Do bile acids reflux into the esophagus? A study in normal subjects and patients with gastroesophageal reflux disease

Comparisons of symptoms reported by elderly and non-elderly patients with GERD

BACKGROUND

The characteristics of symptoms reported by elderly patients with gastroesophageal reflux disease (GERD) have not been fully investigated. We performed this study to clarify these characteristics in elderly patients with GERD.

METHODS

The study subjects were 340 Japanese patients with symptoms of heartburn and/or acid regurgitation. All patients were investigated by upper gastrointestinal endoscopy, and were asked about the presence of atypical GERD symptoms, such as an epigastric burning sensation, epigastralgia, epigastric discomfort, and abdominal fullness, as well as the time of day when bothersome symptoms occurred.

RESULTS

Of the 340 patients, 161 were elderly (≥65 years old) and 179 were non-elderly (age <65 years). There were 158 patients without esophageal mucosal breaks, 147 with low-grade reflux esophagitis (RE; Los Angeles classification grade A or B), and 35 with high-grade reflux esophagitis (LA grade C or D). Elderly patients with RE reported typical reflux symptoms at the same frequency as the non-elderly patients, whereas elderly patients without mucosal breaks reported typical symptoms more frequently than the non-elderly patients without mucosal breaks. Both elderly and non-elderly patients with different types of GERD reported that their symptoms occurred most frequently during the postprandial period.

CONCLUSION

Elderly patients with GERD tend to show typical GERD symptoms frequently at the typical post-prandial time points in a day, irrespective of the presence of esophageal mucosal breaks.

Systematic review: the role of bile acids in the pathogenesis of gastro-oesophageal reflux disease and related neoplasia

BACKGROUND

Factors other than acid may play a role in gastro-oesophageal reflux disease (GERD) and its complications.

AIM

To assessed the role of bile acids in the pathogenesis of GERD, Barrett's oesophagus and Barrett's-related neoplasia.

METHODS

We conducted a systematic review of computerised bibliographic databases for original articles involving humans or human oesophageal tissue or cells that assessed exposure to or manipulation of bile acids. Outcomes assessed included GERD symptoms; gross oesophageal injury; Barrett's oesophagus and related neoplasia; and intermediate markers of inflammation, proliferation or neoplasia.

RESULTS

Eighty-three original articles were included. In in vivo studies, bile acids concentrations were higher in the oesophageal aspirates of patients with GERD than controls, and bile acids infusions triggered GERD symptoms, especially in high concentrations or in combination with acid. In ex vivo/in vitro studies, bile acids stimulated squamous oesophageal cells and Barrett's epithelial cells to produce inflammatory mediators (e.g., IL-8 and COX-2) and caused oxidative stress, DNA damage and apoptosis. They also induced squamous cells to change their gene expression pattern to resemble intestinal-type cells and caused Barrett's cells to increase expression of intestinal-type genes.

CONCLUSIONS

In aggregate, these studies suggest that bile acids may contribute to the pathogenesis of symptoms, oesophagitis and Barrett's metaplasia with related carcinogenesis in patients with GERD. However, all study results are not uniform and substantial differences in study parameters may explain at least some of this variation.

Emerging concepts of bile reflux in the constellation of gastroesophageal reflux disease

RATIONALE

Reflux of gastric and duodenal contents in patients with gastroesophageal reflux disease (GERD) has been postulated as a major cause of complications, such as Barrett's esophagus or malignant degeneration.

FINDINGS

We present a summary of experimental, clinical, and immunohistochemical studies that show that acid and bile reflux are increased in patients who suffer from GERD, are the key factor in the pathogenesis of Barrett's esophagus, and are possibly related to the development of esophageal adenocarcinoma.

Proximal oesophagus: the added value in understanding GORD symptoms

Over the past decade, the approach to the understanding of the mechanisms involved in the aetiology of gastro-oesophageal reflux disease (GORD) symptoms has changed, and growing evidence now supports the concept that visceral hyper-sensitivity to intra-oesophageal stimuli plays a major role. Among the recent advances, one of the more consistent findings is that the contact of the refluxate, either acidic or weakly acidic, with the proximal oesophageal mucosa, is a main determinant of GORD symptoms, particularly in the large majority of patients affected by non-erosive reflux disease. The data reported in the current issue of Neurogastroenterology and Motility by Bredenoord et al., showing only a small proportion of proximal reflux in patients with Barrett's oesophagus, who are less sensitive to gastro-oesophageal reflux, further support the consistency of this finding in the pathogenesis of symptoms. In the light of these results, we shall look forward, in the management of patients, to approaches aimed at restoring the antireflux barrier, hopefully decreasing the amount of reflux and, in turn, its proximal extent.

Review article: acidity and volume of the refluxate in the genesis of gastro-oesophageal reflux disease symptoms

BACKGROUND

A number of mechanisms, other than acid reflux, may be responsible for the symptoms of gastro-oesophageal reflux disease.

AIM

To assess the importance of non-acid reflux mechanisms.

METHODS

This review is based on presentations and discussion at a workshop, where specialists in the field analysed data relating to these mechanisms.

RESULTS

Weakly acidic reflux, pH (4-7), detected with impedance-pHmetry is associated with regurgitation and atypical gastro-oesophageal reflux disease symptoms. It is not clear whether pepsin and trypsin can elicit symptoms, but bile can elicit heartburn. The magnitude of reflux-induced oesophageal distension can be determined by high frequency ultrasonography and is not reduced by proton pump inhibition, suggesting that persisting symptoms 'on' a proton pump inhibitor may still be due to oesophageal distension by non-acidic reflux. Exaggerated longitudinal muscle contraction can induce non-acid-related heartburn. Preliminary studies showed a positive effect of baclofen, surgery or endoscopic procedures to reduce weakly acidic reflux.

CONCLUSION

Mechanisms other than acid reflux are involved in some of the symptoms of gastro-oesophageal reflux disease. Controlled outcome studies are needed to clarify their roles and the indications for antireflux procedures in patients with persistent symptoms whilst 'on' a proton pump inhibitor.

Bile acids and Barrett's oesophagus: a sine qua non or coincidence?

BACKGROUND

Barrett's oesophagus (BO), a premalignant condition associated with the development of oesophageal adenocarcinoma (OAC), is thought to be a consequence of chronic duodeno-gastro-oesophageal reflux. Of the refluxates, bile acids, either alone or in combination with acid, are probably the most important.

METHODS

Analysis of the literature on the role played by bile acids in inducing BO and/or progression to OAC.

RESULTS

Combined pH and Bilitec 2000 (as a measure of bile reflux) monitoring and oesophageal aspiration studies in humans suggest a combined role for bile acids, particularly taurine conjugated bile acids, in causing oesophageal mucosal injury. Evidence from animal models has demonstrated that duodenal juice alone is also able to induce BO and/or OAC. Likewise, ex vivo studies with biopsies from BO patients show that increased proliferation and cyclo-oxygenase-2 expression are present after a pulsed exposure to acid or conjugated bile acids, but not if acid and bile acids are combined. Proton-pump inhibitors (PPIs) have been shown to decrease the biliary component of the refluxate. There is some evidence that PPIs are able to reduce neoplastic progression in BO. On the other hand, chronic PPIs can also stimulate bacterial overgrowth, which can result in increased production of secondary bile acids, particularly deoxycholic acid, in the stomach. Deoxycholic acid has been demonstrated to have a tumour-promoting capacity.

CONCLUSIONS

It is unknown what factors of the refluxate (acid and/or bile) induce BO and/or promote carcinogenesis, but there is evidence that secondary bile acids play a role. A better understanding of the molecular steps involved in the induction of BO, and the role of bile acids herein, may identify targets at which preventive therapies can be directed.

Le reflux biliaire duodéno-gastrique et gastro-œsophagien

This study reviews current data regarding duodenogastric and gastroesophageal bile reflux-pathophysiology, clinical presentation, methods of diagnosis (namely, 24-hour intraluminal bile monitoring) and therapeutic management. Duodenogastric reflux (DGR) consists of retrograde passage of alkaline duodenal contents into the stomach; it may occur due to antroduodenal motility disorder (primary DGR) or may arise following surgical alteration of gastoduodenal anatomy or because of biliary pathology (secondary DGR). Pathologic DGR may generate symptoms of epigastric pain, nausea, and bilious vomiting. In patients with concomitant gastroesophageal reflux, the backwash of duodenal content into the lower esophagus can cause mixed (alkaline and acid) reflux esophagitis, and lead, in turn, to esophageal mucosal damage such as Barrett's metaplasia and adenocarcinoma. The treatment of DGR is difficult, non-specific, and relatively ineffective in controlling symptoms. Proton pump inhibitors decrease the upstream effects of DGR on the esophagus by decreasing the volume of secretions; promotility agents diminish gastric exposure to duodenal secretions by improving gastric emptying. In patients with severe reflux resistant to medical therapy, a duodenal diversion operation such as the duodenal switch procedure may be indicated.

Effect of topical esophageal acidification on salivary secretion: identification of the mechanism of action

BACKGROUND

In past studies, investigators have reported that the salivary glands respond to esophageal acidification by increased salivary secretion and termed this response the 'esophago-salivary response'. The existence, however, of such a reflex was but a speculation because the verification of its mechanism could not be traced in the literature. In the current study, the hypothesis that the salivary glands' response to esophageal acidification is a reflex was investigated.

METHODS

In 15 healthy volunteers (nine men, six women, age 32.3 +/- 4.2 years) the saliva of the four salivary glands was collected by intubation after individual esophageal perfusion with normal saline and 100 mmol HCl. The test was repeated after each of the lower esophagus and the salivary glands had been separately anesthetized. The latency was calculated.

RESULTS

The mean basal volume of saliva was 62.7 +/- 6.4 mL/60 min. This volume did not show a significant change (P > 0.05) on esophageal saline instillation, whereas acid perfusion effected a significant increase (P < 0.01). The mean latency was 12.4 +/- 2.7 s. Esophageal acid perfusion after lower esophageal anesthetization did not produce a significant change in salivary volume; similar results were obtained on repetition of the test after anesthetization of salivary glands. When saline was used instead of lidocaine in the lower esophagus or salivary glands, the salivary glands' response was similar to that without saline perfusion.

CONCLUSION

Esophageal acidification effected an increase of secreted saliva which clears the esophagus of the refluxed acid. Increased salivation on esophageal acidification is suggested to be a reflex and is mediated through the 'esophago-salivary' reflex. This reflex might be of diagnostic significance in the investigation of reflux esophagitis, a point that requires further study.

Gastric fullness, physical activity, and proximal extent of gastroesophageal reflux

OBJECTIVES

Proximal extent of gastroesophageal reflux (PER) is relevant for symptoms in GERD patients. It has been suggested that PER is determined by the volume of the refluxate that, in turn, might depend on the degree of gastric fullness. Abdominal straining, during ambulation, increases the likelihood of gastroesophageal reflux. We assessed the influence of gastric fullness and ambulation on proximal extent of reflux.

METHODS

PER was assessed in 37 patients with GERD undergoing ambulatory pH impedance monitoring. In 14 controls and 19 GERD patients, esophageal pH impedance and gastric emptying were also studied simultaneously in stationary conditions. We compared PER during fasting, early postprandial (before half emptying), and late postprandial periods in ambulatory and stationary conditions.

RESULTS

More reflux episodes reached the proximal esophagus in the postprandial period compared to fasting (60%+/-4 vs 29%+/-3, p<0.05). In stationary conditions, early postprandial reflux reached higher proximal extent than late postprandial reflux (15+/-3% vs 8+/-4%, p<0.05). The proportion of reflux events reaching the proximal esophagus was significantly higher in ambulatory than in stationary conditions (29+/-5% vs 15+/-3%, p<0.05).

CONCLUSION

Compared to fasting, reflux episodes occurring after the meals are more likely to reach higher proximal extent, particularly so during the early postprandial period. The highest proportion of postprandial proximal reflux occurred in ambulatory condition. These findings suggest that reducing meal volumes and early postprandial physical activity might contribute to decrease proximal extent of reflux and postprandial GERD symptoms.

Early and late results of the acid suppression and duodenal diversion operation in patients with barrett's esophagus: analysis of 210 cases

The usual surgical treatment for patients with Barrett's esophagus (BE) is a classic Nissen fundoplication or posterior gastropexy with cardial calibration. However, some surgical reports as well as our experience suggest that the rate of failure of the Nissen fundoplication or Hill's posterior gastropexy in patients with BE is significantly higher than in those with reflux esophagitis without BE, probably due in part to the persistence of duodenal reflux into the esophagus. Our aim was to determine the late subjective and objective results of an operation consisting in "acid suppression" (vagotomy-partial gastrectomy) and "duodenal diversion" (Roux-en-Y anastomosis) as a primary surgical procedure for patients with BE. Altogether, 210 patients were subjected to this technique. It consisted in a primary operation in 142 patients and revision surgery in 68. They underwent complete clinical, radiologic, endoscopic, histologic, and manometric studies. In some cases 24-hour pH studies, Bilitec studies, gastric emptying, and gastric acid secretion evaluations were performed. There were two deaths (0.95%), and postoperative morbidity was low (5.3%). The late mean follow-up (58 months) for 146 patients who completed a follow-up longer than 24 months showed Visick I and II grades in 91.1% of the cases. In 14.9% of the cases 24-hour pH monitoring showed excessive acid reflux 1 year after surgery. No dysplasia or adenocarcinoma has appeared up to now. Functional studies showed significant alleviation of lower esophageal sphincter (LES) incompetence, with abolition of duodenal reflux into the esophagus. Gastric emptying of solids was normal, and basal and peak gastric acid output remained at a low level 8 to 10 years after surgery. In patients with BE, with severe damage of the LES and esophageal peristalsis, the "suppression diversion" operation completely abolishes the reflux of injurious components of the refluxate and improves sphincter competence. This effect is permanent and avoids the appearance of dysplasia or adenocarcinoma.

Roux-en-Y long limb diversion as the first option for patients who have Barrett's esophagus

In summary, vagotomy plus antrectomy and the Roux-en-Y procedure is based on the following points: (a) patients who have BE show several foregut abnormalities, including incompetent lower esophageal sphincter, impairment in the esophageal clearance, severe gastroesophageal acid reflux, and frequent duodenoesophageal reflux; (b) late results of classic antireflux procedure in BE are poor with a high recurrence rate owing to a progressive loosening of the wrap; (c) the esophageal damage is produced by the injurious component of the refluxate; and (d) among patients who underwent classic antireflux surgery, a certain proportion developed dysplasia or even adenocarcinoma in the follow-up. The authors have observed that the simple correction of the valve is not enough in many cases, because it does not abolish the gastroesophageal reflux but only diminishes it. In patients who have BE and therefore have impaired esophageal clearance, few reflux episodes can maintain or even induce more damage. With the reduction diversion antireflux procedure, the quality of the corrected valve is secondary, and the main goal is to avoid the reflux of injurious components of the refluxate instead of the refluxate itself, which is almost always impossible. Late results support this hypothesis, and the authors propose this surgical procedure as an alternative treatment in patients who have complicated BE or in patients who have long-segment BE. Among patients who have gastroesophageal reflux and intestinal metaplasia of the cardia or with a noncomplicated short-segment BE, laparoscopic antireflux surgery is the authors' first choice, and only the late objective evaluation of surgical treatment demonstrates which surgical technique is the more adequate to a particular patient who has BE.

Duodenogastroesophageal reflux and methods to monitor nonacidic reflux

The role of duodenogastroesophageal reflux (DGER), once erroneously termed "bile reflux," in causing esophageal mucosal damage has been an area of interest in both animal and human studies. However, because of the lack of appropriate techniques to accurately measure DGER, extrapolation of findings from animal studies to humans has been difficult to make. The recent advent of the Bilitec system (Metronics Instruments, Minneapolis, MN), an ambulatory bilirubin monitoring device, is increasing our knowledge of the specific role of DGER in esophageal diseases. Studies suggest that DGER without acid reflux may result in symptoms, but unless acid reflux is present simultaneously, it does not cause esophagitis. Therefore, therapies should aim at reducing both DGER and acid reflux. Studies show that this may be accomplished by antireflux surgery or the use of proton pump inhibitors, which by reducing gastric volume, decrease the damaging potential of both acid and DGER.

Reflux and pH: 'alkaline' components are not neutralized by gastric pH variations

The ability of the 'alkaline' components of reflux to cause harm in vivo is still open to debate, although these components have been shown in vitro to be capable of damaging the mucosa. The precipitation of bile acids and lysolecithin that occurs at low pH values is the main reason for questioning in vivo mucosal damage. This study was undertaken to determine the composition of gastric aspirates at different original pH values and the degree of solubility of the alkaline components when pH modifications are artificially induced. The samples for chemical analysis were collected from indwelling nasogastric tubes after surgical procedures that did not involve the upper gastrointestinal tract. Bile acid and lysolecithin concentrations were assessed by means of dedicated methods. Thirty-five samples were available for bile acid evaluation and 27 for lysolecithin evaluation. Bile acid and lysolecithin assessments were repeated after pH adjustment at 2, 3.5, 5.5 and 7. For easier assessment of the results, three ranges of the original pH were selected (pH < 2, 2 < or = pH < 5, pH > or = 5). For each pH range, results were pooled together and compared with those in the other pH ranges. Bile acid concentrations were 113+/-48, 339+/-90 and 900+/-303 (mean +/- s.e.m. micromol/L), respectively, in the three groups selected on account of the different original pH values. Differences were significant (p < 0.001). Both taurine- and glycine-conjugated bile acids were represented even at pH < 2. No major differences were observed in bile acid concentration with the artificially induced pH variations. Lysolecithin concentrations were 5.99+/-3.27, 30.80+/-8.43 and 108.37+/-22.17 (mean +/- SEM microg/ml), respectively, in the three groups selected on account of the different original pH ranges. Differences were significant (p < 0.001). No significant differences in lysolecithin concentration were detected with the artificially induced pH variations. In conclusion, both bile acids and lysolecithin are naturally represented in the gastric environment even at very low pH values, although their concentrations decrease on lowering of the naturally occurring pH. Given the concentration variability of bile acids and lysolecithin, further studies are needed to assess the minimal concentration capable of mucosal damage in vivo.

Review article: the role of non-acid reflux in gastro-oesophageal reflux disease

The role of acid in the pathogenesis of gastro-oesophageal reflux disease (GERD) has been extensively studied and is well accepted. The role, if any, of non-acid reflux, in particular duodenogastro-oesophageal reflux, is much debated. The availability of new technology to detect non-acid reflux has heightened interest in this question. This article reviews the following: How do we define non-acid reflux? Does duodenogastro-oesophageal reflux (alone or in combination) cause oesophageal injury, symptoms or both? What is its role in complicated GERD? What methods are available to assess non-acid reflux? Does non-acid reflux need treatment and if so what modalities are available?

Bile reflux into the esophagus. Bilitec 2000 measurements in normal subjects and in patients after Nissen fundoplication

BACKGROUND

Bilitec 2000 is a new spectrophotometric system that can detect bilirubin within the esophagus. The aim of this study was to test this new system in vitro and in vivo with special attention to patients operated on laparoscopically for gastroesophageal reflux with Nissen fundoplication.

METHODS

In vitro studies of gallbladder bile dilution curves at different pHs were performed with a combined pH and Bilitec probe and by investigation of the drift of the Bilitec system. In vivo studies were performed in 34 normal individuals and 12 patients operated on with a laparoscopic Nissen fundoplication. Intra/intervariations were evaluated in normal individuals.

RESULTS

The Bilitec system was able to detect changes in absorbance value within the range 0.14-0.6. Absorbance values were about 30% lower in an acid environment. The percentage of the total time with bile reflux was a median (range) of 3.9 (0-49.6) in normal individuals, with an intravariation within the intervariation, and 8.7 (0-36.6) in patients after a Nissen fundoplication. These values did not differ significantly. Eighty-two per cent of the normal subjects had some degree of bile reflux, if an absorbance value > or = 0.14 was accepted as the threshold value for the presence of bile reflux.

CONCLUSIONS

Bile reflux in normal individuals is frequent and not different from that in patients after a Nissen fundoplication. Surprisingly, the latter had bile reflux but no or minimal acid reflux. Factors other than bilirubin may interfere with the measurements.

Gastro-oesophageal reflux in infancy

Gastro-oesophageal reflux (GOR) is a common phenomenon in infants, which may occur with or without accompanying symptoms. Although most infants presenting with regurgitation have a normal physical examination, it is now recognized that infants may also present with a wide variety of symptoms. Oesophagitis is associated with increased oesophageal acid exposure. The determination of cause and effect is difficult, as there are many aspects of reflux disease where cause and effect relationships are cyclic. Reflux disease is present when there is an imbalance between a number of factors that can contribute to a decrease, as well as an increase, of GOR. Oesophageal pH monitoring with a semi-disposable monocrysant antimony pH catheter with three sensors is very good at documenting oesophageal acidification and gastric buffering and, therefore, quantifies acid reflux frequency and duration. However, the interpretation of the data is complex as they are influenced by numerous factors, such as position, activity (sleep, crying), feeding (frequency and composition) or medication. The duration of buffering of gastric acidity during pH monitoring might, in the future, appear to be a relevant factor in the interpretation of oesophageal pH data.

Assessment of combined bile acid and pH profiles using an automated sampling device in gastro-oesophageal reflux disease

BACKGROUND

Bile acid reflux is an important component of duodenogastro-oesophageal reflux but there is no effective method of quantifying it. The contribution of bile acids to oesophageal pH is unknown.

METHODS

Oesophageal aspirates were collected over 15 h using a new automated suction device and pH was monitored in ten asymptomatic volunteers (group 1) and 30 patients with reflux oesophagitis (group 2, minimal mucosal injury; group 3, erosive oesophagitis; group 4, stricture or Barrett's oesophagus). Bile acid assay was performed by high-performance liquid chromatography.

RESULTS

The concentration of bile acids was significantly higher in group 3 (median (interquartile range) 124 (50-301) mumol/l) and group 4 (181 (85-591) mumol/l) compared with group 1 (0 mumol/l) and group 2 (14 (0-100) mumol/l). Patients in groups 3 and 4 also had significantly greater DeMeester acid scores. Combined bile acid and oesophageal acid reflux was observed in eight of ten patients with stricture or Barrett's oesophagus. There was no correlation between total bile acid concentration and oesophageal acid or alkaline exposure.

CONCLUSION

This study supports the theory of toxic synergism between acid and bile acids in reflux oesophagitis. Bile acids may contribute to the pathogenesis of Barrett's metaplasia.

Composition and concentration of bile acid reflux into the esophagus of patients with gastroesophageal reflux disease

BACKGROUND

Reflux of duodenal contents into the esophagus of patients with gastroesophageal reflux disease has been suggested by pH and bilirubin monitoring but is rarely directly measured. A portable device has been developed and was used to collect and quantitate material refluxed into the esophagus under ambulatory conditions during a prolonged time period. The objective of this study was to use this device to quantitate the composition and concentration of bile acids refluxed into the esophagus of patients with gastroesophageal reflux disease.

METHODS

Esophageal aspiration was performed on 43 normal subjects and 37 patients with reflux disease during a 17-hour period. Aspiration was performed through a modified 16F Salem sump tube, positioned 5 cm above the lower esophageal sphincter and connected to a portable, battery powered pump that aspirated continuously at 100 mm Hg pressure. Validation studies showed that minimal amounts of saliva and swallowed liquids were aspirated and that gastric pressure was not altered. Postprandial, upright, and supine collections were performed. Total bile acids were assayed by a standard enzymatic assay; specific conjugated bile acids were analyzed by high-performance liquid chromatography.

RESULTS

There was no difference in the total aspiration volume between normal volunteers and patients with gastroesophageal reflux disease, although patients tended to have a higher volume in the supine and postprandial periods. Bile acids could be detected in 58% of normal subjects and 86% of patients (p < 0.003). The mean concentration of bile salt exposure (micromole per liter) was higher in patients during the postprandial and supine periods. The mean bile acid reflux rate (micromole per hour) during all three aspiration periods was significantly higher in patients. On a molar basis the composition of the bile acids was 60% glycocholic acid, 16% glycodeoxycholic acid, and 15% glycochenodeoxycholic acid. Taurocholic, taurodeoxycholic, taurochenodeoxycholic, and glycolithocholic acid constituted the remaining 10%.

CONCLUSIONS

Patients with reflux disease have an increased concentration of bile acids in their esophageal aspirates. Most of the exposure occurs during the postprandial and supine periods. A variety of bile acids were detected, most of which were in their glycine conjugated form.

Bile reflux in columnar-lined esophagus

Barrett's esophagus represents a metaplastic process in which the normal squamous epithelium of the lower esophagus is replaced by metaplastic columnar epithelium. Although the role of acid and pepsin in the development of Barrett's esophagus is well accepted, the importance of duodenogastroesophageal reflux in this disorder is not clear.

A new physiologic approach for the surgical treatment of patients with Barrett's esophagus: technical considerations and results in 65 patients

OBJECTIVE

To determine the results of a new surgical procedure for patients with Barrett's esophagus.

SUMMARY BACKGROUND DATA

In addition to pathologic acid reflux into the esophagus in patients with severe gastroesophageal reflux and Barrett's esophagus, increased duodenoesophegeal reflux has been implicated. The purpose of this study was to establish the effect of a new bile diversion procedure in these patients.

METHODS

Sixty-five patients with Barrett's esophagus were included in this study. A complete clinical, radiologic, endoscopic, and bioptic evaluation was performed before and after surgery. Besides esophageal manometry, 24-hour pH studies and a Bilitec test were performed. After surgery, gastric emptying of solids, gastric acid secretion, and serum gastrin were determined. All patients underwent highly selective vagotomy, antireflux procedure (posterior gastropexy with cardial calibration or fundoplication), and duodenal switch procedure, with a Roux-en-Y anastomosis 60 cm in length.

RESULTS

No deaths occurred. Morbidity occurred in 14% of the patients. A significant improvement in symptoms, endoscopic findings, and radiologic evaluation was achieved. Lower esophageal sphincter pressure increased significantly (p < 0.0001), as did abdominal length and total length of the sphincter (p < 0.0001). The presence of an incompetent sphincter decreased from 87.3% to 20.9% (p < 0.0001). Three of seven patients with dysplasia showed disappearance of this dysplasia. Serum gastrin and gastric emptying of solids after surgery remained normal. Basal and peak acid output values were low. Twenty-four hour pH studies showed a mean value of 24.8% before surgery, which decreased to 4.8% after surgery (p < 0.0001). The determination of the percentage time with bilirubin in the esophagus was 23% before surgery; this decreased to 0.7% after surgery (p < 0.0001). Late results showed Visick I and II gradation in 90% of the patients and grade III and IV in 10% of the patients.

CONCLUSIONS

This physiologic approach to the surgical treatment of patients with Barrett's esophagus produces a permanent decrease of acid secretion (and avoids anastomotic ulcer), decreases significantly acid reflux into the esophagus, and abolishes duodenoesophageal reflux permanently. Significant clinical improvement occurs, and dysplastic changes at Barrett's epithelium disappear in almost 50% of the patients.

Bile in the oesophagus: clinical relevance and ambulatory detection

BACKGROUND

Experimental work in animals has implicated a role for bile in the pathogenesis of several oesophageal mucosal diseases such as oesophagitis, Barrett's oesophagus and oesophageal adenocarcinoma. Recent descriptions of a high incidence of intestinal metaplasia at the gastro-oesophageal junction in patients without a classical 3-cm Barrett's columnar-lined segment, combined with a rising incidence in oesophageal and cardia adenocarcinoma, have stimulated interest in the causes of these conditions.

METHODS AND RESULTS

Animal studies concerned with defining the role of the various gastroduodenal reflux constituents in oesophageal mucosal injury are summarized and evidence for bile in the pathogenesis of Barrett's oesophagus and oesophageal adenocarcinoma is reviewed. The results of various techniques for clinical measurement of oesophageal bile reflux, such as aspiration, scintigraphy and pH monitoring, are evaluated and the significance of recent studies employing ambulatory fibreoptic bilirubin monitoring is discussed.

CONCLUSION

There seems little doubt that bile plays a significant role in oesophageal mucosal disease, in synergy with other constituents of reflux. Although ambulatory bilirubin monitoring is new, some intriguing findings have been reported and it is hoped that this technique will continue to shed light on the role of bile in the oesophagus.

Placebo-controlled trial of cisapride in postgastrectomy patients with duodenogastroesophageal reflux

Medical treatment of duodenogastroesophageal reflux in postgastrectomy patients has been disappointing. Using ambulatory esophageal bilirubin monitoring, we evaluated the efficacy of cisapride in this disorder. Ten chronically symptomatic partial gastrectomy patients (5 Billroth I, 5 Billroth II; 8 men; average age 57) with duodenogastroesophageal reflux were randomized to four weeks of either placebo or cisapride (20 mg four times a day) in a double-blind crossover study. Significantly improved patients continued to take cisapride for an additional four months. Duodenogastroesophageal reflux was assessed at baseline and after four weeks on each therapy. Daily diary recorded symptoms and mean monthly scores were determined. Global symptom improvements were assessed at the end of each treatment period. Compared to placebo, cisapride significantly (P < 0.05) decreased duodenogastroesophageal reflux. Overall symptom improvements were assessed at the end of each treatment period. Compared to placebo, cisapride significantly (P < 0.05) decreased duodenogastroesophageal reflux. Overall symptoms improved in 70% of patients on cisapride compared to 10% on placebo (P < 0.01). Mean monthly scores significantly (P < 0.05) improved for abdominal pain, regurgitation, and belching. These symptoms remained improved after four months of chronic therapy. We conclude that cisapride significantly reduces duodenogastroesophageal reflux and results in short- and long-term symptom improvements in postgastrectomy patients and that cisapride offers the first successful medical therapy for duodenogastroesophageal reflux in postgastrectomy patients.

The pathophysiology of gastro-oesophageal reflux disease: an overview

Gastro-oesophageal reflux disease (GORD) is a multifactorial disease. Although it is primarily a motility disorder, several other disturbances can interfere and contribute to determine the severity of symptoms and the degree of lesions. In normal subjects, as in patients with pathological reflux, nearly all the episodes of reflux obey one of the following three mechanisms: (a) a transient complete relaxation of the lower oesophageal sphincter (TLOSR), (b) a transient increase in intra-abdominal pressure which overcomes the resistance of the antireflux barrier ('stress reflux') and, (c) a spontaneous reflux through a permanently hypotonic sphincter. Gastric distension is the major factor that can induce TLOSRs. Whereas, at rest, the diaphragm probably plays little role in cardial competence, diaphragmatic contraction may help prevent reflux in conditions resulting in increased abdominal pressure such as during physical activity and abdominal staining. The presence of a hiatal hernia increases susceptibility to reflux. A delayed gastric emptying may also facilitate reflux and represents a factor of resistance to antireflux therapy. Most studies in humans have shown that motor abnormalities remain unchanged after healing of oesophagitis. Acid and pepsin are the most noxious agents of the upper gastrointestinal secretions that can participate in the pathogenesis of oesophagitis. However, there is no evidence that patients with reflux have greater acid secretion than subjects without reflux. The clearance function is a two-stage phenomenon requiring first a reduction in volume by peristalsis and then chemical neutralization by saliva. Primary peristalsis is mainly responsible for the clearance of acid in both the upright and the supine positions. It takes longer to clear acid in patients with non-reducing hiatal hernia. The layer of mucus which carpets the mucosa comes from the saliva and also from the submucosal glands of the oesophagus. The paracellular pathway is the major route by which mucosal HCl enters and then damages the oesophageal epithelium. Only a minority of acid reflux episodes are accompanied by symptoms. The acid exposure during the time period that precedes a reflux episode (i.e. the acid burden) is a key factor determining whether that reflux episode will be symptomatic or asymptomatic.

Duodenogastroesophageal reflux: relationship to pH and importance in Barrett's esophagus

BACKGROUND/AIMS

Several reports suggest that duodenogastroesophageal reflux may produce esophagitis, Barrett's esophagus, and esophageal adenocarcinoma. The purpose of this study was to understand better the relationship of pH (< 4 and > 7), duodenogastroesophageal reflux, and fasting bile acid concentrations in producing esophageal damage.

METHODS

Using a spectrophotometric technique to measure bile reflux, four groups were studied: healthy subjects, reflux patients, patients with Barrett's esophagus, and patients with esophageal symptoms after partial gastrectomy.

RESULTS

Simultaneous 24-hour pH and bile monitoring of distal esophagus found close association between total percent of time pH < 4 and duodenogastroesophageal reflux (r = 0.78; P < 0.001) but a poor relationship (r = -0.06) with total percent of time pH > 7, suggesting that the term alkaline reflux is a misnomer. Duodenogastroesophageal reflux increased significantly with the severity of reflux disease, being greatest in patients with Barrett's esophagus and comparable with that in patients with partial gastrectomy. Fasting bile acid concentrations did not distinguish patients with Barrett's esophagus from those with reflux. Rather, increased quantity of acid reflux was the single factor most characterizing patients with Barrett's esophagus. Omeprazole (20 mg twice daily) normalized acid reflux parameters (13.8% +/- 1.6% to 0.8% +/- 0.6%) and significantly (P < 0.001) decreased duodenogastroesophageal reflux (32.8% +/- 6.9% to 4.7% +/- 1.7%).

CONCLUSIONS

Acid reflux is the primary factor in the development of Barrett's esophagus. Bile reflux parallels acid reflux and, at best, may have a synergistic role. Aggressive acid suppression with omeprazole markedly decreases both.

Alkaline gastroesophageal reflux: assessment by ambulatory esophageal aspiration and pH monitoring

The pathophysiologic effect of duodenal contents in the refluxed gastric juice of patients with gastroesophageal reflux disease (GERD) is controversial. We evaluated the composition of the refluxed gastric juice in 43 normal volunteers and 52 patients with GERD using a newly developed device that allows ambulatory esophageal aspiration. The findings were correlated with the results of 24-hour esophageal pH monitoring and the presence of complications of GERD. Compared with bile concentrations in normal volunteers, the total bile acid concentration in the reflux aspirates was higher in patients with GERD (p < 0.01). There was a significant correlation between the bile acid concentration in the aspirates and the percentage of time the pH was above 7 on ambulatory 24-hour esophageal pH monitoring (r = 0.59, p = 0.006), and both were highest during the night (p < 0.01). The bile acid concentration and the percentage of time pH was greater than 7 were particularly increased in patients with strictures or Barrett's esophagus (p < 0.01). Both an increased bile acid concentration in aspirates and the percentage of time with pH greater than 7 on pH monitoring were observed primarily in patients with a destroyed gastroduodenal barrier [status post Billroth II resection (BII), Billroth I resection (BI), or pyloroplasty] or after cholecystectomy. An increased bile acid concentration also occurred in a substantial number of patients without previous foregut surgery, although this did not usually result in an increase in the time that pH was above 7. These data suggest that contamination of the refluxed gastric juice with bile acids predisposes the patient to the development of strictures and Barrett's esophagus. An increased time that pH is greater than 7 on esophageal pH monitoring indicates biliary reflux and occurs primarily after previous foregut surgery. A normal-time pH above 7 does, however, not exclude contamination of the refluxed gastric juice with duodenal contents.

'Bile' in the oesophagus

Acid gastro-oesophageal reflux occurs when the lower oesophageal sphincter is incompetent, but oesophagitis caused by reflux of duodenal content implies incompetence of both the pyloric and gastro-oesophageal sphincters. The term 'alkaline' reflux oesophagitis was coined long before objective analysis was made of bile in the stomach and oesophagus, and well before pH monitoring was introduced. Surgical procedures to divert bile from the stomach and oesophagus were developed on a clinical basis and gave encouraging results in the management of peptic oesophageal stricture. Alkaline oesophagitis is well recognized after gastric surgery and the entity 'primary pathological duodenogastric reflux', although contested by some, attracts growing support. Recent evidence suggests that the complications of Barrett's oesophagus may be related to duodenogastro-oesophageal reflux. Probes designed to measure gastric and oesophageal bile salts have recently been developed and may give more information in the future.

Determinants of oesophageal 'alkaline' pH environment in controls and patients with gastro-oesophageal reflux disease

The determinants of the oesophageal alkaline pH environment are poorly understood. Saliva (pH 6.4-7.8) may be a major contributor, although some argue the importance of refluxed alkaline duodenal contents. Acid and alkaline reflux parameters were studied over 2 days in 30 subjects (control, oesophagitis and Barrett's patients; 10 each) using glass pH electrodes. In phase 1, one pH electrode was placed 1 cm below the upper oesophageal sphincter to assess the influence of saliva and the other 5 cm above the lower oesophageal sphincter. Phase 2 was identical except that one pH probe was 5 cm below the lower oesophageal sphincter to record duodenogastric reflux. Patient groups spent, on average, 50 fold more time during the upright and supine periods at acidic pH than controls. Saliva was responsible for the percentage of time the pH > 7 and contributed significantly to the percentage of time the pH > 6 in both the proximal and distal oesophagus of control subjects, as shown by an absence of pH > 7 and a significant (p < 0.001) fourfold decrease in pH > 6 during sleep. A similar pattern was seen in the proximal oesophagus of both reflux groups. The reflux and Barrett's patients, however did not show a significant decrease in the percentage of time the pH > 6 at night in the distal oesophagus suggesting a relative increase in 'alkaline' exposure from another source. This was not because of duodenogastric reflux as the corresponding pH rises in the fundus of the stomach were non-existent. Although this was not studied specifically, it is believed to be a protective meachanism, the result of alkaline secretion produced by submucosal oesophageal glands.

Gastric acidity and gastroesophageal reflux patterns in patients with esophagitis

Esophageal pH-metry is the test of choice for diagnosing gastroesophageal reflux. However, although it allows acid refluxes to be distinguished, it is of limited value for identifying alkaline or mixed (acid mixed with alkaline material) refluxes. To evaluate the ability of dual pH-metry to identify alkaline or mixed refluxes, the gastric acidity and gastroesophageal reflux pattern were evaluated simultaneously in 64 patients with mild-moderate esophagitis, in 28 patients with severe or complicated esophagitis, and in 20 healthy subjects. A dual esophageal gastric pH-probe allowed three different types of esophageal reflux to be distinguished: (a) acid refluxes, defined as a drop in esophageal pH to values less than 4 together with a gastric pH less than 4; (b) mixed refluxes, defined as a drop in esophageal pH from baseline to values greater than 4 associated with rises in gastric pH to greater than 4 values; (c) alkaline refluxes, defined as a rise in esophageal pH to greater than 7 associated with a simultaneous increase in gastric pH to greater than 4. Gastric acidity was more significantly reduced in patients with severe or complicated esophagitis than it was in healthy subjects (P less than 0.01). The reflux pattern in both mild-moderate and severe esophagitis was characterized by mainly acid refluxes and a marked increase in the time the esophagus mucosa was exposed to acid (P less than 0.001). Pure alkaline refluxes were rare (less than 1%) in both healthy subjects and esophagitis patients. The number of mixed refluxes was considerably higher in severe esophagitis patients than it was in either mild-moderate esophagitis patients or controls (P less than 0.05). The finding of mixed refluxes in severe or complicated esophagitis suggests that biliary acids and/or pancreatic enzymes are involved in the pathogenesis of severe forms of esophagitis.

Complications of gastroesophageal reflux disease. Role of the lower esophageal sphincter, esophageal acid and acid/alkaline exposure, and duodenogastric reflux

The factors contributing to the development of esophageal mucosal injury in gastroesophageal reflux disease (GERD) are unclear. The lower esophageal sphincter, esophageal acid and acid/alkaline exposure, and the presence of excessive duodenogastric reflux (DGR) was evaluated in 205 consecutive patients with GERD and various degrees of mucosal injury (no mucosal injury, n = 92; esophagitis, n = 66; stricture, n = 19; Barrett's esophagus, n = 28). Manometry and 24-hour esophageal pH monitoring showed that the prevalence and severity of esophageal mucosal injury was higher in patients with a mechanically defective lower esophageal sphincter (p less than 0.01) or increased esophageal acid/alkaline exposure (p less than 0.01) as compared with those with a normal sphincter or only increased esophageal acid exposure. Complications of GERD were particularly frequent and severe in patients who had a combination of a defective sphincter and increased esophageal acid/alkaline exposure (p less than 0.01). Combined esophageal and gastric pH monitoring showed that esophageal alkaline exposure was increased only in GERD patients with DGR (p less than 0.05) and that DGR was more frequent in GERD patients with a stricture or Barrett's esophagus. A mechanically defective lower esophageal sphincter and reflux of acid gastric juice contaminated with duodenal contents therefore appear to be the most important determinants for the development of mucosal injury in GERD. This explains why some patients fail medical therapy and supports the surgical reconstruction of the defective sphincter as the most effective therapy.

What has the surgeon to know about pathophysiology of reflux disease?

Much has been learned about the pathophysiology of gastro-esophageal reflux (GER) since it was initially described by Asher Winkelstein in 1935. With the development and refinement of esophageal function tests in the past decades, the diagnostic modalities have become available for a deliberate and systematic evaluation of antireflux mechanisms. Some of the newer concepts of the pathogenesis of reflux esophagitis are reviewed in this article.

Duodenogastric reflux in patients with Barrett's esophagus

The role of duodenogastric reflux in the pathogenesis of gastroesophageal reflux disease is not clear. Using hepatobiliary scanning techniques, we found evidence of duodenogastric reflux in six of 13 patients with Barrett's esophagus. This compares with only two positive studies in 19 control subjects. This difference is statistically significant (P = 0.038, two-tailed Fisher's exact test). Three of nine patients who had gastroesophageal reflux without Barrett's esophagus had evidence of duodenogastric reflux, a frequency not significantly different from either of the other groups. Gastroesophageal reflux of bile and pancreatic enzymes, in addition to gastric acid may contribute to the greater esophageal damage often seen in Barrett's esophagus. The presence of duodenogastric reflux in these patients may have important pathophysiologic and therapeutic implications.

Is there an abnormal fasting duodenogastric reflux in nonulcer dyspepsia?

A quantitatively and/or qualitatively abnormal duodenogastric reflux (DGR) could be involved in the pathogenesis of nonulcer dyspepsia (NUD). The aims of this prospective study were to look for (1) a pathological DGR profile during fasting and (2) an eventual correlation between DGR profile and clinical symptoms. Twenty-six NUD patients were investigated. Seven other operated patients with a surgical procedure facilitating DGR episodes and 27 healthy volunteers served as control groups. A clinical score was determined for each patient from a standardized questionnaire. Gastric aspiration was performed for 6 hr in fasting subjects. The aspirates were pooled into 17 samples. In each sample the concentration and the output of total bile acids was determined. If the concentration was larger than 30 mumol/liter in pooled samples, the concentrations of free bile acids and the distribution of the conjugated bile acids was determined. The percentage of aliquots with a total bile acid concentration larger than 50 mumol/liter (without upper limit), and the percentage with a concentration larger than 2500 mumol/liter was also obtained. No significant difference was demonstrated between the healthy volunteers and NUD patients, whatever the parameter considered. However, there was a significant increase in each of the quantitative parameters for the group of operated patients in comparison with the NUD patient group. No significant correlation was found between the clinical score and the DGR profile in NUD patients. Apparently, DGR episodes do not play a primary role in the pathogenesis of NUD.

Changes in intragastric bile acid composition in patients receiving cimetidine postoperatively

Enterogastric reflux has been implicated as a possible etiologic mechanism in gastritis both after partial gastrectomy and in those with an intact pylorus. We studied the effects of cimetidine on bile acid concentration and composition by high-performance liquid chromatography. The gastric aspirates collected for this study came from 27 prospectively randomized patients receiving intravenous cimetidine (200 mg every 6 hours) and 25 patients given a placebo. Total bile acid concentration of aspirates was determined spectrophotometrically. Marked differences were noted in conjugated bile acids. Glycochenodeoxycholic acid, a toxic dihydroxy bile acid, was decreased after cimetidine compared with results from the placebo. The ratio of less toxic trihydroxylated to more toxic dihydroxylated bile acids was significantly increased. Enterogastric reflux itself seemed unaltered by cimetidine; likewise, the concentration of total bile acids in the cimetidine group was similar to that among patients receiving placebo. These changes in bile salt composition with cimetidine may help explain its salutary effects in gastritis, over and above its ability to reduce gastric hydrogen ion secretion.

Review article: a role for gastrointestinal prokinetic agents in the treatment of reflux oesophagitis?

Gastro-oesophageal reflux disease may result from a host of factors. Medical therapy has largely been aimed at neutralizing acid or decreasing acid production but improvement of upper-gastrointestinal motility may prove to be a valuable treatment modality as well. This paper reviews the current state of knowledge of the pathogenesis of reflux disease and concentrates upon promotility treatment with domperidone, metoclopramide and cisapride.

Evaluation of omeprazole in reflux oesophagitis

In patients with reflux disease, pH monitoring has shown that omeprazole virtually eliminates oesophageal exposure to a pH of less than 4. Motility studies concurrent with pH monitoring have indicated that reflux continues on omeprazole, its effect on acid exposure being entirely dependent on elevation of gastric pH. Omeprazole and placebo have been compared in 64 patients with erosive or ulcerative oesophagitis; the 4-week healing rates were 81% with omeprazole, 20 mg or 40 mg daily, and 6% with placebo. The efficacies of omeprazole at doses of 20 mg and 40 mg daily, were then compared in 164 patients. At 4 weeks, oesophagitis was healed in 70% and 82% of patients for the 20 mg and 40 mg doses respectively (p = 0.05). Eight-week healing rates (79% for 20 mg and 85% for 40 mg) did not differ significantly. Symptom response was excellent for both doses. Relapse of oesophagitis was determined over 6 months for patients healed with omeprazole. Relapse was shown to occur in 88 of 107 patients by 6 months. Omeprazole is a highly effective treatment for erosive/ulcerative peptic oesophagitis, 40 mg daily being marginally superior to 20 mg. Relapse is almost inevitable within 6 months of cessation of therapy.

Alkaline intra-oesophageal pH and gastro-oesophageal reflux in patients with peptic oesophagitis

Simultaneous 22-h measurements of intra-oesophageal and intragastric pH were made in 22 patients with symptoms of gastro-oesophageal reflux (7 with peptic oesophagitis, 8 with peptic oesophageal stricture, and 7 with peptic oesophagitis and previous partial gastrectomy) to determine whether alkaline intra-oesophageal pH is a consequence of alkaline gastro-oesophageal reflux. In the three groups of patients intra-oesophageal pH was greater than 7 for 16.9 +/- 4.8%, 27.5 +/- 7.6%, and 21.0 +/- 7.7%, respectively, of total recording time (p = NS). Intragastric pH greater than 7 was recorded only in the patients with partial gastrectomy (10.3 +/- 5.3% of recording time; p less than 0.01 in comparison with the other groups). Elevations of intra-oesophageal pH to greater than 7 never occurred during episodes of alkalinization of intragastric pH. These results suggest that refluxed fluids are unlikely to be the cause of alkaline intra-oesophageal pH in patients with peptic oesophagitis.

Bile salts in the esophagus of patients with esophagitis

It is controversial whether bile salts are important in the pathogenesis of esophagitis. By sampling esophageal contents during ambulatory 24-h pH-monitoring we found that in a group of 18 patients with esophagitis all but 1 had detectable concentrations of bile salts in their esophagus. The concentrations of bile salts were low, however, and similar to those found in the gastric juice of 10 normal controls. It is concluded that bile salts are present in the esophagus of patients with esophagitis and that their presence results from duodenogastric reflux. The role of these refluxed bile salts in the pathogenesis of esophagitis is, however, unclear.

Bile acid concentrations in the refluxate of patients with reflux oesophagitis

Although reflux of bile acids has been implicated in the pathogenesis of reflux oesophagitis, attempts to document this in vivo have failed to detect more than trace amounts of bile acid in the oesophagus. To determine the bile acid composition of oesophageal refluxate, 45 patients with abnormal acid gastro-oesophageal reflux with oesophagitis and 10 controls had a size 14 Fr Salem sump tube positioned 5 cm above the lower oesophageal sphincter. Oesophageal contents were continuously aspirated and collected in aliquots every 2 h over 16 h. Fasting, postprandial, upright and supine (nocturnal) periods were assessed and total conjugated bile acids were measured by high pressure liquid chromatography with a sensitivity of 8 mumol/l. Conjugated bile acids were detected in 2 of 10 controls (maximum 40 mumol/l) and in 39 of 45 patients (87 per cent). Eleven patients had peak conjugated bile acid levels greater than 200 mumol/l, and these levels occurred exclusively during the supine (nocturnal) period. Median conjugated bile acid levels during daytime reflux were less than 20 mumol/l which was significantly lower than during nocturnal reflux (median 51 mumol/l, P less than 0.001). Conjugated bile acids are detected in the oesophagus of most patients with oesophagitis and may play a role in the pathogenesis of oesophagitis in some patients with nocturnal gastro-oesophageal reflux.

Aetiology, pathogenesis, and clinical manifestations of gastro-oesophageal reflux disease

The aetiologic factors in gastro-oesophageal reflux disease include the free reflux of gastric juice, the composition of refluxed juice, the defensive mechanisms of the oesophagus, which are both mechanical and mucosal, and, sometimes, gastric abnormalities. Symptoms include heartburn, odynophagia, chest pain, dysphagia, regurgitation, and, occasionally, haemorrhage. Respiratory symptoms may occur. Diagnosis is based on determining the pressure and frequency of reflux (for which pH monitoring is preferred), testing for symptoms that may be caused by reflux, and assessing the degree of oesophagitis, for which endoscopy and histology are the only known techniques.

Recent views on the pathogenesis of gastro-oesophageal reflux disease

The pathogenesis of GORD depends on a mix of factors which vary amongst individual patients. The central issue in the pathogenesis of gastro-oesophageal reflux is understanding of the mechanisms that lead to reflux, since the effects of all other factors depend on this event. Consequently, new information and views about the mechanisms of gastro-oesophageal reflux have been presented in detail. This information suggests that defective lower oesophageal sphincter motility is the most important abnormality that underlies pathological gastro-oesophageal reflux. Two major forms of LOS dysfunction have been identified as responsible for pathological gastro-oesophageal reflux in the horizontal position: (1) an excessively frequent rate of occurrence of transient LOS relaxations; and (2) defective basal LOS tone. Both of these dysfunctions appear to arise from abnormal neural control of the LOS, probably by the central nervous system. The effect of these LOS dysfunctions on gastro-oesophageal competence is probably significantly influenced by non-sphincteric factors, the most important of these apparently being hiatus hernia. Though there is currently poor understanding about the ways in which hiatus hernia impairs gastro-oesophageal competence, measurement techniques have now advanced sufficiently to allow significant accrual of knowledge in this field. Once reflux has occurred, the efficiency of oesophageal acid clearance plays a major role in determining the impact of reflux on the oesophageal mucosa. Recent studies have shown that oesophageal acid clearance depends on both effective volume clearance and neutralization by saliva of residual acid in the oesophageal lumen. The efficiency of oesophageal volume clearance of both stimulated and real reflux has not been studied formally in GORD patients, but the high incidence of peristaltic dysfunction in reflux disease suggests that volume clearance will be defective in some patients. The limited information available about salivation in GORD patients suggests that salivary secretion is no different from that of age-matched controls, but that there is an age-dependent loss of the salivary response to oesophageal acidification. This impairment of salivary response may produce an age-dependent decline of the efficiency of oesophageal acid clearance. Unusually aggressive refluxate and impaired mucosal resistance to injury have been proposed as significant variables which contribute to pathogenesis of reflux disease. The evidence for these factors is circumstantial and scanty. Their importance has probably been overestimated.(ABSTRACT TRUNCATED AT 400 WORDS)