Relationship between partial gastric volumes and dyspeptic symptoms in fundoplication patients: a 3D ultrasonographic study

Postfundoplication retching: Strategies for management

BACKGROUND

Retching is a common symptom in children following antireflux surgery, particularly in those with neurodisability. There is now a strong body of evidence that implicates retching as a major cause of wrap breakdown. Retching is not a symptom of gastroesophageal reflux disease; it is a component of the emetic reflex. In addition to causing wrap breakdown, it is indicative of the presence of nausea. It is a highly aversive experience and warrants treatment in its own right.

METHODS

A framework was constructed for the management of postoperative retching, with strategies targeting different components of the emetic reflex. The impact of differing antireflux procedures upon retching was also considered.

CONCLUSIONS

Once treatable underlying causes have been excluded, the approach includes modifications to feeds and feeding regimens, antiemetics and motility agents. Neuromodulation and other, novel, therapies may prove beneficial in future. Children at risk of postoperative retching may be identified before any antireflux surgery is performed. Fundoplication is inappropriate in these children because it does not treat their symptoms, which are not because of gastroesophageal reflux, and may make them worse. They are also at risk of wrap disruption. Alternative strategies for symptom management should be employed, and fundoplication should be avoided.

LEVEL OF EVIDENCE

II-V.

Nissen fundoplication and dyspeptic symptoms: is the water load test useful?

BACKGROUND

The water load test is a simple, cheap and standardized method to evaluate gastric distension and gastric motility responses. We have previously shown that in patients with mild erosive or non-erosive esophagitis this test is frequently abnormal, suggesting an altered gastric function. The aim was to evaluate the water load test score before and after Nissen fundoplication in reflux patients.

METHODS

Thirty-one patients (16 men, 15 women, mean age 46.5 y) were studied before and 3 months after Nissen fundoplication by stationary esophageal manometry, wireless Bravo pH system monitoring (48 hours), and water load test. A dyspepsia symptom questionnaire was also completed before and after surgery. Data were compared with those of 35 controls.

RESULTS

All patients had pH-monitoring positive for pathological acid exposure and/or related-reflux symptoms in the absence of motility disorders. Basal symptoms scores were higher in patients compared to controls and improved after surgery, except than postprandial fullness, early satiation, and bloating, that were significantly increased. At baseline, all patients ingested significantly lower water volumes than controls, with a tendency to early onset of fullness and nausea, respectively. After surgery, the water volumes were significantly lower than presurgery.

CONCLUSIONS

In patients with reflux-related symptoms, with or without esophagitis, the water load test is frequently abnormal, suggesting an altered gastric function. Nissen fundoplication is associated with a relatively higher incidence of bloating, epigastric pain and fullness. These preliminary data could explain the incomplete resolution of symptoms after surgery in some patients, and suggest the use of additional studies to explore the gastric function in presurgical evaluation.

Clinical Predictors of Rapid Gastric Emptying in Patients Presenting with Dyspeptic Symptoms

BACKGROUND

Rapid gastric emptying (RGE) is defined as less than 30% retention at 1 h of solid meal ingestion. It is unclear whether RGE represents a separated clinical entity or part of the functional dyspepsia spectrum.

AIMS

To determine clinical predictors of RGE in patients presenting with dyspeptic symptoms.

METHODS

Retrospective study of patients who underwent solid Gastric Emptying Scintigraphy to evaluate dyspeptic symptoms from January 2011 to September 2012. Patients with delayed gastric emptying (> 10% gastric retention at 4 h) or prior gastric surgery were excluded. Patients with RGE were compared to those with normal gastric emptying (NGE) in a patient ratio of 1:3. Demographic data, symptoms, comorbidities, surgeries, endoscopy findings, medications, HbA1c, and TSH were analyzed. Univariate and multivariate logistic regression analyses were performed.

RESULTS

A total of 808 patients were included, 202 patients with RGE and 606 patients with NGE. Mean gastric retention at 1 h was 18% [12.0, 24.0] and 65% [52.0, 76.0], respectively. Patient with RGE were more likely to present with nausea/vomiting (OR 2.4, p < 0.001), weight loss (OR 1.7, p = 0.008), and autonomic symptoms (OR 2.8, p = 0.022). Identified clinical predictors of RGE were older age (OR 1.08 [1.01, 1.1], p = 0.018), male gender (OR 2.0 [1.4, 2.9], p ≤ <0.001), higher BMI (OR 1.03 [1.00, 1.05], p = 0.018), diabetes (OR 1.8 [1.2, 2.7], p = 0.05), and fundoplication (OR 4.3 [2.4, 7.7], p ≤ 0.001).

CONCLUSION

RGE represents a distinct population among patients presenting with dyspepsia in whom fundoplication, diabetes, and male gender were the strongest clinical predictors. RGE was significantly associated with nausea/vomiting, weight loss, and autonomic symptoms.

Evaluation of Gastric Volumes: Comparison of 3-D Ultrasound and Magnetic Resonance Imaging

To investigate gastric accommodation, accurate measurements of gastric volumes are necessary. An excellent technique to measure gastric volumes is dynamic magnetic resonance imaging (MRI). Unfortunately, dynamic MRI is expensive and not always available. A new 3-D ultrasound (US) method using a matrix transducer was developed to measure gastric volumes. In this prospective study, 14 healthy volunteers underwent a dynamic MRI and a 3-D US. Gastric volumes were calculated with intra-gastric liquid content and total gastric volume. Mean postprandial liquid gastric content was 397 ± 96.5 mL. Mean volume difference was 1.0 mL with limits of agreement of -8.9 to 10.9 mL. When gastric air was taken into account, mean total gastric volume was 540 ± 115.4 mL SD. Mean volume difference was 2.3 mL with limits of agreement of -21.1 to 26.4 mL. The matrix 3-D US showed excellent agreement with dynamic MRI. Therefore matrix 3-D US is a reliable alternative to measure gastric volumes.

Validation of a Novel 3-Dimensional Sonographic Method for Assessing Gastric Accommodation in Healthy Adults

OBJECTIVES

A novel automated 3-dimensional (3D) sonographic method has been developed for measuring gastric volumes. This study aimed to validate and assess the reliability of this novel 3D sonographic method compared to the reference standard in 3D gastric sonography: freehand magneto-based 3D sonography.

METHODS

A prospective study with 8 balloons (in vitro) and 16 stomachs of healthy volunteers (in vivo) was performed. After a 500-mL liquid meal, 1 preprandial and 3 postprandial volume scans of the stomachs were performed by the novel 3D sonographic method and the current reference-standard 3D sonographic method.

RESULTS

The in vitro study showed a mean volume difference between the novel method and the true balloon volume of -1.3 mL; limits of agreement (LoA) were small (-39.3 to12.3 mL), with an intraclass correlation coefficient (ICC) of 0.998. The in vivo study showed a mean gastric volume of 321 mL between the novel method and the freehand magneto-based method, with a mean volume difference of -4.4 mL; LoA were -40.1 to 31.2 mL, and the ICC was 0.991. The intraobserver and interobserver variability rates were low, at 0.8 mL (LoA, -24.0 to 25.6 mL), with an ICC of 0.995, and 0.5 mL (LoA, of -26.8 to 27.8 mL), with an ICC of 0.999, respectively.

CONCLUSIONS

The novel 3D sonographic method with automated acquisition showed good agreement with the current reference-standard gastric 3D sonographic method, with low intraobserver and interobserver variability. This novel 3D sonographic method is a valid and reliable technique for determining gastric accommodation.

Evaluation of gallbladder volume and contraction index with three-dimensional ultrasonography in healthy dogs

Three-dimensional (3D) ultrasonography has been shown to be an accurate and appropriate tool for measurement of gallbladder volume in humans. Therefore, we applied this novel technique for the first time to study fasting and postprandial gallbladder volume in 10 healthy dogs and compared the results with those of 2-dimensional (2D) ultrasonography. Fasting gallbladder volumes determined by 3D ultrasonography were significantly higher than corresponding volumes determined by 2D ultrasonography (P<0.01). Additionally, gallbladder volumes were significantly decreased in the postprandial state compared with the fasting state using 3D ultrasonography (P<0.001), but 2D ultrasonography showed no significant difference (P=0.189). The Gallbladder contraction index was higher in 3D ultrasonography than 2D ultrasonography; however, it did not reach statistical significance (P=0.25). In conclusion, 3D ultrasonography was able to measure gallbladder volume in healthy dogs in this study. It is suggested that 3D ultrasonography can be used to accurately estimate gallbladder volume and contractility.

Effect of proximal gastric volume on hiatal hernia

BACKGROUND

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

METHODS

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

KEY RESULTS

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

CONCLUSIONS & INFERENCES

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

Three-dimensional ultrasound imaging

This review is about the development of three-dimensional (3D) ultrasonic medical imaging, how it works, and where its future lies. It assumes knowledge of two-dimensional (2D) ultrasound, which is covered elsewhere in this issue. The three main ways in which 3D ultrasound may be acquired are described: the mechanically swept 3D probe, the 2D transducer array that can acquire intrinsically 3D data, and the freehand 3D ultrasound. This provides an appreciation of the constraints implicit in each of these approaches together with their strengths and weaknesses. Then some of the techniques that are used for processing the 3D data and the way this can lead to information of clinical value are discussed. A table is provided to show the range of clinical applications reported in the literature. Finally, the discussion relating to the technology and its clinical applications to explain why 3D ultrasound has been relatively slow to be adopted in routine clinics is drawn together and the issues that will govern its development in the future explored.

Functional evaluation at 1-year follow-up of laparoscopic Nissen-Rossetti fundoplication

Laparoscopic Nissen fundoplication is currently the gold standard for surgical treatment of gastroesophageal reflux disease. The aim of this study was to present our experience with this procedure at 1 year of follow-up. Forty patients were operated on between January 2006 and July 2007, and 30 underwent a 24-hour postoperative pH-metry study. Ninety-two percent of the patients were asymptomatic at a follow-up of 12 months. All pH-metric parameters improved. DeMeester and Johnson's score was reduced from 44.7 to 7.75; endoscopy with histologic samples revealed the healing of esophagitis in all patients; 4 (13%) patients complained of dysphagia, which resolved within 1 month after surgery. Twenty-seven (90%) patients were completely satisfied by their surgical results. One year after surgery, 24-hour ph-metric results show that laparoscopic Nissen fundoplication can completely control acid reflux with relatively few complications and a high degree of patient satisfaction.

Lack of relationship between chronic upper abdominal symptoms and gastric function in functional dyspepsia

To determine the relationship between gastric function and upper abdominal sensations we studied sixty FD patients (43 female). All patients underwent three gastric function tests: (13)C octanoic gastric emptying test, three-dimensional ultrasonography (proximal and distal gastric volume), and the nutrient drink test. Upper abdominal sensations experienced in daily life were scored using questionnaires. Impaired proximal gastric relaxation (23%) and a delayed gastric emptying (33%) are highly prevalent in FD patients; however, only a small overlap exists between the two pathophysiologic disorders (5%). No relationship was found between chronic upper abdominal symptoms and gastric function (proximal gastric relaxation, gastric emptying rate, or drinking capacity) (all P > 0.01). Proximal gastric relaxation or gastric emptying rate had no effect on maximum drinking capacity (P > 0.01). The lack of relationship between chronic upper abdominal sensations and gastric function questions the role of these pathophysiologic mechanisms in the generation of symptoms.

Effect of the 5-HT3 receptor antagonist, ondansetron, on gastric size in dyspeptic patients with impaired gastric accommodation

BACKGROUND

A reduction of gastric accommodation after a meal has been documented in patients with idiopathic dyspepsia. In these patients the administration of a 5-HT3 receptor antagonist may reduce some of the dyspeptic symptoms; it is not clear however, whether these drugs influence gastric adaptation to distension as well.

AIM

To evaluate the effects of the 5-HT3 receptor antagonist, ondansetron, on gastric distension after a liquid meal in dyspeptic patients with reduced gastric accommodation.

METHODS

Before and after a 500 ml water load, gastric accommodation (area of the proximal and distal stomach) was evaluated using real-time ultrasonography in 21 idiopathic dyspepsia patients and 26 healthy controls. In dyspeptic patients, the test was repeated twice: after the administration of placebo and after ondansetron 8 mg i.v. (in both cases, 15 min prior to the water load). Secondary outcomes were epigastric pain, fullness and nausea as assessed by a visual analogue scale at basal and after ondansetron.

RESULTS

Fasting gastric size was similar in dyspeptic and controls. Compared with controls, dyspeptic patients showed a statistically significant smaller area of the proximal stomach (14.7+/-1.2 cm(2) vs. 18.6+/-1.4 cm(2), respectively; p=0.0247). In dyspeptic patients, gastric proximal and distal size did not change significantly following placebo, whereas after the administration of ondansetron the mean area of the proximal and distal stomach significantly increased (proximal stomach: 14.6+/-1.6 cm(2) placebo, 20.4+/-1.9 cm(2) ondansetron, p=0.0095; distal stomach: 8.9+/-0.9 placebo, 11.4+/-1.2cm(2) ondansetron, p=0.0409). Of the symptoms, only nausea was significantly reduced after ondansetron.

CONCLUSION

In dyspeptic patients with impaired gastric accommodation, ondansetron reverts gastric accommodation to within the range of controls.

Use of antireflux medication after antireflux surgery

INTRODUCTION

It is claimed that a substantial number of patients who undergo antireflux surgery use antireflux medication postoperatively. This study was aimed to determine the prevalence and underlying reasons for antireflux medication usage in patients after surgery.

MATERIALS AND METHODS

A questionnaire on the usage of antireflux medication was sent to 1,008 patients identified from a prospective database of patients who had undergone a laparoscopic antireflux procedure.

RESULTS

A total of 844 patients (84%) returned the questionnaire. Mean follow-up was 5.9 years after surgery. A single or combination of medications was being taken by 312 patients (37%): 82% proton pump inhibitors, 9% H2-blockers and 34% antacids. Fifty-two patients (17%) had never stopped taking medication, whereas 260 patients (83%) restarted medication at a mean of 2.5 years after surgery. Return of the same (31%) or different (49%) symptoms were the commonest reasons for taking medication, whereas 20% were asymptomatic or had other reasons for medication use. Postoperative 24-hour pH studies were abnormal in 16/61 patients (26%) on medication and in 5/78 patients (6%) not taking medication.

CONCLUSIONS

Antireflux medication is frequently taken by many patients for various symptoms after antireflux surgery. Symptomatic patients should be properly investigated before antireflux medications are prescribed.

Drinking capacity and severity of dyspeptic symptoms during a water load test after Nissen fundoplication

Up to 30% of subjects undergoing Nissen fundoplication develop dyspeptic symptoms. Previous studies using the water load test have shown that functional dyspepsia patients have a diminished drinking capacity due to increased visceral sensitivity. Here we investigate drinking capacity and severity of symptoms in 9 patients with dyspeptic symptoms after fundoplication, 9 patients without symptoms after surgery, 18 functional dyspepsia patients, and 18 controls. The water load test was performed by having subjects drinking room-temperature tap water at a predetermined rate of 15 ml/min. The presence and severity of symptoms during the test were evaluated every 5 min using a Likert scale. We found that patients with dyspeptic symptoms after fundoplication had a significantly lower drinking capacity and higher symptoms scores than controls (P<0.05) but values similar to those of functional dyspepsia patients (P>0.05). In contrast, drinking capacity in patients without symptoms after surgery was similar to that in controls (P>0.05). These findings suggest that, as in functional dyspepsia, severe dyspeptic symptoms after Nissen fundoplication are associated with an impaired drinking capacity, reflecting visceral hypersensitivity or impaired gastric accommodation or both.

Measurements of gastric emptying of low- and high-nutrient liquids using 3D ultrasonography and scintigraphy in healthy subjects

Scintigraphy represents the 'gold standard' for the measurement of gastric emptying. Recent studies suggest that three-dimensional (3D) ultrasonography may allow a precise measure of gastric emptying, given the capacity for accurate volume calculations of the stomach. The aim of this study was to compare measurements of gastric emptying of both low- and high-nutrient drinks by 3D ultrasonography with scintigraphy. Ten healthy young subjects (6M, 4F, age 23.5 +/- 1.5 years) were studied on 2 days. Concurrent measurements of gastric emptying by scintigraphy and 3D ultrasonography were performed after ingestion of 500 mL beef soup (12 kcal) or 300 ml dextrose (25% w/v) (314 kcal) labelled with 20 MBq (99m)Tc-sulphur colloid. There was no significant difference between scintigraphic and ultrasonographic 50% emptying times (T50s) (soup: 27.7 +/- 4.8 min vs 23.8. +/- 4.8 min; dextrose: 122.2 +/- 13.3 min vs 131.9 +/- 10.2 min). There was a close correlation between scintigraphic and ultrasonographic T50s for both soup (r = 0.92, P = 0.0005) and dextrose (r = 0.88, P = 0.0007). For the T50s, the limits of agreement were -15.2 min and +8.1 min for the soup (mean difference -3.6 min) and -35.3 min and +47.6 min for dextrose (mean difference +6.2 min). 3D ultrasonography provides a valid measure of gastric emptying of liquid meals in healthy subjects.

Five-year subjective and objective results of laparoscopic and conventional Nissen fundoplication: a randomized trial

OBJECTIVE

The purpose of this prospective study was to compare the subjective and objective outcome of laparoscopic (LNF) and conventional Nissen fundoplication (CNF) up to 5 years after surgery as obtained in a multicenter randomized controlled trial.

SUMMARY OF BACKGROUND DATA

LNF is regarded as surgical treatment of first choice for refractory gastroesophageal reflux disease by many surgeons based on several short- and mid-term studies. The long-term efficacy of Nissen fundoplication, however, is still questioned as objective data gathered from prospective studies are lacking.

METHODS

From 1997 to 1999, 177 patients were randomized to undergo LNF or CNF. Five years after surgery, all patients were requested to fill in questionnaires and to undergo esophageal manometry and 24-hour pH-metry.

RESULTS

A total of 148 patients agreed to participate in the follow-up study: 79 patients after LNF and 69 after CNF. Of these, 97 patients (48 LNF, 49 CNF) consented to undergo esophageal manometry and 24-hour pH-metry. At 5 years follow-up, 20 patients had undergone reoperation: 12 after LNF (15%) and 8 after CNF (12%). There was no difference in subjective outcome, with overall satisfaction rates of 88% and 90%, respectively. Total esophageal acid exposure times (pH < 4) were 2.1% +/- 0.5% and 2.0% +/- 0.6%, respectively (P = 0.21). Antisecretory medication was taken daily in 14% and 16%, respectively (P = 0.29). There was no correlation between medication use and acid exposure and indices of symptom-reflux association (symptom index and symptom association probability). No significant differences between subjective and objective results at 3 to 6 months and results obtained at 5 years after surgery were found.

CONCLUSIONS

The effects of LNF and CNF on general state of health and objective reflux control are sustained up to 5 years after surgery and the long-term results of LNF and CNF are comparable. A substantial minority of patients in both groups had a second antireflux operation or took antisecretory drugs, although the use of those medications did not appear to be related to abnormal esophageal acid exposure.

The 5-HT4 antagonist R216073 does not affect gastric motor and sensory function in patients with functional dyspepsia

BACKGROUND

Serotonin and the 5-HT4 receptor play an important role in gastrointestinal motor and sensory functions. While 5-HT4 agonists are known for their prokinetics properties, the effect of 5-HT4 antagonists on upper gastrointestinal functions is largely unknown.

AIM

To assess the effect of a 5-HT4 receptor antagonist (R216073) on gastric relaxation and visceral sensitivity in patients with functional dyspepsia. Secondly, the influence of a functional polymorphism in the gene encoding the serotonin transport protein on drug response was determined.

METHODS

A double-blind, randomized, placebo-controlled, two-period crossover study was performed in 20 functional dyspepsia patients. The effect of a single dose of 2,000 mg R216073 on gastric relaxation and sensitivity was tested using three-dimensional ultrasonography and a nutrient drinktest.

RESULTS

R216073 did not affect partial gastric volumes or upper abdominal sensations scored during three-dimensional ultrasonography (P > 0.05). The maximum tolerated volume or upper abdominal sensations induced by the drinktest were not affected by R216073 (P > 0.05). The serotonin transport protein promoter polymorphism was not associated with any of the end-points of the study.

CONCLUSIONS

A single dose of R216073 had no effect on fundic relaxation, drinking capacity, or upper abdominal symptoms in patients with functional dyspepsia.

Partial gastric volumes and upper abdominal sensations in functional dyspeptic and GERD patients: a 3D ultrasonographic study

OBJECTIVES

The aim of the study was to evaluate the change in proximal and distal gastric volumes after ingestion of a nutrient drink and its relationship to upper abdominal sensations using three-dimensional ultrasonography.

METHODS

Fifty FD patients, 20 GERD patients patients and 35 healthy controls participated. Partial gastric volumes and sensations were assessed while fasting and after ingestion of a nutrient drink (500 mL, 300 kcal). Division of partial gastric volumes by total gastric volume was used to calculate proximal and distal gastric volume ratios.

RESULTS

The proximal gastric volume ratio was smaller in FD patients and larger in GERD patients compared to controls (p < 0.001 and p= 0.008, respectively). FD patients with impaired proximal relaxation (46%) had a larger increase in distal gastric volume (p= 0.008) and higher fullness sensations (p= 0.027) compared to FD patients with normal proximal relaxation. Fullness was related to distal gastric volume in both GERD patients and healthy controls (r= 0.761, p < 0.001 and r= 0.674, p= 0.001, respectively). In FD patients this relationship was not observed.

CONCLUSIONS

Impaired proximal gastric volume change after ingestion of a nutrient drink is associated with a larger distal gastric volume and increased fullness. In health and in GERD patients, the distal stomach is important in the regulation of fullness. However, in FD patients with normal or altered gastric volume distribution, this relationship is disturbed, implying that other causes are involved in the excessive generation of fullness.

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.