[Pathogenesis of gastro-esophageal reflux disease]

Gastro-esophageal reflux disease (GERD) refers a condition that develops when the reflux of stomach contents causes troublesome symptoms and/or complications. The disease was subclassified into esophageal and extraesophageal syndromes in the new Montreal Definition. Hiatal hernia, decreased lower esophageal sphincter, transient lower esophageal sphincter relaxation, esophageal acid clearance, and delayed gastric emptying might be implicated as the pathogenesis of esophageal syndrome. Although non-erosive reflux disease (NERD) is included in the esophageal syndrome, it might be different from reflux esophagitis because of the lower response rates to acid suppression with proton pump inhibitors. Esophageal visceral hypersensitivity, sustained esophageal contractions, and abnormal tissue resistance are thought to be the mechanisms of NERD. Further investigations for the pathogenesis of each classification are expected.

[Helicobacter pylori infection and GERD]

Helicobacter pylori (H. pylori) is an important pathogen that is known to be associated with gastritis, peptic ulcer diseases, and gastric cancer. The association between H. pylori infection and gastro-esophageal reflux disease (GERD) is, however, uncertain. Recent studies indicate that the prevalence of H. pylori is significantly lower in patient with GERD from East Asia than in patients from Western Europe and North America, and that H. pylori might protect against GERD. The frequency of hypochlorhydria might due to atrophic gastritis induced by H. pylori infection is associated with the low prevalence of GERD in Japan.

[Pathogenesis of GERD--peculiarity of NERD]

Gastroesophageal reflux disease can be divided into two groups, reflux esophagitis and non-erosive reflux disease, according to the presence of esophageal mucosal breaks. Almost all the reflux esophagitis with mucosal breaks are caused by the pathological reflux of acidic gastric contents to esophagus. Therefore, drugs that suppress gastric acid secretion effectively control reflux symptoms. On the other hand, almost 40% of nonerosive reflux disease are not caused by the reflux of gastric acid but by acid-unrelated mechanisms. Therefore, administration of proton pump inhibitors cures reflux symptom of only 50% of cases with non-erosive reflux diseases. The multi-pathogenesis of nonerosive reflux disease should be considered for the treatment of patients with reflux symptoms.

[Pathophysiology of gastroesophageal reflux disease: motility factors]

Reflux esophagitis (RE) is characterized by excessive esophageal acid exposure. The number of acid reflux episodes, the way acid comes up after reflux and the delay of acid bolus clearance cause excessive esophageal acid exposure. Transient lower esophageal sphincter relaxation(TLESR) is the major mechanism of acid reflux in both healthy subjects (HS) and in patients with acid reflux disease, but there is no difference in the rate of TLESRs or in the rate of acid reflux during TLESRs above the LES between HS and patients with severe RE. In patients with severe RE, refluxed acid above the LES rises more easily to the proximal esophagus but it does not clear easily from the esophagus when compared with HS. The pathophysiology of non-erosive reflux disease (NERD) is poorly understood, however with regard to esophageal motility in patients with NERD, the LES pressure, the pressure wave amplitude and the rates of successful primary peristalsis were similar to that of HS but the triggering of secondary peristalsis was defective. This may lead to prolonged contact time between refluxed gastric acid and esophageal mucosa thereby leading to symptoms.

[Lifestyle modification as a medical treatment for GERD]

Lifestyles such as obesity, smoking, alcohol or fatty meal are long-time considered to related with the deterioration of GERD. Basic studies indicate that smoking and alcohol decrease LES pressure. However, the clinical studies of the relationship between lifestyle and GERD sometimes show coflicting results. Lifestyle modification as a medical treatment of GERD were reviewed.

[Management of gastroesophageal reflux disease (GERD) with refractory to standard dose of proton pump inhibitor]

Approximately 10% of Japanese patients with reflux esophagitis (RE) are refractory to a standard dose of proton pump inhibitor(PPI) and most refractory patients have severe RE. Lack of response may be due to inadequate gastric acid suppression in conjunction with CYP2C19 genotype status and nocturnal acid reflux. Twice-daily dosing of PPI for inadequate gastric acid suppression and the administration of H2-receptor antagonist before bedtime for nocturnal acid reflux, is effective in most cases. The response to a standard dose of PPI in patients with non-erosive reflux disease (NERD) is approximately 50%. The reasons for a lower response rate, compared with RE patients, are not clear but may relate to an acid-hypersensitive esophagus, inadequate gastric acid suppression, non -acid reflux and emotional or psychological abnormality. High dose PPI therapy, endoscopic or surgical anti-reflux therapy, or/and pain modulators may be effective in some patients.

Prolonged esophagitis after primary dysfunction of the pyloric sphincter in the rat and therapeutic potential of the gastric pentadecapeptide BPC 157

Seven or fourteen days or twelve months after suturing one tube into the pyloric sphincter (removed by peristalsis by the seventh day), rats exhibit prolonged esophagitis with a constantly lowered pressure not only in the pyloric, but also in the lower esophageal sphincter and a failure of both sphincters. Throughout the esophagitis experiment, gastric pentadecapeptide BPC 157 (PL 14736) is given intraperitoneally once a day (10 microg/kg, 10 ng/kg, last application 24 h before assessment), or continuously in drinking water at 0.16 microg/ml, 0.16 ng/ml (12 ml/rat per day), or directly into the stomach 5 min before pressure assessment (a water manometer connected to the drainage port of a Foley catheter implanted into the stomach either through an esophageal or duodenal incision). This treatment alleviates i) the esophagitis (macroscopically and microscopically, at either region or interval), ii) the pressure in the pyloric sphincter, and iii) the pressure in the lower esophageal sphincter (cmH2O). In the normal rats it increases lower esophageal sphincter pressure, but decreases the pyloric sphincter pressure. Ranitidine, given using the same protocol (50 mg/kg, intraperitoneally, once daily; 0.83 mg/ml in drinking water; 50 mg/kg directly into the stomach) does not have an effect in either rats with esophagitis or in normal rats.

Effect of chronic renal failure on foregut smooth muscle reactivity: an experimental study

PURPOSE

An association between chronic renal failure (CRF) and gastroesophageal reflux (GER) is well known. The aim of this study was to pharmacologically characterize and investigate the possible contribution of smooth muscle reactivity pathways involving GER on the CRF rat model.

MATERIAL AND METHODS

Chronic renal failure was created in Sprague-Dawley rats by 5 of 6 nephrectomy. The rats were divided into 2 groups: the CRF-induced group (CRF group) and the sham-operated group (control group). Esophageal smooth muscle strips were studied in vitro for their contractile (KCl, carbachol) and relaxant (isoproterenol, serotonin, and papaverine) response to receptor activation in the organ chambers set up. Subsequently, the in vitro lower esophageal sphincter (LES) smooth muscle study was generated by KCl, carbachol, isoproterenol, nicotine, sodium nitroprusside (SNP), and papaverine.

RESULTS

Compared with controls, esophageal strips taken from CRF-induced rats associated with decreased smooth muscle responses to carbachol, serotonin, and increased response to KCl. Isoproterenol- and papaverine-induced relaxant responses were not affected. Contractility of the isolated LES strips were significantly increased to KCl and carbachol in the CRF group compared with the control group. Similar relaxant responses were obtained in LES strips stimulated by isoproterenol, SNP, and papaverine in the CRF and control group. Nicotine-induced relaxant responses were decreased in the CRF group compared with the control group.

CONCLUSIONS

Our study revealed alterations of receptor-dependent esophageal and LES smooth muscle reactivity in the CRF-induced rats. Impaired foregut smooth muscle reactivity may contribute to the development of GER-related functional abnormalities in patients with CRF.

Is aperistalsis with complete lower esophageal sphincter relaxation an early stage of classic achalasia?

BACKGROUND

Aperistalsis with complete lower esophageal sphincter (LES) relaxation, characterized by the complete relaxation of the LES and aperistalsis of the esophageal body on manometry, has been considered by some authors to be an early manifestation of classic achalasia, which is defined as incomplete relaxation of the LES and aperistalsis of the esophageal body. The aim of the present study was to compare the clinical features of patients with aperistalsis with complete LES relaxation, with those of patients with classic achalasia.

METHODS

Eighteen patients with aperistalsis with complete LES relaxation and 53 patients with classic achalasia were analyzed with regard to clinical history, the maximal diameter of the esophageal body on barium esophagogram, LES resting pressure and the duration of LES relaxation on manometric recordings, and the selected treatment and its efficacy.

RESULTS

The aperistalsis with complete LES relaxation group had distinctly different features compared to those of the classic achalasia group including older age, more frequent association with non-cardiac chest pain, less frequent association with dysphagia and weight loss, lower LES resting pressures, and longer duration of LES relaxation. However, the two groups were similar in terms of maximal diameter of the esophageal body, and efficacy associated with pneumatic dilation.

CONCLUSIONS

Aperistalsis with complete LES relaxation on manometry is not necessarily an early manifestation of classic achalasia. However, this condition does not preclude a diagnosis of achalasia or a good response to achalasia therapy.

Reflux Laryngitis: A Feasible Indication for Laparoscopic Antireflux Surgery?

Laparoscopic fundoplication is a routine surgical approach in the treatment of moderate or severe gastro-esophageal reflux disease. However, there are still contradictions regarding supraesophageal symptoms as an indication for surgery. The aim of this study was to determine the subjective symptomatic outcome and objective laryngeal findings after antireflux surgery in patients with pH monitoring proven reflux laryngitis. Between 1998 and 2002, 40 patients with reflux laryngitis underwent laparoscopic Nissen fundoplication. Patients were referred to surgery and followed-up by a specialist in otorhinolaryngology. Subjective symptoms were collected by a structured questionnaire at a median follow-up of 42 months. The objective laryngeal findings improved from the preoperative situation; at 12 months after surgery, the otorhinolaryngeal status was improved in 92.3% (n=24) of the patients. However, only 38.5% (n=10) of these patients evaluated an improvement in their voice quality. Of all, 62.5% (n=25) of the patients reported no or only mild cough or voice hoarseness symptoms postoperatively, 22.5% (n=9) had moderate symptoms, and 15.0% (n=6) suffered from difficult supraesophageal symptoms. Ninety-five percent of the patients regarded the result of their surgery excellent, good, or satisfactory. Of all, 82.5% (n=33) of the patients would still choose surgery, 7.5% (n=3) would abstain from surgery, and 10% (n=4) of the patients were hesitant about their choice. For patients suffering from supraesophageal symptoms of gastro-esophageal reflux disease with objective evidence of pharyngeal acid exposure, laparoscopic Nissen fundoplication provides a good and alternative adding to current treatment.

Correlation between esophageal contraction amplitude and lower esophageal sphincter pressure in patients with nutcracker esophagus

Nutcracker esophagus (NE) is a primary esophageal motility disorder characterized by high-wave amplitude at the distal esophagus. The aim of this study was to analyze patients with NE and determine the relationship between distal esophageal contraction amplitude and lower esophageal sphincter (LES) pressure. Esophageal manometry tracings of patients with NE, defined as the presence of distal contraction amplitude of more than 182 mmHg after wet swallow, were analyzed. LES pressure was measured as the mean end-expiratory value. Spearman's correlation coefficient analysis was used to compare esophageal contraction amplitude with LES pressure. This comparison was also performed in patients with isolated hypertensive LES (HLES) and in subjects with normal manometry. Forty patients (25 female, 15 male; mean age 54 years) with NE were included in the study. Mean (SD) distal esophageal contraction amplitude was 230 (35.7) mmHg and mean LES pressure was 27.3 (5.7) mmHg. Esophageal contraction amplitude showed a positive correlation with LES pressure (r = 0.49, P < 0.01). In contrast, no correlation was found in patients with HLES (r = 0.21, P > 0.05) and in those with a normal manometric study (r = 0.18, P > 0.05). It is concluded that in patients with nutcracker esophagus a positive correlation exists between distal esophageal contraction amplitude and LES pressure, suggesting a diffuse hypertensive pattern involving smooth muscle at the distal esophagus and adjacent LES.

Obesity is associated with increased transient lower esophageal sphincter relaxation

BACKGROUND AND AIMS

Obesity has been associated with gastroesophageal reflux disease (GERD) and its complication, but the mechanism is unclear. We evaluated the association between obesity and function of lower esophageal sphincter (LOS) in subjects without GERD.

METHODS

We prospectively recruited consecutive obese (BMI >30) patients referred for weight reduction procedure and age- and sex-matched overweight (BMI 25-30) and normal weight (BMI > or =20 and <25) subjects. Exclusion criteria included esophagitis, reflux symptoms, use of proton pump inhibitor, hiatus hernia >2 cm, and diabetes mellitus with microvascular complication. All participants underwent combined 2-hour postprandial esophageal manometry and pH monitoring after a standard test meal followed by 24-hour ambulatory pH monitoring.

RESULTS

Eighty-four subjects (obese, 28; overweight, 28; normal weight, 28) were studied. All 3 groups had comparable mean LOS pressure, LOS length, and peristaltic function. During the postprandial period, both obese and overweight groups had substantial increase in 2-hour rate of transient lower esophageal sphincter relaxation (TLOSR) (normal weight: 2.1 +/- 1.2 vs overweight: 3.8 +/- 1.6 vs obese: 7.3 +/- 2.0, P < .001), proportion of TLOSR with acid reflux (normal weight: 17.6% +/- 22.0% vs overweight 51.8% +/- 22.5% vs obese: 63.5% +/- 21.7%, P < .001), and gastroesophageal pressure gradient (GOPG) (normal weight: 4.5 +/- 1.2 mm Hg vs overweight: 7.1 +/- 1.4 mm Hg vs obese: 10.0 +/- 1.5 mm Hg, P < .001). Using multiple regression model, BMI (r(2): 0.70, B: 0.28, 95% CI: 0.24-0.33, P < .001) and waist circumference (r(2): 0.65, unstandardized regression coefficient [B]: 0.10, 95% CI: 0.08-0.11, P < .001) were significantly correlated with TLOSR.

CONCLUSIONS

Obesity is associated with increased TLOSR and acid reflux during the postprandial period in subjects without GERD. Abnormal postprandial LOS function may be an early event in the pathogenesis of obesity-related GERD.

The effect of hydrocephalus on lower esophageal sphincter smooth muscle reactivity: experimental study

PURPOSE

The aim of this study was to assess the pharmacophysiological significance of the enteric nervous system for the mechanical responses of lower esophageal sphincter (LES) in infantile rats with kaolin-induced hydrocephalus.

MATERIAL AND METHODS

Hydrocephalus was created in 7-day-old rats by injection of kaolin into the cisterna magna. After 10 days, rats were decapitated. Contractile (KCl, carbachol) and relaxant (isoprenaline, papaverine) responses were determined by using in vitro muscle technique in isolated LES smooth muscle strips.

RESULTS

The receptor-mediated contractile and relaxant response to carbachol and isoprenaline in the LES smooth muscle was impaired in rats with hydrocephalus. There was no significant difference in the KCl and papaverine response in hydrocephalic and sham operated rats.

CONCLUSION

Our findings suggest that hydrocephalus may impair receptor-mediated contractile and relaxant activity of LES smooth muscle leading to gastroesophageal reflux.

Does an acute increase of intraabdominal pressure effect esophageal sphincter pressure?

BACKGROUND/AIMS

The study was designed to observe the acute alterations between lower esophageal sphincter (LES) and intraabdominal pressure (IAP) in patients undergoing diagnostic laparoscopy.

METHODOLOGY

Eleven patients (7 Male), aged 49 fitting the criteria for manometric research and diagnostic laparoscopy were studied. To measure the IAP in sterile conditions a new device (IAP measurement system) was set. Pressures at basal (b), during intraabdominal CO2 insufflations (min, m2, m3) and at the end of laparoscopy (me), were recorded simultaneously. All results were given as the difference between two maneuvers (A). Paired sample t-test was used.

RESULTS

The results were as follows; at the time of maximum CO2 insufflations: p delta m1-b; 24.25 vs. 14.64 mmHg, during the stabile insufflations: p delta m2-m1; -2.88 vs. 2.99 mmHg, p delta m3-m2; -0.70 vs. -0.82 mmHg and after deflation of CO2; end of the laparoscopy; p delta m(e)-m3; -16.73 vs. -16.65 mmHg for LESP and IAP respectively. The response of the LESP and IAP were similar in all phases (p > 0.05). Also alterations of pressures according to gender or presence of cirrhosis were found to be similar.

CONCLUSIONS

LESP is changed synchronously in the presence of acute pressure changes in IAP. Gender or presence of cirrhosis does not affect the response of LES.

Esophageal motility disorders in the morbidly obese population

BACKGROUND

Most studies investigating esophageal motility among the morbidly obese have focused on the relationship between lower esophageal sphincter (LES) pressure and gastroesophageal reflux disease (GERD). Very few studies in the literature have examined motility disorders among the morbidly obese population in general outside the context of GERD. This study aimed to determine the prevalence of esophageal motility disorders in obese patients selected for bariatric surgery.

METHODS

A total of 116 obese patients (81 women and 35 men) selected for laparoscopic gastric banding underwent manometric evaluation of their esophagus from January to March 2003. Tracings were retrospectively reviewed for the end points of LES resting pressure, LES relaxation, and esophageal peristalsis.

RESULTS

The study patients had a body mass index (BMI) of 42.9 kg/m2, and a mean age of 48.6 years. The following abnormal manometric findings were demonstrated in 41% of the patients: nonspecific esophageal motility disorders (23%), nutcracker esophagus (peristaltic amplitude >180 mmHg) (11%), isolated hypertensive LES pressure (>35 mmHg) (3%), isolated hypotensive LES pressure (<12 mmHg) (3%), diffuse esophageal spasm (1%), and achalasia (1%). Only one patient with abnormal esophageal motility reported noncardiac chest pain.

CONCLUSIONS

Despite a high prevalence of esophageal dysmotility in our morbidly obese study population, there was a conspicuous absence of symptoms. Although the patients in this study were not directly questioned with regard to esophageal symptoms, several studies in the literature support our conclusion.

The effect of laparoscopic partial fundoplication on dysphagia, esophageal and lower esophageal sphincter motility

It has been suggested that dysphagia is less common after partial versus complete fundoplication. The mechanisms contributing to postoperative dysphagia remain unclear. The objective of the present prospective study was to investigate esophageal motility and the prevalence of dysphagia in patients who have undergone laparoscopic partial fundoplication. Symptoms, lower esophageal sphincter (LES) characteristics and esophageal body motility were evaluated prospectively in 62 patients before and after laparoscopic partial fundoplication: 33 women and 29 men with a mean age of 44 +/- 1.5 years (range, 21-71). The patients filled in symptom questionnaires and underwent stationary and ambulatory manometry and 24-h pH-metry before and after operation. A small but significant increase in LES pressure from 14.8 +/- 0.9 to 17.8 +/- 0.8 mmHg was seen after laparoscopic partial fundoplication. Further, LES characteristics and esophageal body motility were not different post- versus preoperation. Three months after surgery, dysphagia was present in eight patients. No differences in LES characteristics or body motility were present between patients with and without dysphagia. Six months after the operation dysphagia was present in only three patients (3.2% mild and 1.6% severe dysphagia). Adequate reflux control was obtained in 85% of the patients. Laparoscopic partial fundoplication offers adequate reflux control without affecting esophageal body motility and with a very low incidence of postoperative dysphagia.

An experimental model of prolonged esophagitis with sphincter failure in the rat and the therapeutic potential of gastric pentadecapeptide BPC 157

We report a simple novel rat model that combines prolonged esophagitis and parallel sphincters failure. The anti-ulcer gastric pentadecapeptide BPC 157, which was found to be stable in gastric juice, and is being evaluated in inflammatory bowel disease trials, is an anti-esophagitis therapy that recovers failed sphincters. Twelve or twenty months after the initial challenge (tubes sutured into sphincters for one week and then spontaneously removed by peristalsis), rats exhibit prolonged esophagitis (confluent hemorrhagic and yellowish lesions, thinner epithelium and superficial corneal layer, with stratification derangement); constantly lowered pressure of both sphincters (assessed by using a water manometer connected to the drainage port of a Foley catheter implanted into the stomach either through esophageal or duodenal incision); and both lower esophageal and pyloric sphincter failure. Throughout the esophagitis experiment, BPC 157 was given at either 10 micro g/kg, i.p., once a day (last application 24 h before assessment) or alternatively, it was given continuously in drinking water at 0.16 micro g/ml (12 ml/rat). This treatment recovers i) esophagitis (macroscopically and microscopically, at either region or investigated time period) and ii) pressure in both sphincters (cmH2O). In addition, BPC 157 (10 micro g/kg) or saline (1 ml/rat, 5 ml/kg) was specifically given directly into the stomach; pressure assessment was performed at 5 min thereafter. The effect of BPC 157 is specific because in normal rats, it increases lower esophageal sphincter-pressure, but decreases pyloric sphincter-pressure. Ranitidine, given as the standard drug using the same protocol (50 mg/kg, i.p., once daily; 0.83 mg/ml in drinking water; or 50 mg/kg directly into the stomach) had no effect.

Anatomy of reflux: a growing health problem affecting structures of the head and neck

Gastroesophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR) are sibling diseases that are a modern-day plague. Millions of Americans suffer from their sequelae, ranging from subtle annoyances to life-threatening illnesses such as asthma, sleep apnea, and cancer. Indeed, the recognized prevalence of GERD alone has increased threefold throughout the 1990s. Knowledge of the precise etiologies for GERD and LPR is becoming essential for proper treatment. This review focuses on the anatomical, physiological, neurobiological, and cellular aspects of these diseases. By definition, gastroesophageal reflux (GER) is the passage of gastric contents into the esophagus; when excessive and damaging to the esophageal mucosa, GERD results. Reflux that advances to the laryngopharynx and, subsequently, to other regions of the head and neck such as the larynx, oral cavity, nasopharynx, nasal cavity, paranasal sinuses, and even middle ear results in LPR. While GERD has long been identified as a source of esophageal disease, LPR has only recently been implicated in causing head and neck problems. Recent research has identified four anatomical/physiological "barriers" that serve as guardians to prevent the cranial incursion of reflux: the gastroesophageal junction, esophageal motor function and acid clearance, the upper esophageal sphincter, and pharyngeal and laryngeal mucosal resistance. Sequential failure of all four barriers is necessary to produce LPR. While it has become apparent that GER must precede both GERD and LPR, the head and neck distribution of the latter clearly separates these diseases as distinct entities warranting specialized focus and treatment.

Long-term results of conventional myotomy in patients with achalasia: a prospective 20-year analysis

Myotomy has proved to be an efficient primary therapy in patients with achalasia, especially in younger patients (<40 years of age). The results of laparoscopic myotomy cannot be finally assessed, on account of the shorter postoperative follow-up. Thus, there are considerable data regarding intermediate-term outcomes after laparoscopic myotomy. The aim of our study was a 20-year analysis of the conventional cardiomyotomy as the underlying basis assessing the results of minimal-invasive surgery. Within 20 years (September 1985 through September 2005), 161 operations for achalasia were performed in our clinic. Enrolled in this study were 108 patients with a conventional, transabdominal myotomy in combination with an anterior semifundoplication (Dor procedure) and a minimal follow-up of 6 months. All patients were prospectively followed and, in addition to radiologic and manometric examinations of the esophagus, the patients were asked for their clinical symptoms by structured interviews in 2-year intervals. The median age at the time of surgery was 44.5 (range, 14-78) years, and 72.2% of the patients were males. The median length of the preoperative symptoms was 3 years (3 months to 50 years), and the postoperative follow-up was 55 (range, 6-206) months. In 70 (64.8%) patients, a pneumatic dilation had been performed. The preoperative Eckardt score of 6 (range, 2-12) could be reduced to 1 (range, 0-4) after myotomy (P<0.0001). Consequently, with 97.2% of all patients, a good-to-excellent result was achieved in the long-term follow-up, corresponding to a clinical stage I-II. Postoperatively, 69 patients (63.9%) gained weight. The radiologically measured maximum diameter of the esophagus decreased from preoperatively 45 (range, 20-75) mm to postoperatively 30 (range, 20-60) mm, while the minimum diameter of the cardia increased from 3.4 (range, 1-10) mm to 10 (range, 5-15) mm. The resting pressure of the lower esophageal sphincter could be reduced from 28.4 (range, 9.4-56.0) mm Hg to 8.6 (range, 3.0-22.5) mm Hg. Conventional myotomy leads in the long run with high efficiency to an improvement of the symptoms evident in achalasia. These results may be regarded as the basis for assessment of the minimal-invasive procedure.

Esophageal acid exposure in upright and recumbent postures: roles of lower esophageal sphincter, esophageal contractile and transport function, hiatal hernia, age, sex, and body mass

This study aimed to assess, using multiple regression analyses, the roles of lower esophageal sphincter, esophageal contractile and transport function, hiatal hernia, age, sex, and body mass for esophageal acid exposure in upright and recumbent postures and for esophagitis. In 116 patients with reflux symptoms, acid exposure was recorded by 24-hr pH monitoring, motility manometrically, bolus transport scintigraphically, hiatal hernia and esophagitis endoscopically. In upright posture, the percentage time at pH <4 increased significantly with higher body mass index and lower distal esophageal amplitude, the number of episodes >5 min at pH <4 with lower distal amplitude, slower transport, and higher body mass, and the longest episode at pH <4 with lower distal amplitude. In recumbency, the percentage time at pH <4 increased with lower percentage of effective esophageal contraction waves and male sex, and the number of episodes and the longest episode with lower percentage effective waves. The severity of esophagitis augmented with slower supine transport and male sex. In both postures, acid exposure and esophagitis seem to be determined primarily by impaired esophageal motility and the ensuing slow bolus transport rather than by compromised lower esophageal sphincter function and the presence and size of a hiatal hernia.

Review article: the management of achalasia - a comparison of different treatment modalities

BACKGROUND

Achalasia is an uncommon primary oesophageal motor disorder with an unknown aetiology. Therapeutic options for achalasia are aimed at decreasing the lower oesophageal sphincter pressure, improving the oesophageal empting, and most importantly, relieving the symptoms of achalasia. Modalities for treatment include pharmacologic, endoscopic, pneumatic dilatation and surgical. The decision of which modality to use involves the consideration of multiple clinical and economic factors.

AIM

To review the management strategies currently available for achalasia.

METHODS

A Medline search identified the original articles and reviews the published in the English language literature between 1966 and 2006.

RESULTS

The results reveal that pharmacotherapy, injection of botulinum toxin, pneumatic dilatation and minimally invasive surgical oesophagomyotomy are variably effective at controlling the symptoms of achalasia but that each modality has specific strengths and weaknesses which make them each suitable in certain populations. Overall, pharmacologic therapy results in the shortest lived, least durable response followed by botulinum toxin injection, pneumatic dilatation and surgery, respectively.

CONCLUSION

The optimal treatment for achalasia remains an area of controversy given our lack of complete understanding about the pathophysiology of the disease as well as the high numbers of clinical relapse after treatment. Further research focusing on optimal dosing of botulinum toxin injection and optimal timing of repeated graduated pneumatic dilatations could add to our knowledge regarding long-term therapy.

Injection of botulinum toxin before pneumatic dilatation in achalasia treatment: a randomized-controlled trial

BACKGROUND

Pneumatic dilatation is the first line therapy in achalasia, but half of patients relapse within 5 years of therapy and require further dilatations.

AIM

To assess whether botulinum toxin injection before pneumatic dilatation is superior to pneumatic dilatation alone in achalasia patients.

METHODS

Newly diagnosed achalasia patients were randomly assigned to receive botulinum toxin 1 month before pneumatic dilatation (botulinum toxin-pneumatic dilatation group: 27 patients with median age of 38) or to undergo pneumatic dilatation alone (pneumatic dilatation group: 27 patients with median age of 30). Response to therapy was assessed by clinical and objective methods at various intervals.

RESULTS

One-year remission rate of patients in botulinum toxin-pneumatic dilatation group was 77% compared with 62% in pneumatic dilatation group (P = 0.1). In pneumatic dilatation group, the oesophageal barium volume significantly (P < 0.001) decreased at 1 month, but this reduction did not persist over 1-year follow-up. Botulinum toxin-pneumatic dilatation group showed a significant (P < 0.001) reduction in barium volume at the various times intervals post-treatment. In the botulinum toxin-pneumatic dilatation group, 10/11 (91%) patients over 40 were in remission at 1 year, comparing with only five of nine (55%) cases in pneumatic dilatation group (P = 0.07).

CONCLUSION

Injection of botulinum toxin before pneumatic dilatation does not significantly enhance the efficacy of pneumatic dilatation.

Achalasia: physiology and etiopathogenesis

Achalasia is a disorder of esophageal motility that has been well documented for over 300 years. Despite this, the initiating factor or factors and the underlying mechanisms leading to the characteristic features of achalasia, the absence of distal esophageal peristalsis and abnormal lower esophageal sphincter relaxation, are still not well understood. Recent work has shed light on changes in neurotransmission and cell signaling in the lower esophagus and lower esophageal sphincter that lead to achalasia. A number of recent reviews have thoroughly discussed diagnostic and therapeutic modalities and the reader is referred to these for in-depth review of these topics. The focus of this review will be on our current understanding of the physiology of esophageal peristalsis and lower esophageal sphincter function as it relates to achalasia and on available evidence for etiology and proposed pathophysiologic mechanisms.

[Gastroesophageal reflux disease in hazardous drinkers]

Excess alcohol consumption has been associated with multiple pathologies of the gastrointestinal tract. The consumption of large amounts of alcohol (hazardous drinking) facilitates acid regurgitation by reducing the pressure of the lower oesophageal sphincter and slowing both oesophageal motility and gastric emptying. Regardless of the type of alcoholic beverage involved lower alcohol doses also have been shown to induce decreased pressure in lower oesophageal, decrease in oesophageal motility and enhanced risk of gastroesophageal reflux disease (GERD). GERD can be important risk factor for oesophageal adenocarcinoma. For identification of hazardous drinking patients we can use AUDIT (Alcohol Use Disorder Identification Test). AUDIT has been created by World Health Organization experts as a simple screening test looking for hazardous drinking people.

Effects of low-power argon plasma coagulation thermoablation of Barrett's epithelium on oesophageal motility

INTRODUCTION

Oesophageal dysmotility contributes to the pathogenesis of Barrett's epithelium (BE) allowing prolonged mucosal contact with injurious refluxate. Argon plasma coagulation (APC) is effective for BE ablation, but it is unknown whether the procedure affects oesophageal motility.

AIM

To assess the effect of low power (30 W) APC therapy on oesophageal motility in patients with BE.

METHODS

Thirty-three patients with at least 4 cm of BE underwent oesophageal manometry before and after APC ablation. All were on proton pump inhibitors. Oesophageal body peristaltic wave duration and amplitude, and lower oesophageal sphincter (LOS) pressure and length were compared before and after treatment.

RESULTS

In a total of 28 men and five women, with a mean age of 63.4 years (range 39-79) and mean BE length 6.5 cm (range 4-19), macroscopic clearance was achieved in 28 patients. A small statistically significant (P<0.05) increase in peristaltic wave amplitude was seen after APC [mean (SD) mmHg before versus after: 30.4 (15.2) versus 36.2 (20.1) at 13.5 cm, 47.6 (27.1) versus 54.5 (26.8) at 8.5 cm, and 51.2 (35.3) versus 58 (34.4) at 3.5 cm above the LOS]. No changes in either peristaltic wave duration or LOS parameters [mean (SD) pressure 10.6 (5.6) versus 10.3 (4.3) mmHg; length 2.8 (1.3) versus 2.8 (1.0) cm] were observed.

CONCLUSION

APC ablation of BE at a power setting of 30 W does not impair oesophageal motility.

Laparoscopic re-operation for failed Heller myotomy

Laparoscopic Heller myotomy for achalasia has a 10-20% failure rate and may require re-operation to control persistent or recurrent symptoms. We report follow-up of 15 patients who underwent laparoscopic re-operation for failed Heller myotomy. Between 1993 and 2004, 15 patients underwent laparoscopic re-operation for failed Heller myotomy at our center. The mean duration between procedures was 23 months. Follow-up was completed at a mean duration of 30 months in 14 patients (93%) via a telephone questionnaire. Our overall failure rate for primary surgery (n = 106) was 5.6%. The mechanisms of failure were incomplete myotomy (33%), myotomy fibrosis (27%), fundoplication disruption (13%), too tight fundoplication (7%) and a combination of myotomy fibrosis and incomplete myotomy (20%). Significant symptom improvement was observed with postoperative symptom resolution seen in 71% of patients with dysphagia, 89% for regurgitation, 58% for heartburn and 40% for chest pain. Fifty percent reported excellent results and 79% would recommend the procedure to a friend. Subsequent dilations were performed in four patients (29%). Two patients required conversion to open surgery (13%). Three patients (20%) failed the re-operation and required further revisional surgery. Complications included intraoperative perforation in three (none of which resulted in postoperative morbidity) and a pneumothorax in one patient. Prior endoscopic therapies (pneumatic dilation or Botulinum toxin) were not associated with poor results. Laparoscopic re-operation for failed Heller myotomy is feasible and results are encouraging.

Response of the lower esophageal sphincter to gastric distention by carbonated beverages

Gastroesophageal reflux disease often occurs in patients with normal resting pressure and length of the lower esophageal sphincter. Such patients often have postprandial reflux. The mechanism of postprandial reflux remains controversial. To further clarify this, we studied the effect of carbonated beverages on the resting parameters of the lower esophageal sphincter. Nine asymptomatic healthy volunteers underwent lower esophageal sphincter manometry using a slow motorized pull through technique after ingestion of tap water and carbonated beverages. Resting pressure, overall length, and abdominal length of the lower esophageal sphincter were measured. All carbonated beverages produced sustained (20 minutes) reduction of 30-50% in all three parameters of the lower esophageal sphincter. In 62%, the reduction was of sufficient magnitude to cause the lower esophageal sphincter to reach a level normally diagnostic of incompetence. Tap water caused no reduction in sphincter parameters. Carbonated beverages, but not tap water, reduce the strength of the lower esophageal sphincter. This may be relevant to the pathogenesis of gastroesophageal reflux disease, especially in Western society.

Physiology of reflux disease: role of the lower esophageal sphincter

The function of the lower esophageal sphincter (LES) has historically been elucidated by two major manometric methods: the one concentrating on static parameters including resting pressure, overall length, and intraabdominal length, and the other concentrating on the episodic loss of sphincter tone, termed "transient lower esophageal sphincter relaxations" (TLESRs). Both approaches yield valuable insights, but neither is all-encompassing. Both resting characteristics and the production of TLESRs are affected by many features in the typical western diet, including carbonated beverages. The authors hypothesize that repetitive distention resulting from such substances causes the LES to become transiently defective and reduces the threshold for the occurrence of TLESRs. Long-term defects of the resting parameters may reflect secondary damage to underlying muscle caused by increased reflux. The coexistence of hiatal hernia compounds the mechanical deficiency, and obesity also may contribute. Despite much research to reduce the frequency of TLESRs pharmacologically, restoration of the LES remains primarily within the realm of the surgeon.

Pharmacological targets in gastro-oesophageal reflux disease

Although proton pump inhibitors have become the mainstay of treatment in gastro-oesophageal reflux disease (GORD), there are still unmet needs in the management of this very common disorder. For example, all current proton pump inhibitors have a relatively slow onset of action and their activity is limited mainly to the post-prandial period with far less effective inhibition of nocturnal acid secretion. In order to achieve more potent, rapid and sustained acid inhibition several compounds are currently under development, such as new proton pump inhibitors with a prolonged plasma half-life, potassium competitive ATPase blockers (PCABs), histamine H3 agonists, and gastrin antagonists. Acid suppression does not, however, cure the disease and relapses are frequently observed after discontinuation of proton pump inhibitor therapy. Among the different abnormalities involved in the pathophysiology of this multifactorial disease, transient lower oesophageal sphincter relaxations represent the major mechanism responsible for episodes of reflux. Baclofen, the prototype GABA(B) receptor agonist, is one of the most potent inhibitors of transient lower oesophageal sphincter relaxations identified. To date the transfer of these relaxation-controlling pharmacological agents into clinical practice has however been hampered by the occurrence of unacceptable side effects. Beside "anti-relaxation therapy", the potential of novel prokinetics such as motilin agonists has been explored, especially since the motilin receptor has been cloned. Thus far the broad therapeutic value of prokinetics in GORD does, however, seem very limited in terms of efficacy with respect to oesophageal motility and acid exposure. Lastly, further research is necessary to better understand the complex mechanisms involved in oesophageal sensitivity and mucosal defence.

Esophageal motility disorders in diabetics with and without neuropathy

OBJECTIVE

To detect the presence of esophageal motor disorders in diabetic patients, and to establish whether there is any difference between patients with and without neuropathy.

METHODS

Fifty-six diabetic patients admitted at Department of Medicine at Ziauddin Medical University Hospital, Karachi were selected to observe if manometeric findings were different in diabetic patients with and without diabetic neuropathy.

RESULTS

Poor glycemic control was observed amongst patients with diabetic neuropathy as compared to those without neuropathy. Double peaked peristalsis and failure of peristalsis was more common in patients with diabetic neuropathy as compared to those without neuropathy. High amplitude and broader wave peristalsis and hypertensive lower esophageal sphincter was found in patients without neuropathy. Aperistalsis and multiple peaked waves were equally prevalent in patients with and without neuropathy.

CONCLUSION

Poor glycemic control was found in patients with diabetic neuropathy, double peaked and failed peristalsis was the most common manometric abnormality among them.

Lower esophageal sphincter analysis using computerized manometry in patients with chagasic megaesophagus

Due to the introduction of computer technology into manometry laboratories, three-dimensional manometric images of the lower esophageal sphincter can be constructed based on radially oriented pressures, a method termed 'computerized axial manometry.' Calculation of the sphincter pressure vector volume using this method is superior to standard manometric techniques in assessing lower esophageal sphincter function in patients with gastroesophageal reflux disease and idiopathic achalasia. Despite similarities between idiopathic achalasia and chagasic esophagopathy found using clinical, radiological, and manometric studies, controversy around lower esophageal sphincter pressure persists. The goal of this study was to analyze esophageal motor disorders in Chagas' megaesophagus using computerized axial manometry. Twenty patients with chagasic megaesophagus (5 men, 15 women, and average age 50.1 years, range 17-64) were prospectively studied. For three-dimensional imaging construction of the lower esophageal sphincter, a low-complacency perfusion system and an eight-channel manometry probe with four radial channels placed in the same level were used. For probe traction, the continuous pull-through technique was used. Results showed that the lower esophageal sphincter of patients with chagasic megaesophagus have significantly elevated pressure, length, asymmetry, and vector volumes compared to those of normal volunteers (P < 0.05). Aperistalsis of the esophageal body waves was observed in all patients and contraction amplitude was lower than that in normal patients. We conclude that patients with chagasic megaesophagus have hypertonic lower esophageal sphincter and aperistalsis of the esophageal body.

Laparoscopic partial myectomy

BACKGROUND

A number of different surgical procedures have been described for the treatment of gastroesophageal reflux disease. Moreover, modifications and completely new techniques are being introduced on a regular basis. Nonetheless, in most cases of novel laparoscopic techniques profound experimental data have not been collected prior to their clinical introduction. Due to the lack of an animal model of inadequate esophageal sphincter function, most experimental studies on antireflux procedures were done on normally functioning esophageal sphincters.

METHODS

It is well-known that myotomy alone cannot induce sphincter insufficiency in animal models. In addition, complete myectomy is associated with severe mortality and, therefore, is not useful as an experimental model. This study introduces a new model of laparoscopic partial in vivo myectomy. The procedure described here forms a myectomy of the esophagus using scissors and a sponge on the side of the greater gastric curvature. The size of the myectomy is approximately 6 x 1.5 cm and was successfully performed in a consecutive series of eight experimental animals (male German house pigs).

RESULTS

Following an intensive team training on dead animals, the procedure was performed with success via the laparoscope in all study animals (n = 8). The sphincter pressure as determined by manometry was significantly reduced from 7.7 mmHg (range, 4.5-9.1; preoperative values) to 2.2 mmHg (range, 0-6.8; early postoperative values) and 2.3 mmHg (range, 0-3.7) at 8 weeks after surgery (p < 0.001). In addition, the length of the lower esophageal sphincter as well as the sphincter pressure vector volume were significantly reduced early as well as at 8 weeks after laparoscopic myectomy. Furthermore, endoscopy and reflux testing were pathologic compared with control animals.

CONCLUSIONS

Laparoscopic partial myectomy results in complete sphincter insufficiency with only little procedure-related morbidity. This procedure allows for the experimental evaluation of surgical procedures on the gastroesophageal junction. Future modifications of surgical antireflux procedures can therefore be evaluated in an experimental setting prior to their clinical introduction.

The Effect of Esophageal and Gastric Distension on the Crural Diaphragm

BACKGROUND

The mechanism of prevention of gastric reflux into the esophagus is not exactly known. The lower esophagus has a barrier function provided by the lower esophageal sphincter. We investigated the hypothesis that the crural diaphragm shares in the barrier function not only mechanically but also actively through a crural-esophageal-gastric reflex action.

METHODS

The study was performed during repair of abdominal ventral and incisional hernias in 20 subjects (11 men, 9 women; age 38.6+/-4.8 years). The electromyographic response of the crural diaphragm to individual balloon distension of esophagus and stomach was recorded by means of a needle electrode inserted into the crural diaphragm and connected to an electromyographic apparatus. The recordings were repeated after separate crural, esophageal, and gastric anesthetization.

RESULTS

The crural diaphragm exhibited basal motor unit action potentials, which decreased on esophageal distension (P<0.001) after a mean latency of 17.3+/-2.8 SD ms. The crural diaphragm response to esophageal distension did not occur after the crural diaphragm or esophagus was anesthetized. Gastric distension effected an increase of crural diaphragm electromyographic activity with a mean latency of 18.4+/-4.6 ms; this effect could not be achieved after the crural diaphragm or stomach was anesthetized.

CONCLUSIONS

The crural diaphragm has a resting tone that relaxes after esophageal distension and contracts after gastric distension. This sphincter-like action of the crural diaphragm appears to be a reflex and is mediated through the esophagocrural inhibitory and gastrocrural excitatory reflexes. The crural diaphragm seems to share actively in the gastroesophageal competence mechanism.

Patients with multiple endocrine neoplasia type 1 with gastrinomas have an increased risk of severe esophageal disease including stricture and the premalignant condition, Barrett's esophagus

CONTEXT

Multiple endocrine neoplasia type 1 (MEN1) patients frequently develop Zollinger-Ellison syndrome (MEN1/ZES). Although esophageal reflux symptoms are common in these patients, little is known about long-term occurrence of severe peptic esophageal disease including strictures and Barrett's esophagus (BE).

OBJECTIVE

The objective of the study was to prospectively analyze the frequency of severe peptic esophageal disease in ZES patients with and without MEN1.

SETTING

The study was conducted at a tertiary care research center.

PATIENTS

Two hundred ninety-five patients (80 = MEN1/ZES, 215 = sporadic ZES) participated in a prospective study.

INTERVENTIONS AND OUTCOME MEASURES

Assessment of MEN1, acid hypersecretion, upper gastrointestinal endoscopy/biopsies, and tumor status were measured initially and at each follow-up. Esophageal manometry was performed in 89 patients. Frequency and type of esophageal disease were correlated with clinical/laboratory/tumoral features of ZES/MEN1.

RESULTS

In MEN1/ZES patients, esophageal stricture was 3-fold higher, BE 5-fold higher, and dysplasia 8-fold higher, and one patient died of esophageal adenocarcinoma. Esophageal symptoms were more frequent or severe in MEN1/ZES, but known risk factors for severe esophageal disease and ZES-specific features did not differ between MEN1/ZES and sporadic ZES. In MEN1/ZES, the onset of ZES was 10 yr earlier, and H2-antagonists were used longer and at lower doses. MEN1/ZES patients with esophageal disease differed from those without in that ZES diagnosis was delayed longer, esophageal symptoms were more frequent or severe, hiatal hernias were more frequent, esophagitis or pyloric scarring was more common, basal acid output was higher, and hyperparathyroidism was underdiagnosed.

CONCLUSIONS

This study shows that MEN1/ZES patients have a higher incidence of severe esophageal disease including the premalignant condition BE and identifies factors important for their pathogenesis that need to be incorporated into their long-term treatment.

The effect of chewing sugar-free gum on gastro-esophageal reflux

Regurgitated acid entering the mouth in gastro-esophageal reflux disease can cause dental erosion. Chewing gum could induce increased swallowing frequency, thus improving the clearance rate of reflux within the esophagus. The null hypothesis of this study was that chewing gum does not have any effect on the clearance of reflux from the distal esophagus. Thirty-one subjects presenting with symptoms of reflux were given a refluxogenic meal twice and were randomly selected to chew gum for half an hour after eating the meal. Esophageal pH was measured, and pH data were analyzed and compared during the postprandial periods for 2 hrs on the 2 occasions. The median (IQ range) values for the % time pH < 4 during the postprandial period without chewing gum were 5.7 (1.7-13.5) and, with chewing gum, 3.6 (0.3-7.3), respectively (p = 0.001). Chewing sugar-free gum for half an hour after a meal can reduce acidic postprandial esophageal reflux.

Effect of physical exercise on esophageal motility in patients with esophageal disease

The most common type of esophageal dysfunction associated with chest pain is gastroesophageal reflux, which may be induced by exercise. The effect of exercise on esophageal function has mainly been investigated in normal subjects or trained athletes. Few studies have investigated exercise and esophageal motility disorders. One hundred and thirty-five patients underwent ambulatory esophageal manometry and pH monitoring, before, during and immediately after moderate exercise. Patients were divided into four groups: Normal, nutcracker, diffuse spasm and gastroesophageal reflux disease (GERD). Ambulatory manometry and pH were monitored while exercising on a treadmill during which standardized boluses of water were administered. Nutcracker and diffuse spasm patients demonstrated a significant fall in esophageal wave amplitude during exercise compared to controls, which returned rapidly to pre exercise values after resting. There was no evidence of acid reflux in the non-reflux groups during exercise. Reflux was noted in 13 patients with GERD during exercise, none of whom had evidence of reflux at the onset of exercise. When these patients were classified by reflux type, the majority, 11 patients, were found to come from the combined or supine reflux group. Esophageal amplitude in nutcracker esophagus does not increase during moderate exercise. Moderate exercise provokes reflux in GERD patients with combined or supine reflux.

The relationship between extraesophageal reflux (EER) and obstructive sleep apnea (OSA)

Obstructive sleep apnea (OSA) and extraesophageal reflux (EER) are common chronic diseases and share several similar risk factors. The prevalence of gastroesophogeal (GERD) in OSA patients is significantly higher than the general population; however, no temporal or causal relationship has ever been demonstrated between the two. The purpose of this review is to understand the association between obstructive sleep apnea (OSA) and extraesophageal reflux disease (EER) in the adult population. We conclude that CPAP treatment of OSA significantly reduces GERD symptoms and acidic pH exposure in the esophagus and this improvement with CPAP physiologically occurs in the presence or absence of OSA; and treatment of GERD in OSA patients improves the number of arousals during sleep, but only one study showed a significant difference in apnea.

Incidence of Regurgitation after the Banded Gastric Bypass

BACKGROUND

Frequent regurgitation is a common complication following Roux-en-Y gastric bypass (RYGBP). This study investigated the risk of becoming a chronic regurgitator, by considering silicone ring size and lower esophageal sphincter (LES) function, and their relationship with weight loss.

METHODS

80 morbidly obese patients were randomly selected to undergo surgery using ring length of 62 mm (40 patients, group A) or 77 mm (40 patients, group B), with 6 months' postoperative follow-up. Preoperative esophageal manometry parameters were correlated with occurrence of chronic postoperative regurgitation. Patients were considered to present chronic regurgitation when this occurred on >10 days/month.

RESULTS

The groups were homogeneous regarding age, gender, race, weight, BMI (47.8+/-6.1 vs 50.2+/-6.4 kg/m2) and obesity-related diseases. There were 15% more chronic regurgitators in group A than in group B. Chronic regurgitators in group A lost more weight than chronic regurgitators in group B (P=0.026) or non-chronic regurgitators in group A (P=0.016). A greater proportion of chronic regurgitators had LES hypotonia (mean respiratory pressure <14 mmHg) than did non-chronic regurgitators (P=0.008). Logistic regression demonstrated that the chance of being a chronic regurgitator in group A was 4.5 times greater than in group B (P=0.046), and that the chance of a chronic regurgitator having LES hypotonia was seven times greater than of having normal LES pressure (P=0.006).

CONCLUSION

Silicone ring size and LES hypotonia are independent prognostic factors for chronic regurgitation following RYGBP. Ring size and chronic regurgitation contribute significantly towards weight loss during the first 6 postoperative months.

Gastric Electrical Stimulation (GES) with Parameters for Morbid Obesity Elevates Lower Esophageal Sphincter (LES) Pressure in Conscious Dogs

BACKGROUND

Treatment of obese patients with the implantable gastric stimulator (IGS) was reported to improve reflux symptoms, independent of weight loss. We evaluated the effect of gastric electrical stimulation on LES pressure in conscious dogs.

METHODS

8 dogs were studied. GES with three sets of parameters was randomly applied via a pair of electrodes implanted in the fundus on separate days. Manometry was performed with a Dent-Sleeve catheter passed through an esophageal canula. The involvement of the cholinergic pathway was also tested.

RESULTS

1) Stimulation with IGS parameters (40 Hz, 0.3 ms, 6 mA, 2 seconds on and 3 seconds off) induced a significant increase in LES pressure (29.9+/-4.8 mmHg), and remained significantly higher during the post-stimulation period (32.6+/-9.6 mmHg) compared to baseline (24.5+/-3.8 mmHg), P<0.01.2) Long pulse stimulation (10 cpm, 300 ms, 8 mA) tended to increase LES pressure from 29.6+/-4.4 mmHg of baseline to 31.8+/-4.9 mmHg with stimulation, to 32.6+/-4.5 mmHg after discontinuation (P=0.08); 3) Modified IGS parameters (40 Hz, 2 ms, 6 mA, 2 seconds on and 3 seconds off) did not induce a significant change in LES pressure during and after stimulation. 4) Effect of stimulation with IGS parameters on LES pressure was blocked by intravenous atropine.

CONCLUSION

GES with IGS parameters significantly increases LES pressure in conscious dogs. This effect is mediated by the cholinergic pathway. These results suggest that GES may be able to benefit GERD patients and obese patients with GERD.

Body mass index and chronic unexplained gastrointestinal symptoms: an adult endoscopic population based study

BACKGROUND

We aimed to determine whether obese subjects experience more gastro-oesophageal reflux (GORS) symptoms than normal subjects, and further to determine if this association was explained by oesophagitis or medications that lower oesophageal sphincter pressure.

METHODS

In a representative Swedish population, a random sample (n = 1001, mean age 53.5 years, 51% women) had upper endoscopy. GORS was defined as any bothersome heartburn or acid regurgitation.

RESULTS

The prevalence of obesity (body mass index > or =30) was 16%; oesophagitis was significantly more prevalent in obesity (26.5%) than in normal subjects (9.3%). There were associations between obesity and GORS (odds ratio (OR) 2.05 (95% confidence interval (CI) 1.39, 3.01)), epigastric pain (OR 1.63 (95% CI 1.05, 2.55)), irritable bowel symptoms (OR 1.58 (95% CI 1.05, 2.38)), any abdominal pain (OR 1.59 (95% CI 1.08, 2.35)), vomiting (OR 3.11 (95% CI 1.18, 8.20)), retching (OR 1.74 (95% CI 1.1.3, 2.67)), diarrhoea (OR 2.2 (95% CI 1.38, 3.46)), any stool urgency (OR 1.60 (95% CI 1.04, 2.47)), nocturnal urgency (OR 2.57 (95% CI 1.33, 4.98)), and incomplete rectal evacuation (OR 1.64 (95% CI 1.09, 2.47)), adjusting for age, sex, and education. When subjects with oesophagitis and peptic ulcer were excluded, only diarrhoea, incomplete evacuation, and vomiting were significantly associated with obesity. The association between GORS and obesity remained significant adjusting for medication use (OR 1.9 (95% CI 1.3, 3.0)).

CONCLUSIONS

GORS is associated with obesity; this appears to be explained by increased upper endoscopy findings in obesity.

Acoustic reflectometry esophageal profiles minimally affected by massive gas ventilation

Acoustic reflectometry can be used to distinguish between breathing tube placement in an esophagus vs the trachea via characteristic area-distance profiles for both cavities. In the cardiopulmonary resuscitation setting, capnography may be useless because the patient has little or no pulmonary circulation. With the breathing tube in the esophagus, can massive ventilation with a manual resuscitation bag, as might occur in the cardiopulmonary resuscitation setting, markedly alter the form of the obtained esophageal reflectometry profile? Nine hounds were induced, endotracheally intubated, mechanically ventilated, and anesthetized. Area-distance profiles were obtained with a 2-microphone acoustic reflectometer customized to measure areas up to 50 cm. Acoustic reflectometer profiles were obtained in intubated esophagi as follows: (1) baseline nonventilated state, (2) after aggressive 2-handed manual ventilation with high inspiratory pressures, rapid respiratory rates, and large tidal volumes for periods of 0.5, 1, and 1.5 minutes, upon detachment of the resuscitation bag, and (3) after esophagogastric decompression. We hypothesized that massive gas ventilation has no effect on the esophageal peak areas (null hypothesis), and used a paired t test for statistical significance (P < .05). For times of 0.5, 1.0, and 1.5 minutes, the ventilation volumes (mean +/- SD) were 25 +/- 7, 49 +/- 8, and 70 +/- 18 L. Massive gas ventilation caused minimal broadening and slight distal spread of the basal "hump". The mean peak area change was 0.18 +/- 0.35 cm2. For a paired t test (n = 9, df = 8), the corresponding t value was 1.54, with a P value of .16, which was incompatible with the null hypothesis. The experimental observations indicate a minimal effect of massive gas ventilation on the acoustic reflectometry esophageal profile. Hence, operator recognition of the altered canine acoustic reflectometer profile as that of an esophageal cavity is maintained, indicating that acoustic reflectometry may be useful in correctly identifying the site of breathing tube placement in out-of-hospital cardiac arrest situations despite massive esophageal ventilation.

Laparoscopic cardial calibration and gastropexy for treatment of patients with reflux esophagitis: pathophysiological basis and result

Laparoscopic antireflux surgery is the gold standard procedure for treatment of patients with reflux esophagitis. The current results of the laparoscopic approach are absolutely comparables with the results obtained during the open surgery era. The Nissen, Nissen-Rossetti, or Toupet techniques are the more frequently used. We have performed cardial calibration and posterior gastropexy or Nissen fundoplication by the open approach with similar results. The purpose of this article is to present the anatomo-physiological basis for employing cardial calibration and posterior gastropexy in patients with reflux esophagitis. This study includes 108 symptomatic patients, 12 of them with associated extraesophageal manifestations ( posterior laryngitis). Endoscopic mild or moderate esophagitis was confirmed in 83 patients, Barrett's esophagus in 12 patients, and type I or II hiatal hernia in 13 patients. All patients were also submitted to manometry, 24 hour intraesophageal pH monitoring, and barium swallow before and after surgery. Follow-up ranged from 12 to 36 months. There were no conversion, major intraoperative, or postoperative complications; nor were there any deaths. Postoperative dysphagia was present in 5% of cases. Symptomatic recurrence of reflux was observed in 10.3% and endoscopic presence of esophagitis in 12.3% of cases . Lower esophageal sphincter pressure increased significantly after surgery, even in patients with endoscopic recurrence. 24-hour intraesophageal monitoring improved after surgery, except in patients with objective recurrence of esophagitis. In conclusion, laparoscopic cardial calibration with posterior gastropexy presents comparable results to those reported after Nissen fundoplication and therefore could be another excellent therapeutic option in patients with reflux esophagitis.

On the pathogenesis of gastroesophageal reflux: The concept of gastroesophageal dyssynergia

OBJECTIVES

The cause of lower esophageal sphincter incompetence in gastroesophageal reflux disease is not clearly understood. We investigated the hypothesis that the esophagogastric junction incompetence results from failure of the gastric distention to produce the lower esophageal sphincter and crural diaphragm contraction caused by a disordered reflex action.

METHODS

The study was performed in 19 subjects (mean age, 42.6 +/- 7.2 years; 11 men and 8 women) who had reflux esophagitis and hiatus hernia and were scheduled for a fundoplication operation. Eight control volunteers (mean age, 41.8 +/- 6.9; 5 men and 3 women) who had huge supraumbilical ventral hernia but no reflux esophagitis or hiatus hernia were studied during operative hernia repair. The electromyographic activity and pressure response of the lower esophageal sphincter and crural diaphragm to separate esophageal and gastric distention were recorded.

RESULTS

In the control subjects (volunteers) esophageal distention caused diminished electromyographic activity of the crural diaphragm and lower esophageal sphincter with decreased esophagogastric junction pressure, whereas gastric distention increased the electromyographic activity of the crural diaphragm and lower esophageal sphincter with increased esophagogastric junction pressure. In the patients the crural diaphragm and lower esophageal sphincter showed diminished resting electromyographic activity, with either no response or a paradoxical response to esophageal or gastric distention.

CONCLUSION

The current study has demonstrated that the lower esophageal sphincter and crural diaphragm in patients with gastroesophageal reflux disease exhibited a diminished resting electric activity and either did not respond or reacted paradoxically to esophageal and gastric distention, constituting what we call esophagosphincteric and gastroesophageal paradox or dyssynergia. The cause of lower esophageal sphincter and crural diaphragm dysfunction is not known; a neurogenic cause was proposed. Further studies are required to investigate this point.