Transient Lower Esophageal Sphincter Relaxations and Gastroesophageal Reflux Episodes in Healthy Subjects and GERD Patients During 24 Hours

Still little is known about the 24-hr pattern of transient lower esophageal sphincter relaxations (TLESRs), particularly in patients with GERD. The aim of our study was to evaluate the 24-hr esophageal and LES motor pattern and esophageal pH and to identify the relationship between TLESRs and gastroesophageal reflux in healthy subjects and in GERD patients. Ten healthy subjects and nine patients with esophagitis (grade I–II) underwent a 24-hr pH manometric recording by means of a portable electronic device. The recording aimed at identifying the temporal relationships between reflux episodes and LES motor events. The GERD patients showed a greater number of either reflux episodes or TLESRs during the 24 hr as compared to controls. While most refluxes occurred during TLESRs in both groups, a small percentage of TLESRs was followed by reflux episodes in healthy people, with only a slight increase in GERD patients. In conclusion, although representing an important motor pattern during gastroesophageal reflux both in healthy subjects and in patients with GERD, TLESR could probably be considered one of the pathophysiologic mechanisms of gastroesophageal reflux more than the primary cause of reflux episodes.     

下食管括约肌运动和功能与胃食管反流病

目的　观察胃食管反流病 (GERD)患者与对照组餐前、餐后食管pH情况 ,下食管括约肌(LES )运动模式的变化以及酸反流事件与一过性下食管括约肌松弛 (TLESR )、低LES压力 (LESP)的关系。方法　两组受试者均接受连续性 4h食管压力测定 (分别为空腹和餐后 1、2、3h)和食管pH监测 (GERD组检测 4h ,对照组检测 2 4h)。结果　GERD组酸反流事件明显高于对照组 (P <0 0 5 )。两组间TLESR发生率差异无显著性 (P >0 0 5 ) ,但与空腹比较 ,两组餐后 1h和 2hTLESR发生率明显增多 ;GERD组伴有酸反流的TLESR明显高于对照组 (P <0 0 0 1)。 4 3% (2 9/ 6 8)的酸反流事件发生在TLESR期间。 31% (2 1/ 6 8)的酸反流事件出现于低LESP状态中。结论　GERD是多因素参与的病理过程。LES运动形式变化和功能不全是GERD的重要背景因素。     

Transient Lower Esophageal Sphincter Relaxations and Esophageal Body Muscular Contractile Response in Reflux Esophagitis

In patients with gastroesophageal reflux disease (GERD), transient lower esophageal sphincter relaxations (TLESRs) are more frequently accompanied by acid reflux than in normals. The role of esophageal tone during gastroesophageal reflux events is unknown. We studied the tonic motor activity in the body of the esophagus during TLESRs with and without acid reflux in 11 patients with erosive esophagitis and compared the results with those previously obtained in healthy subjects. Esophageal peristaltic contractions were recorded 13, 8, and 3 cm above a sleeve that measured LES pressure. An intraluminal balloon was inflated 8 cm above the sleeve to induce an esophageal tonic contraction [artificial high pressure zone (HPZ)]. The percentage of TLESRs with acid reflux was significantly higher in patients with esophagitis than in healthy controls (58.3% vs 37.3%, P < 0.05). TLESRs per se were not associated with an inhibition or increase in esophageal body contractility, which, however, changed substantially immediately after reflux. In patients with esophagitis the esophageal body tonic contractility was inhibited in 59.5% of TLESRs vs 36% in controls (P < 0.05). Esophageal contractions during TLESRs traveled down the esophagus in 77% of the instances in patients vs 96.5% in controls (P < 0.05). In conclusion, gastroesophageal reflux during TLESRs was more frequently associated with inhibition of esophageal body tonic contractility in patients with esophagitis than in normals. The different response of the esophageal body to reflux observed in GERD patients may partially contribute to the higher prevalence of reflux during TLESRs in these patients.     

Gastroesophageal reflux disease and baclofen: Is there a light at the end of the tunnel?

Transient lower esophageal sphincter relaxations (TLESRs) are rapid and prolonged relaxations of the lower esophageal sphincter (LES) that are not associated with swallowing. They are the mechanism by which most gastroesophageal reflux episodes occur in normal people and in patients with esophagitis. Transient LES relaxations appear to be mediated by a vagovagal reflex initiated by gastric distention. Baclofen is a γ -aminobutyric acid (GABA) derivative that inhibits the production of TLESRs by acting as a GABA_B receptor agonist at one or more loci along the vagovagal reflex arc. Animal and human studies suggest that baclofen decreases the number of reflux events and amount of esophageal acid exposure. Baclofen or another GABA_B receptor agonist may be clinically useful in treatment of gastroesophageal reflux disease.     

Transient lower esophageal sphincter relaxations are no more frequent in patients with gastroesophageal reflux disease than in asymptomatic volunteers

OBJECTIVES: Studies of the relative frequency of transient lower esophageal sphincter relaxations (TLESRs) in patients with gastroesophageal reflux disease and asymptomatic controls have revealed conflicting data. We have therefore studied the frequency of TLESRs and the frequency and mechanisms of acid reflux episodes in patients with gastroesophageal reflux disease and age- and sex-matched asymptomatic controls using standardized criteria. METHODS: Ten patients with symptomatic gastroesophageal reflux disease (four male, aged 50 [30-59] yr) and 10 asymptomatic matched volunteers (four male, aged 50 [32-59] yr) were studied. Esophageal, lower esophageal sphincter, and gastric manometric and esophageal pH readings were recorded for 1 h before and 1 h after a 200-kcal, 150 ml long-chain triglyceride meal. RESULTS: TLESR frequency increased after the meal in both volunteers (median 0 [range = 0-3] to 3 [0-8] per hour,p < 0.01) and patients (1 [0-6] to 2.5 [0-9] per hour, p = 0.08). There was no significant difference in the frequency of TLESRs between volunteers and patients. TLESRs were more likely to be associated with acid reflux in patients (65% vs 37%, p = 0.03), whereas volunteers were more likely to reflux gas or liquid without acid (30% vs 3.0%, p = 0.01). CONCLUSIONS: TLESRs are no more frequent in patients with gastroesophageal reflux disease than age- and sex-matched asymptomatic volunteers. However, when TLESRs occur in patients, they are twice as likely to be associated with acid reflux.     

Role of CCK(A) receptors in postprandial lower esophageal sphincter function in morbidly obese subjects

To reduce weight, some morbidly obese patients are treated with an intragastric balloon, often resulting in increased reflux symptoms. As transient lower esophageal sphincter relaxations (TLESRs) are the major mechanism underlying reflux and can be reduced by cholecystokinin-A (CCK_A) blockade, we hypothesized that the CCK_A-receptor antagonist loxiglumide could reduce gastroesophageal reflux in these subjects. Postprandial manometric studies were performed in 12 obese subjects during infusion of placebo or loxiglumide. Before balloon placement, loxiglumide did not significantly reduce the rate of TLESRs but attenuated the postprandial decrease in LES pressure. After 10 weeks of balloon treatment, loxiglumide significantly reduced the rate of TLESRs. Postprandial LES pressure was significantly increased, whereas the meal-induced decrease in LES pressure was absent. Neither loxiglumide nor balloon placement affected gastroesophageal reflux. In conclusion, CCK_A receptors play an important role in post-prandial LES pressure decrease and are involved in the reflex pathway underlying the triggering of TLESRs, at least after balloon placement.     

Relationship between straining, transient lower esophageal sphincter relaxation, and gastroesophageal reflux in children

OBJECTIVE: Physical straining such as deep inspiration or coughing may induce gastroesophageal reflux (GER) by overcoming feeble lower esophageal sphincter (LES) pressure. The role of straining as a provocant of GER has not been analyzed systematically in children. It was our aim to examine the contribution of straining to the occurrence of GER with particular attention to its relationship to transient LES relaxations, which are a major mechanism of the occurrence of GER in pediatric patients. METHODS: Concurrent esophageal manometry and pH monitoring was performed for 4 h postprandially in six children with esophagitis (age 9 months to 12 yr). Analysis was performed on isolated single strain episodes, defined as an increased intragastric pressure > 10 mm Hg. When a drop of esophageal pH < 4.0 was noted within 15 sec after any part of a strain, this strain was defined as related to the reflux episode. RESULTS: The median value of basal LES pressure was 10 mm Hg (range 1-18). In all, 134 analyzable strains and 87 analyzable reflux episodes were recorded. Isolated strains were associated with 20 reflux episodes (23%). Reflux was observed more frequently with strains that occurred during transient LES relaxations (12/40) than straining when the LES was contracted (8/94) (p < 0.01). Sustained strain (35%) and inspiratory strain (25%) were the major patterns of straining related to reflux. CONCLUSION: Straining provoked reflux infrequently and simultaneous occurrence of straining and transient LES relaxation was important in determining the occurrence of strain-related reflux in pediatric patients with reflux esophagitis.     

The role of excessive esophageal acid exposure in patients with gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD), especially reflux esophagitis (RE), is characterized by excessive esophageal acid exposure. Transient lower esophageal sphincter (LES) relaxation is the major mechanism of acid reflux episodes in both healthy subjects (HS) and patients with GERD. In the sitting position, where acid reflux episodes often occur, there is no difference in the frequency of transient LES relaxations between these two groups; however, in patients with GERD, at 5 cm above the LES, the proportion of acid reflux episodes during transient LES relaxations is significantly greater than in the HS group. This difference is considered to be one of the causes of excessive esophageal acid exposure in patients with GERD, but its cause is still unclear. A recent study, which investigated the proportion of acid reflux episodes during transient LES relaxations at 2 and 7 cm above the LES, showed that there was no difference at 2 cm above the LES between HS and patients with RE, but at 7 cm they were significantly greater in patients with RE than in HS. Evaluation of acid reflux at 2 cm above the LES is difficult to measure, but the proximal extent of refluxate could be one of the important factors of excessive acid esophageal exposure in patients with RE. Ineffective esophageal motility, found in patients with moderate to severe RE, impairs esophageal bolus clearance of acid, therefore both the proximal extent of refluxate and the delay of esophageal bolus clearance of acid could be major causes of excessive esophageal acid exposure. Hiatus hernia also causes acid reflux, due to its association with hypotensive LES, and also impairs esophageal bolus clearance of acid.     

Transient lower esophageal sphincter relaxation and the related esophageal motor activities

Transient lower esophageal sphincter (LES) relaxation (TLESR) is defined as LES relaxation without a swallow. TLESRs are observed in both of the normal individuals and the patients with gastroesophageal reflux disorder (GERD). However, TLESR is widely considered as the major mechanism of the GERD. The new equipments such as high resolution manometry and impedance pH study is helped to understand of TLESR and the related esophageal motor activities. The strong longitudinal muscle contraction was observed during development of TLESR. Most of TLESRs are terminated by TLESR related motor events such as primary peristalsis and secondary contractions. The majority of TLESRs are associated with gastroesophageal reflux. Upper esophageal sphincter (UES) contraction is mainly associated with liquid reflux during recumbent position and UES relaxation predominantly related with air reflux during upright position. The frequency of TLESR in GERD patients seems to be not different compared to normal individuals, but the refluxate of GERD patients tend to be more acidic during TLESR.     

Effect of laparoscopic partial fundoplication on reflux mechanisms

OBJECTIVES: Transient lower esophageal sphincter relaxations (TLESRs) are the main mechanism causing gastroesophageal reflux. Since 1994 we have performed laparoscopic partial instead of complete fundoplication as standard surgical treatment for therapy resistant reflux disease to minimize postoperative dysphagia. To better understand the management of gastroesophageal reflux, we conducted a prospective study of the effects of laparoscopic partial fundoplication on TLESRs and other reflux mechanisms. METHODS: From 1994 to 1999, 65 patients underwent laparoscopic partial fundoplication (180-200 degrees) and 28 of these patients (16 female, 12 male, mean age 43 +/- 2 yr [range, 26-66 yr]) agreed to participate in this prospective study on reflux mechanisms. Before and 6 months after surgery, all patients were evaluated by simultaneous recording of pH and lower esophageal sphincter characteristics, using sleeve manometry. RESULTS: After partial fundoplication basal LES pressure increased significantly (p < 0.05), from 14.3 +/- 1.2 mm Hg to 17.8 +/- 1 mm Hg. Partial fundoplication significantly (p < 0.05) decreased the number of TLESRs, from 3.4 +/- 0.8 to 1.6 +/- 0.3 per hour in the fasting period, and from 4.7 +/- 0.5 to 1.9 +/- 0.3 per hour postprandially. The percentage of TLESRs associated with reflux also decreased significantly (p < 0.05), from 45 +/- 7% to 27 +/- 6% after operation. The number of reflux episodes decreased significantly (p < 0.05), from 4.1 +/- 0.7 to 1.3 +/- 0.3 per hour postoperatively. The majority of these episodes were associated with TLESRs: 57% and 46%, pre- and postoperatively, respectively. CONCLUSIONS: Laparoscopic partial fundoplication significantly increased fasting and postprandial LES pressure and significantly decreased TLESR frequency. This resulted in a significant reduction in esophageal acid exposure, with preservation of postprandial LES characteristics.     

The role of transsphincteric pressure and proximal gastric volume in acid reflux before and after fundoplication

BACKGROUND & AIMS: This study was conducted to explore the role of proximal gastric volume and transsphincteric pressure on acid reflux during transient lower esophageal sphincter relaxation (TLESR) in patients with gastroesophageal reflux disease (GERD) both before and after laparoscopic fundoplication. METHODS: Twenty GERD patients were studied before and after fundoplication along with 20 healthy controls. High-resolution manometry and pH recording was performed for 1 hour before and 2 hours following meal ingestion (500 mL/300 kcal). Three-dimensional ultrasonographic images of the stomach were acquired before and every 15 minutes after meal ingestion. RESULTS: Postprandial proximal to total gastric volume distribution ratios were significantly larger in GERD patients before fundoplication (0.57 +/- 0.01; P < .05) and smaller following fundoplication (0.37 +/- 0.01; P < .001) compared with controls (0.46 +/- 0.01). The percentage of TLESRs associated with acid reflux did not relate to proximal gastric volume in any subject group. The transsphincteric pressure profile was different for TLESRs with and without reflux in GERD patients as well as in healthy controls. The pressure gradient across the esophagogastric junction (EGJ) (DeltaEGJp) was greater for TLESRs with acid reflux compared with TLESRs without acid reflux in both GERD patients (11.4 +/- 0.8 vs 8.0 +/- 0.5 mm Hg, respectively; P < .01) and controls (10.6 +/- 0.7 vs 7.1 +/- 0.8 mm Hg, respectively; P < .05). After fundoplication, DeltaEGJp during TLESRs was 7.9 +/- 0.9 mm Hg, and the transsphincteric pressure profile markedly changed. CONCLUSIONS: Although proximal gastric volume plays a key role in eliciting TLESRs, it is not related to the incidence of acid reflux during TLESRs. The transsphincteric pressure gradient is greater in TLESRs associated with acid gastroesophageal reflux.     

Upright versus supine reflux in gastroesophageal reflux disease

BACKGROUND: Postural measures are early recommendations in the management of heartburn, and are aimed at preventing acid reflux through an incompetent lower esophageal sphincter (LES). However, LES incompetence is found in only a minority of patients, and transient LES relaxations, primarily in the upright position, are currently recognized as the main pathophysiological abnormality in gastroesophageal reflux disease (GERD). We investigated the importance of supine acid reflux in patients with GERD. METHODS: Upon review of their clinical, manometric, pH monitoring and endoscopic characteristics, 85 patients with reflux symptoms were classified into three groups: Group A (n=22), consisting of symptomatic patients without esophagitis or pathological reflux; group B (n=38), symptomatic patients with reflux but no endoscopic esophagitis; and group C (n=25), symptomatic patients with both ulcerative or complicated esophagitis and pathological reflux. RESULTS: All groups were similar in age distribution. Groups B and C had a higher prevalence of hiatal hernia and reflux symptoms. Manometry revealed similar LES pressures in groups A and B, but lower LES pressure in group C (P < 0.005). In groups A and B, supine reflux, in terms of percentage of time with pH < 4, was less pronounced than upright reflux (P < 0.0001). In contrast, group C supine reflux was as pronounced as the upright reflux. CONCLUSIONS: The majority of patients reflux in the upright position. Only patients with complicated esophagitis have significant bipositional acid reflux. These findings suggest that unless the patient has severe reflux disease, postural measures may not be indicated.     

Determinants of gastroesophageal junction incompetence: hiatal hernia, lower esophageal sphincter, or both?

OBJECTIVE: To examine the effects of hiatal hernia and lower esophageal sphincter (LES) pressure on the competence of the gastroesophageal junction under conditions of abrupt increases in intra-abdominal pressure. DESIGN: Acute experiments. SETTING: University-hospital-based gastroenterology practice. PARTICIPANTS: Sixteen asymptomatic volunteers and 34 patients with endoscopic findings suggestive of hiatal hernia. INTERVENTION: A series of eight provocative maneuvers entailing abrupt changes in intra-abdominal pressure. MEASUREMENTS: Five radiographic measurements relevant to the presence and extent of hiatal hernia were made from videotaped barium-swallow examinations. Lower esophageal sphincter pressure was measured immediately before each maneuver. The percentage of maneuvers that resulted in gastroesophageal reflux was calculated as the reflux score. A stepwise regression analysis was then used to model the relation between measured variables of the gastroesophageal junction (manometric and radiographic) with reflux score. RESULTS: Patients with hiatal hernia had substantially higher reflux scores and lower LES pressures than either patients without hernias or volunteers. In diminishing order of significance, the terms in the model of susceptibility to reflux were axial length of hernia measured between swallows; LES pressure; and an interaction term in which a progressive increase occurred in the risk for reflux associated with a hypotensive lower esophageal sphincter as hernia size increased. CONCLUSIONS: Gastroesophageal junction competence during abrupt increases in intra-abdominal pressure is compromised by both hiatal hernia and low LES pressure. These factors interact with each other to determine susceptibility to reflux.     

Study of the influence of hiatus hernia on gastroesophageal reflux

AIM: To explore whether the presence of a sliding hiatus hernia influences gastroesophageal reflux.METHODS: Endoscopy and 24 h pH monitoring were performed for 197 outpatients with gastroesophageal reflux symptoms.RESULTS: Of the 197 patients with symptoms of gastroesophageal reflux, patients with hiatus hernia accounted for 36%. The incidence of esophagitis in patients with hiatus hernia was significantly higher than that in patients without hiatus hernia. The results of 24 h pH monitoring showed that 84 patients had physiological reflux, 37 had pathological reflux without esophagitis, 64 had reflux esophagitis and 12 had physiological reflux concomitant with esophagitis. All the patients with hiatus hernia had a longer percentage time with supine reflux and a higher frequency of episodes lasting over 5 min at night compared to those without hiatus hernia. The incidence of combined daytime and nocturnal reflux in patients with hiatus hernia was significantly higher than that in patients without hiatus hernia.CONCLUSION: Pathological reflux and reflux esophagitis in some patients with symptoms of gastroesophageal reflux represent two different stages of gastroesophageal reflux disease. Pathological reflux is the first stage, in which the lower esophageal sphincter is incompetent but the esophageal mucosal resistance effectively prevents regurgitated acid from damaging the esophageal mucosa. Reflux esophagitis represents the second stage, in which the aggression of the regurgitated acid is so strong that the esophageal mucosa fails to resist it and the epithelium of the esophagus is damaged. Patients with hiatus hernia have a high incidence of combined daytime and nocturnal reflux, with the latter being responsible for esophagitis.     

Mechanisms underlying excessive esophageal acid exposure in patients with gastroesophageal reflux disease

The cause of reflux esophagitis (RE) is excessive esophageal acid exposure. Acid reflux and acid clearance after acid reflux are important factors related to excessive esophageal acid exposure. The main mechanism responsible for acid reflux is transient lower esophageal sphincter relaxation (TLESR), which is LES relaxation not associated with swallowing, and acid reflux caused by low LES pressure is rare. The frequency of TLESR in the postprandial period does not significantly differ between healthy subjects and gastroesophageal reflux disease (GERD) patients; however, the proportion of acid reflux episodes during TLESR is significantly higher in GERD patients. The layer of acid that appears above the dietary layer immediately below the esophagogastric junction (acid pocket) is attracting increasing attention as a cause of the difference in the proportion of acid reflux episodes during TLESR. The proportion of acid reflux episodes during TLESR is significantly higher when the acid pocket is present in the hernia sac than when it is located below the diaphragm. The acid pocket also shows upward migration and reaches the esophageal side of the esophagogastric junction, and the acid pocket itself has been suggested to cause mucosal damage in the lower esophagus. The amplitude and success rate of primary peristalsis decreases with increases in the severity of RE, leading to excessive esophageal acid exposure. Furthermore, the success rate of secondary peristalsis is lower in GERD patients than in healthy subjects.     

Effect of intragastric volume and osmolality on mechanisms of gastroesophageal reflux in children with gastroesophageal reflux disease

OBJECTIVE: Both transient lower esophageal sphincter (LES) relaxations (TLESRs) and periods of low/absent LES pressure (LESP) are the main mechanisms of gastroesophageal reflux. These events are believed to be triggered by stimuli from different areas of the upper GI tract. We aimed at investigating the relationship between LESP profile and gastric emptying and distension after meals of different composition in 30 children with gastroesophageal reflux disease (median age 7.0 yr, range 12 months-12 yr). METHODS: Recordings of LESP and intraesophageal pH for 1 h fasting and for 2 postprandial h were performed with a perfused sleeve catheter and flexible electrode, respectively; gastric emptying and distension of antral area were simultaneously recorded with real-time ultrasonography. Ten patients had a standard meal (group A), 10 had a high-volume meal (group B), and 10 had a high-volume and osmolality meal (group C). RESULTS: Postprandial esophageal acid exposure was significantly higher in patients of groups B and C than in patients of group A (p < 0.01); it was also more prolonged in patients of group C than in subjects of group B (p < 0.05). A higher postfeeding rate of reflux episodes caused by TLESRs was detected in patients of groups B and C as compared with patients of group A (p < 0.01). This increase did not statistically differ in patients of groups B and C. Patients of group C exhibited a higher postprandial rate of reflux episodes associated with low/absent tone of the LES as well as a more prolonged gastric emptying time and a higher postfeeding gastric distension as compared with patients of groups A and B (p < 0.01). Finally, a significant correlation was only found between the postprandial rate of reflux events resulting from low/absent LESP and the degree of antral distension in patients of group C (p < 0.01). CONCLUSION: Gastroesophageal reflux is worsened by increasing the volume and osmolality of meals through significant changes of LESP. Meals of high volume and meals with high volume and osmolality cause a comparable increase of reflux episodes as a result of TLESRs. However, meals with high volume and osmolality cause the higher degrees of esophageal acid exposure than meals with high volume resulting from a higher rate of reflux episodes associated with low/absent LESP. This finding correlates with a high postfeeding antral distension.     

Effect of prolonged gastric distention on lower esophageal sphincter function and gastroesophageal reflux

OBJECTIVES: Morbidly obese patients treated with an intragastric balloon report a transient increase in gastroesophageal reflux (GER) symptoms. In the present study, we evaluated the underlying mechanisms of GER and examined the effect of prolonged gastric distention on lower esophageal sphincter function. METHODS: Fasting and postprandial manometric studies were performed in obese subjects (n = 15) before, immediately after, and 10 and 20 wk after placement of a 500-ml water-filled balloon. RESULTS: Residual lower esophageal sphincter (LES) pressure after water swallows was not affected after balloon placement, excluding mechanical interaction with sleeve function. Postprandial LES pressure was significantly increased after 10 and 20 wk. GER was increased in the right recumbent position until 10 wk after balloon placement, mainly because of an increased percentage of transient lower esophageal sphincter relaxations (TLESRs) accompanied by GER. TLESRs were the main mechanisms underlying reflux both before and after balloon placement. The rate of TLESRs was increased significantly immediately after introduction of the balloon, returning to baseline values after 20 wk. After balloon placement, reflux episodes were evoked by gastric contractions that were not inhibited by meals. CONCLUSIONS: Chronic distention by an intragastric balloon increased reflux up to 10 wk after placement because of an increase in the percentage of TLESRs accompanied by a reflux episode. In addition, prolonged balloon distention increased the rate of TLESRs and created a postprandial state even 10 wk after balloon placement. After 20 wk these effects largely resolved, illustrating adaptation to this artificial situation.     

Acid-induced esophageal shortening in humans: a cause of hiatus hernia?

BACKGROUND: Hiatus hernia and gastroesophageal reflux disease commonly coexist, and there is pathophysiological evidence that the presence of a hiatus hernia contributes to abnormal acid reflux. However, the cause of hiatus hernia remains unclear. In an animal model, it has been shown that acute acid injury to the esophagus results in esophageal shortening, raising the possibility that reflux esophagitis per se can contribute to the formation of hiatus hernia by inducing esophageal shortening. AIM: To determine whether luminal acid produces esophageal shortening in humans. METHODS: Twelve volunteers were each studied on two occasions, one week apart, in a double-blind, crossover trial. The location of the lower esophageal sphincter (LES), as well as the LES resting pressure and axial length were determined at baseline and then again after 20 min of either acid or saline perfusion. RESULTS: Acid perfusion did not induce significant changes in resting LES pressure but resulted in proximal migration of the LES (ie, esophageal shortening) by an average of 0.5 cm, with the largest proximal migration being 1.8 cm. In contrast, saline perfusion resulted in slight distal migration of the LES (ie, esophageal lengthening). CONCLUSIONS: Intraluminal acid perfusion causes longitudinal axis shortening of the esophagus and suggests that gastroesophageal acid reflux may contribute to the cause of hiatus hernia.     

Gastroesophageal reflux and gastric emptying,revisited

Total gastric emptying is delayed in 10% to 33% of adult patients with gastroesophageal reflux disease (GERD), but a strong correlation between duration of gastric emptying and severity of acid reflux or esophagitis has never been proved. Previous studies reported that patients with GERD might have exaggerated postprandial fundus relaxation with retention of food and triggering of transient lower esophageal sphincter relaxations (TLESRs). There is a positive correlation between postprandial fundus relaxation and number of TLESRs and also between proximal gastric emptying and esophageal acid exposure. However, new studies suggest that a high number of TLESRs and reflux events may occur even with accelerated gastric emptying, and prolonged gastric retention might be associated with less rather than more esophageal acid exposure. Using simultaneous gastric emptying and esophageal pH impedance we found that the rate of gastric emptying might determine the acidity and proximal extent of reflux: The slower the emptying, the higher the pH and proximal extent of the refluxate.     

Esophageal manometric changes and gastroesophageal reflux symptoms after distal gastrectomy for gastric cancer

BACKGROUND/AIMS: Gastroesophageal reflux is known to be a common complication after gastrectomy. However, its mechanism is not completely understood. We investigated the effects of distal gastrectomy for gastric cancer on the lower esophageal sphincter (LES) and esophageal motility. METHODOLOGY: In 18 patients who underwent distal gastrectomy reconstructed with Billroth I method for gastric cancer, esophageal motility and LES function were evaluated by means of a low-compliance manometric system. The LES pressure was determined by a rapid pull-through technique. Endoscopy before and after operation determined presence or absence of esophagitis and hiatus hernia. RESULTS: No significant differences were observed in esophageal contractile amplitudes before and after distal gastrectomy. After distal gastrectomy, five patients had reflux symptoms of heartburn and regurgitation; 11 had none. Endoscopy revealed esophagitis after distal gastrectomy in two patients with reflux symptoms and one patient without reflux symptoms. The LES pressure in patients with reflux symptoms decreased significantly after distal gastrectomy (before gastrectomy: 26.1 +/- 1.1 mmHg, after distal gastrectomy: 15.3 +/- 3.5 mmHg, p<0.05). There was no significant change in patients without reflux symptoms. CONCLUSIONS: This study demonstrated that LES pressure after distal gastrectomy in patients with reflux symptoms was significantly lower than that before gastrectomy. This result suggested that LES pressure decrease plays an important role in development of gastroesophageal reflux after distal gastrectomy reconstruction with the Billroth I method.