esophageal reflux disease (GERD) patients were studied and compared to 20 healthy controls. High-resolution manometry and pH recording were performed for 1 h before and 2 h following meal ingestion (500 mL per 300 kcal). Volume of the proximal stomach was assessed with three-dimensional ultrasonography before and every 15 min after meal ingestion.

KEY RESULTS

During fasting, the hernia profile [2 separate high-pressure zones (HPZs) at manometry] was present for 31.9 +/- 4.9 min h(-1) (53.2%) in GERD patients, and 8.7 +/- 3.3 min h(-1) (14.5%) in controls (P < 0.001). In GERD patients, the presence of hernia profile decreased during the first postprandial hour to 15.9 +/- 4.2 min h(-1), 26.5%, P < 0.01 whilst this phenomenon was not observed in controls. The rate of transition between the two profiles was 5.7 +/- 1.1 per hour in GERD patients and 2.5 +/- 1.0 per hour in controls (P < 0.001). The pre and postprandial acid reflux rate in GERD patients during the hernia profile (6.4 +/- 1.1 per hour and 18.4 +/- 4.3 per hour respectively) was significantly higher than during reduced hernia (2.1 +/- 0.6 per hour; P < 0.05 and 3.8 +/- 0.9 per hour; P < 0.05). A similar difference was found in controls. Furthermore, an inverse correlation was found between fundic volume and the time the hernia profile was present (r = -0.45; P < 0.05) in GERD patients, but not in controls.

CONCLUSIONS & INFERENCES

(i) In GERD patients a postprandial increase in proximal gastric volume is accompanied by a decrease in hernia prevalence, which can be explained by a reduction of the intra-thoracic part of the stomach. (ii) A temporal hernia profile also occurs in healthy subjects. (iii) During the hernia profile, acid reflux is more prevalent, especially after meal ingestion.

Speech therapy in patients with excessive supragastric belching--a pilot study

In patients whose main symptom is excessive belching, supragastric belching appears to be the predominant mechanism. This belch pattern is characterized by a rapid influx of air into the oesophagus, immediately followed by rapid air expulsion. The rate at which supragastric belching occurs is influenced by attention and distraction, suggesting a behavioural disorder and speech therapy may be of benefit to these patients. In 17 consecutive patients with excessive belching, concurrent impedance monitoring and high-resolution manometry were performed to ascertain the mechanism of belching. Patients with supragastric belches were referred to a speech therapist, who was familiar with the concept of supragastric belching. Before and after treatment by the speech therapist, patients filled out a VAS scale regarding the severity of their symptoms. In all patients, supragastric belches were identified with impedance monitoring. Eleven patients were referred to a speech therapist, six patients were not able or willing to undergo repetitive treatments. Eleven patients completed treatment by the speech therapist consisting of 10 (8-10) sessions. Overall, the VAS scales showed a significant improvement of the severity of symptoms (P < 0.05). Six of the 11 patients reported a large decrease (>30%) in their symptoms and four patients reported a modest decrease (<30%). In one patient, the VAS scores indicated an increase in symptoms. Speech therapy performed by a well-informed speech pathologist leads to a significant symptom reduction in patients with excessive supragastric belching. This is the first study indicating benefit of a treatment for excessive belching.

Aerophagia: excessive air swallowing demonstrated by esophageal impedance monitoring

BACKGROUND & AIMS

Patients with aerophagia suffer from the presence of an excessive volume of intestinal gas, which is thought to result from excessive air ingestion. However, this has not been shown thus far. The aim of this study was therefore to assess swallowing and air swallowing frequencies in patients with suspected aerophagia.

METHODS

Ambulatory 24-hour pH-impedance monitoring was performed in patients in whom excessive amounts of intestinal gas were visualized on plain abdominal radiograms. All patients had symptoms of bloating, abdominal distention, flatulence, or excessive belching. Reflux parameters and the number of swallows and air swallows were assessed.

RESULTS

The most common symptoms were bloating, abdominal distention, and constipation. Only 3 patients reported excessive belching and 1 patient reported flatulence as their predominant symptom. During the 24-hour measurement, patients showed high incidences of air swallows (521 +/- 63) and gastric belches (126 +/- 37). Patients had normal swallowing frequency (741 +/- 71).

CONCLUSIONS

This study presents objective parameters that confirm the existence of excessive air swallowing or aerophagia using esophageal impedance monitoring.

Does acute psychological stress increase perception of oesophageal acid?

Gastro-oesophageal reflux disease (GORD) patients often report an increase in their reflux symptoms during stressful situations. The aim of this study was to assess the influence of acute psychological stress on oesophageal acid perception. In 15 healthy volunteers and 10 GORD patients with a positive symptom-reflux association an oesophageal acid perfusion test was performed, once with and once without the presence of an acute psychological stressor (IQ test). The order of the measurements was randomized. The time from onset of the acid infusion to first acid perception, discomfort and pain was noted. Blood pressure was measured to assess the effect of the stress task. In healthy volunteers, the time to first perception (control task: 617 +/- 174 s vs stress task: 561 +/- 162 s), discomfort (control task: 969 +/- 158 s vs stress task: 940 +/- 151 s) or pain (control task: 1393 +/- 122 s vs stress task: 1366 +/- 121 s) did not differ significantly between both measurements. In GORD patients, no significant differences between both measurements were found either in time to first perception (control task: 63 +/- 26 s vs stress task: 43 +/- 15 s), discomfort (control task: 153 +/- 44 s vs stress task: 249 +/- 62 s) or pain (control task: 558 +/- 139 s vs stress task: 633 +/- 118 s). Systolic blood pressure rose significantly during the stress task in both the healthy volunteers (6 +/- 1 mmHg) and the GORD patients (9 +/- 2 mmHg). Neither in the healthy volunteers nor in the GORD patients, the acute psychological stress induced by an IQ test increased oesophageal acid perception. The observed increase in systolic blood pressure shows that the experimental stressors were effective.

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.

Lesogaberan, a GABA(B) agonist for the potential treatment of gastroesophageal reflux disease

Lesogaberan, under development by AstraZeneca plc, is a GABA(B) agonist for the potential treatment of gastroesophageal reflux disease (GERD). In vitro, lesogaberan was an efficient GABA(B) agonist and was taken up by GABA(B) receptors, thereby maintaining low extracellular levels of lesogaberan in the CNS and avoiding the serious CNS side-effect profile of the GABA(B) agonist baclofen. In phase I and IIa clinical trials, lesogaberan treatment was well tolerated, and resulted in a substantial reduction in reflux episodes by decreasing the frequency of transient lower esophageal sphincter relaxations. At the time of publication, a phase IIa trial was ongoing in patients with GERD that was partially refractive to standard proton pump inhibitor (PPI) therapy. Lesogaberan may have potential to be used as an add-on therapy to PPIs. However, the safety, efficacy and advantages of lesogaberan compared with existing therapies remain to be established in phase IIb and III trials.

The preoperative reflux pattern as prognostic indicator for long-term outcome after Nissen fundoplication

OBJECTIVES

We set out to investigate the impact of the preoperative reflux pattern on long-term outcome after Nissen fundoplication. Recent studies disagree on whether patients with pathological upright reflux should be discouraged from undergoing surgery.

METHODS

A total of 338 patients underwent Nissen fundoplication. Of these, 234 of 289 patients had pathological acid exposure on preoperative 24-h esophageal pH monitoring and their reflux was classified as pathological upright (n=81), supine (n=55), or bipositional (n=98). Clinical outcomes and results of endoscopy, manometry, and 24-h pH monitoring were compared before surgery, and at 3 months and 5 years after surgery.

RESULTS

Patients with pathological upright and supine reflux had similar preoperative reflux parameters. In patients with pathological bipositional reflux, however, preoperative total acid exposure was higher than that in patients with upright or supine reflux (18.3% vs. 10.7 and 7.5%; P<0.001 and P<0.001). Prevalence of esophagitis was higher in patients with bipositional reflux than in those with upright reflux, both before (64.0 vs. 45.6%; P=0.035) and 3 months after surgery (16.0 vs. 3.5%; P=0.018). Before surgery, mean lower esophageal sphincter (LES) pressure was lower compared with the upright and supine reflux groups (1.0 vs. 1.5 and 1.6 kPa; P=0.007 and 0.005, respectively). The increase in quality of life, reduction of symptoms, use of acid-suppressing drugs, total acid exposure, and esophagitis were independent of reflux pattern at 3 months and 5 years after surgery (all P<0.05). Prevalence of recurrent pathological acid exposure was higher in the bipositional group than in the upright group (40.9 vs. 10.7%; P=0.013). Surgical reintervention was significantly more common in bipositional reflux patients (20.0 vs. 8.9% for upright and 4.1% for supine).

CONCLUSIONS

All three pathological reflux patterns respond favorably to Nissen fundoplication in the long term. Patients with pathological bipositional reflux, however, suffer from more severe disease with higher chance of recurrence and reoperation.

High-resolution manometry in clinical practice: utilizing pressure topography to classify oesophageal motility abnormalities

High-resolution manometry capable of pressure monitoring from the pharynx to the stomach together with pressure topography plotting represents an unquestionable evolution in oesophageal manometry. However, with this advanced technology come challenges and one of those is devising the optimal scheme to apply high-resolution oesophageal pressure topography (HROPT) to the clinical evaluation of patients. The first iteration of the Chicago classification was based on a systematic analysis of motility patterns in 75 control subjects and 400 consecutive patients. This review summarizes the analysis process as it has evolved. Individual swallows are analysed in a stepwise fashion for the morphology of the oesophagogastric junction (OGJ), the extent of OGJ relaxation, the propagation velocity of peristalsis, the vigour of the peristaltic contraction, and abnormalities of intrabolus pressure utilizing metrics that have now been customized to HROPT. These results are then synthesized into a comprehensive diagnosis that, although based on conventional manometry criteria, is also customized to HROPT measures. The resultant classification objectifies the identification of three unique subtypes of achalasia. Additionally, it provides enhanced detail in the description of distal oesophageal spasm, nutcracker oesophagus subtypes, and OGJ obstruction. It is our expectation that modification of this classification scheme will continue to occur and this should further clarify the utility of pressure topography plotting in assessing oesophageal motility disorders.

Relationship between gastro-oesophageal reflux pattern and severity of mucosal damage

The aim of the study is to compare the characteristics of reflux episodes in controls and in patients with various degrees of oesophagitis and Barrett's oesophagus. Ambulatory 24-h impedance-pH tracings were analysed from healthy volunteers, patients with non-erosive reflux disease (NERD), patients with grade A oesophagitis, grade B oesophagitis, grade C or D oesophagitis and patients with a short segment (<2 cm) of Barrett's metaplasia. The number of acid and weakly acidic reflux episodes increased from 25.9 +/- 3.9 to 17.9 +/- 1.5 in the controls, 39.9 +/- 6.3 to 33.4 +/- 5.7 in the patients with NERD, 46.6 +/- 6.2 to 40.4 +/- 9.2 in grade A, 68.2 +/- 9.2 to 49.2 +/- 12.3 in grade B, 79.8 +/- 15.6 to 47.4 +/- 4.6 in grade C/D and 75.1 +/- 7.9 to 37.3 +/- 8.5 in the patients with Barrett. The proportion of reflux episodes that is acidic or alkaline was similar all groups. Comparison with normal values revealed that none of the controls, 40% of the patients with NERD, 50% of the patients with grade A, 80% of the patients with grade B and all patients with grade C/D or Barrett's oesophagus had an abnormally high total number of reflux episodes. In the patients with severe oesophagitis a significantly higher percentage of reflux episodes reached the proximal oesophagus (43.8%) compared to the patients with Barrett's oesophagus (19.2%). With increasing degrees of oesophagitis, patients have more reflux episodes but a large overlap between the groups exists making comparison with normal values of limited relevance. In patients with Barrett's oesophagus fewer reflux episodes reach the proximal oesophagus which might explain their low sensitivity to reflux.

Involvement of afferent neurons in the pathogenesis of endotoxin-induced ileus in mice: role of CGRP and TRPV1 receptors

Activation of neuronal reflex pathways by inflammatory mediators is postulated as an important pathogenic mechanism in postoperative ileus. In this study, we investigated the involvement of afferent neurons and more specifically the role of the transient receptor potential vanilloid receptor type 1 (TRPV1) and calcitonin gene-related peptide (CGRP) in endotoxin-induced motility disturbances in mice. Mice were injected with either lipopolysaccharides (LPS) or saline (control) and pre-treated with hexamethonium (blocker of neuronal transmission), capsaicin (neurotoxin), CGRP 8-37 (CGRP antagonist) or BCTC (TRPV1 receptor antagonist). We measured gastric emptying and intestinal transit of Evans blue next to rectal temperature and a global sickness behaviour scale. In vehicle-treated mice, LPS significantly delayed gastric emptying, small intestinal transit and rectal temperature while the sickness behaviour scale was increased. Hexamethonium, capsaicin, CGRP8-37 and BCTC all reversed the endotoxin-induced delay in gastric emptying and significantly reduced the delay in intestinal transit without effect on the endotoxin-induced decrease in rectal temperature and increase in sickness behaviour scale. Our findings provide evidence for the involvement of afferent nerves in the pathogenesis of endotoxin-induced motility disturbances in mice mediated via CGRP and TRPV1 receptors. Blockade of CGRP and TRPV1 receptors may offer a novel strategy for the treatment of endotoxin-induced ileus.

Reliability of oesophageal pH recording for the detection of gastro-oesophageal reflux

OBJECTIVE

Despite the new gold standard oesophageal impedance monitoring, pH monitoring is still used frequently for detection of gastro-oesophageal reflux (GOR). Besides drops in pH from above to below pH4, drops of > or =1 unit are also used as a marker for GOR. In this study the objective was to investigate the accuracy of drops in pH for detection of GOR, using impedance monitoring as the gold standard.

MATERIAL AND METHODS

Nineteen GORD patients (9 M, 55+/-11 years) underwent combined 24-h pH-impedance recording off acid-suppressive therapy. All drops in pH > or =0.5 pH units, with a duration > or =4 s, reaching the nadir pH within 5 s after onset were included. Reflux events detected with impedance monitoring were taken as the reference.

RESULTS

In total, 2221 drops in pH were found; 47% were acid (nadir pH <4), 47% weakly acidic (nadir pH between pH7 and 4) and 5% were superimposed (pH drop starting below pH4). The sensitivities of acid, weakly acidic and superimposed pH drops > or =1 were 91%, 28%, 24%, respectively, and the percentages of false-positive reflux episodes were 20, 56 and 54, respectively. Acid reflux with a cut-off > or =0.5 and < or =3.3 had a moderate-to-good sensitivity (94-70%) and low false-positive percentages (23-13%). In contrast, weakly acidic and superimposed reflux showed greater false-positive than true-positive percentages for all cut-off values.

CONCLUSIONS

Compared to impedance monitoring, detection of reflux with pH monitoring is clearly inferior. When drops in pH > or =1 are used irrespective of nadir pH as an indicator of reflux episodes, the number of reflux episodes is overestimated. Decreases from above to below 4 with cut-offs between > or =0.5 and < or =3.3 are the most indicative of true reflux episodes.

Increased swallowing frequency in GORD is likely to be caused by perception of reflux episodes

Patients with gastro-oesophageal reflux disease (GORD) swallow air more frequently and have more gas-containing reflux episodes than healthy controls. One explanation for this phenomenon may be that GORD patients primarily swallow more frequently and, as a consequence, have more swallow- or transient lower oesophageal sphincter relaxation-associated reflux episodes. Another explanation may be that GORD patients swallow more often in response to perception of reflux episodes. The aim of this study was to differentiate between these two possible mechanisms. In 34 patients with typical reflux symptoms oesophageal 24-h pH-impedance monitoring was performed twice, once off and once on proton pump inhibitor (PPI) therapy. The number of reflux episodes and number of swallows and air swallows was evaluated. The symptom association probability (SAP) was used to distinguish patients with a good relationship between symptoms and reflux episodes (SAP+) from those who had not (SAP-). In both the SAP+ (n = 21) as SAP- patients (n = 13), the acid exposure time decreased during PPI therapy. In the SAP+ patients, the number of swallows decreased on PPI (829 +/- 85 off vs 701 +/- 79 on PPI, P < 0.05), whereas in the SAP- patients, the incidence of swallows (802 +/- 93 off vs 814 +/- 69 on PPI, P = NS) was not influenced by the PPI therapy. PPI therapy reduces the number of swallows in patients with a positive SAP, but not in those with a negative SAP. This finding supports the hypothesis that the increased incidence of swallows in GORD is brought about by responses to perceived reflux events.

Esophageal motility testing: impedance-based transit measurement and high-resolution manometry

Esophageal function tests are widely used, not only to obtain insight into esophageal physiology and pathophysiology in a research setting, but also to diagnose esophageal motor disorders in patients with symptoms such as dysphagia and chest pain. While esophageal function testing has long been considered almost synonymous with manometry, recently new techniques such as impedance measurement and high-resolution manometry have emerged. With impedance monitoring the transit of a bolus through the esophagus can be studied without the use of ionizing radiation. High-resolution manometry offers a highly detailed and comprehensive view of esophageal pressure patterns. Multichannel high resolution manometry with color plotting facilitates positioning of the catheter and interpretation of the tracings. In this article the development, clinical usefulness, and indications of these new tests are discussed.

[Therapy resistance of gastro-oesophageal reflux symptoms: acid reflux, non-acid reflux or no reflux]

The introduction of proton pump inhibitors (PPIs) was a huge step forward in the treatment of gastric acid-related disorders such as reflux disease and gastric ulcers. Despite the strong effectiveness of PPIs, in a small number of patients reflux symptoms are not adequately relieved by these drugs. The amount of acid inhibition that can be achieved using a PPI depends on a number of different factors, such as Helicobacter pylori infection, genetic variation in metabolizing enzymes, and lack of compliance. Nocturnal gastric acid breakthrough does not appear to be important in the pathogenesis of therapy-resistant reflux symptoms. Not all reflux from the stomach into the oesophagus appears to be acidic. Episodes of non-acid reflux may also elicit typical reflux symptoms. This can be established by impedance measurements of the oesophagus. However, most patients whose symptoms do not respond satisfactorily to PPI therapy appear not to have reflux disease but instead be suffering from other conditions such as functional dyspepsia, aerophagy or rumination. Careful history-taking is pivotal in patients with reflux symptoms and should always precede additional investigations such as upper endoscopy and if necessary 24-hour reflux monitoring.

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.