Anatomy and mechanical properties of the anal sphincter muscles in healthy senior volunteers

BACKGROUND

A large proportion of age-related fecal incontinence is attributed to weakness or degeneration of the muscles composing the anal continence organ. However, the individual role of these muscles and their functional interplay remain poorly understood.

METHODS

This study employs a novel technique based on the combination of MR imaging and FLIP measurements (MR-FLIP) to obtain anatomical and mechanical information simultaneously. Unlike previous methods used to assess the mechanics of the continence organ, MR-FLIP allows inter-individual comparisons and statistical analysis of the sphincter morpho-mechanical parameters. The anatomy as well as voluntary and involuntary mechanical properties of the anal continence organ were characterized in 20 healthy senior volunteers.

RESULTS

Results showed that the external anal sphincter (EAS) forms a funnel-like shape with wall thickness increasing by a factor of 2.5 from distal (6 ± 0 mm) to proximal (15 ± 3 mm). Both voluntary and involuntary mechanical properties in this region correlate strongly with the thickness of the muscle. The positions of least compliance and maximal orifice closing were both located toward the proximal EAS end. In addition, maximal contraction during squeeze maneuvers was reached after 2 s, but high muscle fatigue was measured during a 7 s holding phase, corresponding to about 60% loss of the energy produced by the muscles during the contraction phase.

CONCLUSIONS

This work reports baseline parameters describing the morpho-mechanical condition of the sphincter muscle of healthy elderly volunteers. New parameters were also proposed to quantify the active properties of the muscles based on the mechanical energy associated with muscle contraction and fatigue. This information could be used to assess patients suffering from AI or for the design of novel implants.

Ambulatory reflux monitoring for diagnosis of gastro-esophageal reflux disease: Update of the Porto consensus and recommendations from an international consensus group

BACKGROUND

An international group of experts evaluated and revised recommendations for ambulatory reflux monitoring for the diagnosis of gastro-esophageal reflux disease (GERD).

METHODS

Literature search was focused on indications and technical recommendations for GERD testing and phenotypes definitions. Statements were proposed and discussed during several structured meetings.

KEY RESULTS

Reflux testing should be performed after cessation of acid suppressive medication in patients with a low likelihood of GERD. In this setting, testing can be either catheter-based or wireless pH-monitoring or pH-impedance monitoring. In patients with a high probability of GERD (esophagitis grade C and D, histology proven Barrett's mucosa >1 cm, peptic stricture, previous positive pH monitoring) and persistent symptoms, pH-impedance monitoring should be performed on treatment. Recommendations are provided for data acquisition and analysis. Esophageal acid exposure is considered as pathological if acid exposure time (AET) is greater than 6% on pH testing. Number of reflux episodes and baseline impedance are exploratory metrics that may complement AET. Positive symptom reflux association is defined as symptom index (SI) >50% or symptom association probability (SAP) >95%. A positive symptom-reflux association in the absence of pathological AET defines hypersensitivity to reflux.

CONCLUSIONS AND INFERENCES

The consensus group determined that grade C or D esophagitis, peptic stricture, histology proven Barrett's mucosa >1 cm, and esophageal acid exposure greater >6% are sufficient to define pathological GERD. Further testing should be considered when none of these criteria are fulfilled.

MR-FLIP: a new method that combines a functional lumen imaging probe with anatomical information for spatial compliance assessment of the anal sphincter muscles

AIM

Continence results from a complex interplay between anal canal (AC) muscles and sensorimotor feedback mechanisms. The passive ability of the AC to withstand opening pressure - its compliance - has recently been shown to correlate with continence. A functional lumen imaging probe (FLIP) is used to assess AC compliance, although it provides no anatomical information. Therefore, assessment of the compliance specific anatomical structures has not been possible, and the anatomical position of critical functional zones remains unknown. In addition, the FLIP technique assumes a circular orifice cross-section, which has not been shown for the AC. To address these shortcomings, a technique combining FLIP with a medical imaging modality is needed.

METHOD

We implemented a new research method (MR-FLIP) that combines FLIP with MR imaging. Twenty healthy volunteers underwent MR-FLIP and conventional FLIP assessment. MR-FLIP was validated by comparison with FLIP results. Anatomical markers were identified, and the cross-sectional shape of the orifice was investigated.

RESULTS

MR-FLIP provides compliance measurements identical to those obtained by conventional FLIP. Anatomical analysis revealed that the least compliant AC zone was located at the proximal end of the external anal sphincter (EAS). The cross-sectional shape of the AC was found to deviate only slightly from circularity in healthy volunteers.

CONCLUSION

The proposed method is equivalent to classical FLIP. It establishes for the first time direct mapping between local tissue compliance and anatomical structure, which is key to gaining novel insights into (in)continence. In addition, MR-FLIP provides a tool for better understanding conventional FLIP measurements in the AC by quantifying its limitations and assumptions.

The selective metabotropic glutamate receptor 5 antagonist mavoglurant (AFQ056) reduces the incidence of reflux episodes in dogs and patients with moderate to severe gastroesophageal reflux disease

BACKGROUND

Transient lower esophageal sphincter relaxations (TLESRs) induced by gastric distension are modulated by the metabotropic glutamate receptor 5 (mGluR5) that influences the vagal reflex loop. We therefore aimed to examine the effects of the selective mGluR5 antagonist mavoglurant (AFQ056) on the number of TLESRs in dogs and reflux episodes in patients with gastroesophageal reflux disease (GERD).

METHODS

In a dog model, the number of meal-induced TLESRs was determined after intravenous (0.03, 0.1, 0.3, and 1 mg kg^-1 ) and oral (1, 3, and 10 mg kg^-1 ) doses of mavoglurant with reference to vehicle. In a multicenter, randomized, double-blind, placebo-controlled, three-period crossover study, the incidence of meal-induced reflux episodes was assessed by esophageal impedance monitoring after single, oral doses of mavoglurant (50 and 400 mg) or baclofen (40 mg) in 30 patients with moderate to severe GERD.

KEY RESULTS

In dogs, mavoglurant reduced the number of TLESRs after intravenous and oral administration. In patients with GERD, the incidence of postprandial reflux episodes was significantly lower at a dose of 400 mg mavoglurant (-37.5% ; 90% confidence interval [CI]: -57.8, -17.2), whereas there was no significant difference at 50 mg of mavoglurant compared to placebo. A significantly lower incidence of reflux episodes was also noted with the active comparator baclofen (-50.3%; 90% CI: -66.2, -34.3), thereby validating this study.

CONCLUSIONS AND INFERENCES

These data suggest a potential clinical benefit of mGluR5 antagonists such as mavoglurant in patients with GERD, particularly in those with persisting symptoms despite treatment with proton pump inhibitors.

Vigor of peristalsis during multiple rapid swallows is inversely correlated with acid exposure time in patients with NERD

BACKGROUND

Multiple rapid swallowing (MRS) during high-resolution manometry (HRM) is increasingly utilized as provocative test to assess esophageal peristaltic reserve. The aim of this study was to evaluate the correlation between MRS response and impedance and pH (MII-pH) parameters in endoscopy negative heartburn (ENH) patients.

METHODS

We enrolled consecutive ENH patients, who underwent HRM and MII-pH study, with a selected MII-pH profile: abnormal MII-pH (pH+/MII+); normal MII-pH (pH-/MII-). HRM was performed with 10 wet swallows (WS) and one MRS. Mean distal contractile integral (DCI) during WS and MRS were calculated. MII-pH parameters including acid exposure time (AET), reflux events, baseline impedance levels (BI) and the efficacy of chemical clearance evaluated with the postreflux swallow-induced peristaltic wave (PSPW) index were measured.

KEY RESULTS

We analyzed 103 patients: 49 MII+/pH+ (27 male), and 54 MII-/pH- (19 male). Mean age was similar between the two groups. As expected, mean AET and number of refluxes were higher in pH+/MII+ (p < 0.05). HRM was normal in all selected patients. Mean DCI-WS was similar between two groups (p = n.s.). Mean DCI-MRS- was higher in MII-/pH- vs MII+/pH+ (p < 0.05). The increase in DCI-MRS was inversely correlated with AET (-0.699; p < 0.001) and directly correlated with BI values (0.631; p < 0.001) and PSPW index (0.626; p < 0.001).

CONCLUSIONS & INFERENCES

Following MRS, patients with abnormal impedance-pH test showed suboptimal contraction response as compared with those with normal impedance-pH test. Moreover, MRS response was inversely correlated with AET and directly correlated with BI values and PSPW index.

Inter-observer agreement for diagnostic classification of esophageal motility disorders defined in high-resolution manometry

High-resolution esophageal manometry (HRM) is a recent development used in the evaluation of esophageal function. Our aim was to assess the inter-observer agreement for diagnosis of esophageal motility disorders using this technology. Practitioners registered on the HRM Working Group website were invited to review and classify (i) 147 individual water swallows and (ii) 40 diagnostic studies comprising 10 swallows using a drop-down menu that followed the Chicago Classification system. Data were presented using a standardized format with pressure contours without a summary of HRM metrics. The sequence of swallows was fixed for each user but randomized between users to avoid sequence bias. Participants were blinded to other entries. (i) Individual swallows were assessed by 18 practitioners (13 institutions). Consensus agreement (≤ 2/18 dissenters) was present for most cases of normal peristalsis and achalasia but not for cases of peristaltic dysmotility. (ii) Diagnostic studies were assessed by 36 practitioners (28 institutions). Overall inter-observer agreement was 'moderate' (kappa 0.51) being 'substantial' (kappa > 0.7) for achalasia type I/II and no lower than 'fair-moderate' (kappa >0.34) for any diagnosis. Overall agreement was somewhat higher among those that had performed >400 studies (n = 9; kappa 0.55) and 'substantial' among experts involved in development of the Chicago Classification system (n = 4; kappa 0.66). This prospective, randomized, and blinded study reports an acceptable level of inter-observer agreement for HRM diagnoses across the full spectrum of esophageal motility disorders for a large group of clinicians working in a range of medical institutions. Suboptimal agreement for diagnosis of peristaltic motility disorders highlights contribution of objective HRM metrics.

MR imaging in Crohn's disease: correlation of MR motility measurement with histopathology in the terminal ileum

BACKGROUND

The objective of the study was to correlate MR-detectable motility alterations of the terminal ileum with biopsy-documented active and chronic changes in Crohn's disease.

METHODS

This IRB approved retrospective analysis of 43 patients included magnetic resonance enterography (MRE) and terminal ileum biopsies (<2 weeks apart). Motility was measured at the terminal ileum using coronal 2D trueFISP pulse sequences (1.5T MRI,TR 83.8,TE1.89) and dedicated motility assessment software. Motility grading (hypermotility, normal, hypomotility, complete arrest) was agreed by two experienced readers. Motility was compared and correlated with histopathology using two-tailed Kruskal-Wallis test and paired Spearman Rank-Order Correlation tests.

KEY RESULTS

Motility abnormalities were present in 27/43 patients: nine hypomotility and 18 complete arrest. Active disease was diagnosed on 15 biopsies: eight moderate and seven severe inflammatory activity. Chronic changes were diagnosed on 17 biopsies: 13 moderate and four severe cases. In four patients with normal motility alterations on histopathology were diagnosed. Histopathology correlated with presence (P = 0.0056 for hypomotility and P = 0.0119 for complete arrest) and grade (P < 0.0001; P = 0.0004) of motility alterations. A significant difference in the motility was observed in patients with active or chronic CD compared with patients without disease (P < 0.001; P = 0.0024).

CONCLUSIONS & INFERENCES

MR-detectable motility changes of the terminal ileum correlate with histopathological findings both in active and chronic CD. Motility changes may indicate the presence pathology, but do not allow differentiation of active and chronic disease.

Differentiation between active and chronic Crohn's disease using MRI small-bowel motility examinations - initial experience

AIM

To evaluate the influence of locally active Crohn's disease on systemic small-bowel motility in patients with chronic Crohn's disease compared to healthy individuals.

MATERIAL AND METHODS

Fifteen healthy individuals (11 men, four women; mean age 37 years) and 20 patients with histopathologically proven active (n = 15; 10 women, 5 men; mean age 45 years) or chronic (n = 5; four women, one man; mean age 48 years) Crohn's disease were included in this institutional review board-approved, retrospective study. Magnetic resonance imaging (MRI; 1.5 T) was performed after standardized preparation. Two-dimensional (2D) cine sequences for motility acquisition were performed in apnoea (27 s). Motility assessment was performed using dedicated software in three randomly chosen areas of the small-bowel outside known Crohn's disease-affected hotspots. The main quantitative characteristics (frequency, amplitude, occlusion rate) were compared using Student's t-test and one-way analysis of variance (ANOVA).

RESULTS

Three randomly chosen segments were analysed in each participant. Patients with active Crohn's disease had significantly (p < 0.05) reduced contraction frequencies (active Crohn's disease: 2.86/min; chronic: 4.14/min; healthy: 4.53/min) and luminal occlusion rates (active: 0.43; chronic: 0.70; healthy: 0.73) compared to healthy individuals and patients with chronic Crohn's disease. Contraction amplitudes were significantly reduced during active Crohn's disease (6.71 mm) compared to healthy participants (10.14 mm), but this only reached borderline significance in comparison to chronic Crohn's disease (8.87 mm). Mean bowel lumen diameter was significantly (p = 0.04) higher in patients with active Crohn's disease (16.91 mm) compared to healthy participants (14.79 mm) but not in comparison to patients with chronic Crohn's disease (13.68).

CONCLUSION

The findings of the present study suggest that local inflammatory activity of small-bowel segments in patients with active Crohn's disease alters small-bowel motility in distant, non-affected segments. The motility patterns revealed reduced contraction-wave frequencies, amplitudes, and decreased luminal occlusion rates. Thus evaluation of these characteristics potentially helps to differentiate between chronic and active Crohn's disease.

Esophageal hypertensive peristaltic disorders

BACKGROUND

Esophageal motility abnormalities include a series of manometric findings that differ to a significant degree from findings in normal, asymptomatic volunteers.

METHODS

Current review summarizes conventional and high-resolution esophageal manometry criteria used to define and characterize esophageal hypertensive motility abnormalities.

KEY RESULTS

In the conventional esophageal manometry classification scheme hypertensive esophageal motility abnormalities include nutcracker esophagus (average distal contraction amplitude >180 mmHg), hypertensive lower esophageal sphincter (average resting LES pressure >45 mmHg) and poorly relaxing lower esophageal sphincter (average LES residual pressure >8 mmHg). The new, high resolution esophageal manometry scheme includes in the group of hypertensive peristaltic disorders hypertensive peristalsis ("nutcracker esophagus": mean DCI >5000 mmHg*sec*cm) and hypercontractile esophagus ("jackhammer esophagus": at least one contraction with DCI > 8,000 mmHg*sec*cm) and defines a separate group for disorders with impaired esophageal-gastric junction relaxation (mean integrated residual (LES) pressure >15 mmHg).

CONCLUSIONS & INFERENCES

Hypertensive motility disorders represent a heterogeneous condition subdivided into hypercontractile esophagus and hypertensive peristalsis. Further studies are required to determine the clinical relevance of this new classification.

Oesophageal motility and bolus transit abnormalities increase in parallel with the severity of gastro-oesophageal reflux disease

BACKGROUND

Limited data are available regarding the frequency of oesophageal motility and bolus transit abnormalities in subgroups of patients with gastro-oesophageal reflux disease (GERD).

AIM

To assess oesophageal motility and bolus transit in endoscopically defined GERD subgroups.

METHODS

Patients (N=755) with typical reflux symptoms underwent upper endoscopy, conventional or impedance oesophageal manometry and/or impedance-pH testing. They were divided into: erosive oesophagitis (EO; N=340), Barrett Oesophagus (BO; N=106), non-erosive reflux disease (NERD; endoscopy-, abnormal pH and/or SAP/SI+; N=239) and functional heartburn (FH; endoscopy-, normal pH and SAP/SI-; N=70). Manometric patterns and bolus transit were defined according to previously published criteria.

RESULTS

Increasing GERD severity was associated with decreased lower oesophageal sphincter resting pressure (P< 0.05) and distal oesophageal amplitude (P<0.01), higher prevalence of hiatal hernia (P<0.01) and increased prevalence of ineffective oesophageal motility (P<0.01). Patients with EO and BO had a significantly lower percentage of complete bolus transit compared with NERD and FH (P<0.01). Overall, abnormal bolus transit (ABT) for liquid swallows was found in 12% of FH, 20% of NERD, 54% of EO and 56% of BO (P<0.01). Combined impedance-manometry showed abnormal oesophageal function in 4% of FH, 4% of NERD, 22% of EO and 21% of BO patients with normal oesophageal manometry.

CONCLUSIONS

Oesophageal motility abnormalities increase in parallel with the severity of GERD from NERD to EO and BO. Bolus transit abnormalities in severe reflux disease underscore the importance of impaired oesophageal function in the development of mucosal injury.

Randomised clinical trial: effects of monotherapy with ADX10059, a mGluR5 inhibitor, on symptoms and reflux events in patients with gastro-oesophageal reflux disease

BACKGROUND

ADX10059, a metabotropic glutamate receptor 5 (mGluR5) negative allosteric modulator, has been shown to reduce gastro-oesophageal reflux events and oesophageal acid exposure in patients with gastro-oesophageal reflux disease (GERD) and healthy subjects.

AIM

  To evaluate the effects of ADX10059 monotherapy for 2 weeks on symptom control in patients with GERD.

METHODS

This was a double-blind, placebo-controlled, multi-centre trial in GERD patients who were responders to proton pump inhibitors (PPIs). Following PPIs withdrawal, a 2-week baseline washout period was followed by 2-week treatment with either ADX10059 120 mg or placebo b.d. The primary clinical efficacy endpoint was the number of GERD symptom-free days in treatment week 2 compared with the last 7 days of baseline. The effect on reflux events using 24-h impedance-pH monitoring was also determined in a subset of 24 patients.

RESULTS

The full analysis set comprised 103 patients ADX10059 (N= 50), Placebo (N=53). In treatment week 2, ADX10059 significantly increased GERD symptom-free days (P=0.045) and heartburn-free days (P=0.037), reduced antacid use (P=0.017), improved total symptom score (P=0.048) including subscale heartburn/regurgitation (P=0.007) and sleep disturbance because of GERD (P= 0.022). ADX10059 significantly reduced total (P=0.034) and acidic reflux events (P=0.003). ADX10059 was well tolerated. Most common adverse events for ADX10059 were mild to moderate dizziness 16% and vertigo 12% (placebo 4% and 2%).

CONCLUSIONS

Inhibition of mGluR5 with ADX10059 monotherapy reduces reflux events and improves symptoms in GERD patients. This mechanism has promise for the management of GERD.

MR defecography in patients with dyssynergic defecation: spectrum of imaging findings and diagnostic value

OBJECTIVES

We describe the spectrum of findings and the diagnostic value of MR defecography in patients referred with suspicion of dyssynergic defecation.

METHODS

48 patients (34 females, 14 males; mean age 48 years) with constipation and clinically suspected dyssynergic defecation underwent MR defecography. Patients were divided into patients with dyssynergic defecation (n = 18) and constipated patients without dyssynergic defecation (control group, n = 30). MRIs were analysed for evacuation ability, time to initiate evacuation, time of evacuation, changes in the anorectal angle (ARA-change), presence of paradoxical sphincter contraction and presence of additional pelvic floor abnormalities. Sensitivity, specificity, positive and negative predictive values and accuracy for the diagnosis of dyssynergic defecation were calculated.

RESULTS

The most frequent finding was impaired evacuation, which was seen in 100% of patients with dyssynergic defecation and in 83% of the control group, yielding a sensitivity for MR defecography for the diagnosis of dyssynergic defecation of 100% (95% confidence interval (CI) 97-100%), but a specificity of only 23% (95% CI 7-40%). A lower sensitivity (50%; 95% CI 24-76%) and a high specificity (97%; 95% CI 89-100%) were seen with abnormal ARA-change. The sensitivity of paradoxical sphincter contraction was relatively high (83%; 95% CI 63-100%). A combined analysis of abnormal ARA-change and paradoxical sphincter contraction allowed for the detection of 94% (95% CI 81-100%) of the patients with dyssynergic defecation.

CONCLUSION

MR defecography detects functional and structural abnormal findings in patients with clinically suspected dyssynergic defecation. Impaired evacuation is seen in patients with functional constipation owing to other pelvic floor abnormalities than dyssynergic defecation.

Characteristics of gastro-esophageal reflux episodes in Barrett's esophagus, erosive esophagitis and healthy volunteers

BACKGROUND

Gastro-esophageal reflux is considered a major culprit in the pathogenesis of Barrett's esophagus (BE). Still, there is controversy on the role of weakly acidic and weakly alkaline reflux in BE. To compare characteristics of reflux episodes patients with BE, erosive esophagitis (EE), and healthy volunteers (HV).

METHODS

One hundred consecutive patients with BE (75 short-segment BE, 25 long-segment BE), 50 with EE and 48 HV underwent multichannel intraluminal impedance-pH off-therapy. We quantified esophageal acid exposure, characteristics, and proximal extension of reflux episodes.

KEY RESULTS

Total and acid reflux episodes gradually increased from HV [28 (17.5-43) and 18 (8-31)] to EE [73.5 (54-96) and 52 (39-68)], short-segment BE (SSBE) [83 (73.2-131) and 65 (43.3-95)] and long-segment BE (LSBE) [105 (102-187) and 77 (75-107)]. Weakly acidic reflux episodes were significantly higher (P < 0.05) in LSBE [36 (27.5-50.5)] and SSBE [34 (18.5-41)] compared to EE [21.5 (15-37)] and HV [19 (14-25)]. No differences in terms of proportion of acid, weakly acidic and weakly alkaline reflux were found [HV (49%-49%-2%) vs EE (68%-32%-1%) vs SSBE (65%-34%-1%) vs LSBE (69%-30%-1%); P = ns]. In LSBE, a higher percentage of reflux episodes (P < 0.05) reached the proximal esophagus (59%) compared with SSBE (43%).

CONCLUSIONS & INFERENCES

 Barrett esophagus patients have more severe reflux as shown by the number of acid and weakly acidic reflux episodes, re-reflux episodes and proximal migration. Given that PPI change only the pH of the refluxate, the role of weakly acidic reflux in Barrett's patients on acid suppressive therapy warrants further investigation.

Air suctioning during colon biopsy forceps removal reduces bacterial air contamination in the endoscopy suite

BACKGROUND AND STUDY AIMS

Bacterial contamination of endoscopy suites is of concern; however studies evaluating bacterial aerosols are lacking. We aimed to determine the effectiveness of air suctioning during removal of biopsy forceps in reducing bacterial air contamination.

PATIENTS AND METHODS

This was a prospective single-blinded trial involving 50 patients who were undergoing elective nontherapeutic colonoscopy. During colonoscopy, endoscopists removed the biopsy forceps first without and then with suctioning following contact with the sigmoid mucosa. A total of 50 L of air was collected continuously for 30 seconds at 30-cm distance from the biopsy channel valve of the colonoscope, with time starting at forceps removal. Airborne bacteria were collected by an impactor air sampler (MAS-100). Standard Petri dishes with CNA blood agar were used to culture Gram-positive bacteria. Main outcome measure was the bacterial load in endoscopy room air.

RESULTS

At the beginning and end of the daily colonoscopy program, the median (and interquartile [IQR] range) bioaerosol burden was 4 colony forming units (CFU)/m (3) (IQR 3 - 6) and 16 CFU/m (3) (IQR 13 - 18), respectively. Air suctioning during removal of the biopsy forceps reduced the bioaerosol burden from a median of 14 CFU/m (3) (IQR 11 - 29) to a median of 7 CFU/m (3) (IQR 4 - 16) ( P = 0.0001). Predominantly enterococci were identified on the agar plates.

CONCLUSION

The bacterial aerosol burden during handling of biopsy forceps can be reduced by applying air suction while removing the forceps. This simple method may reduce transmission of infectious agents during gastrointestinal endoscopies.

Functional heartburn has more in common with functional dyspepsia than with non-erosive reflux disease

INTRODUCTION

Functional dyspepsia and non-erosive reflux disease (NERD) are prevalent gastrointestinal conditions with accumulating evidence regarding an overlap between the two. Still, patients with NERD represent a very heterogeneous group and limited data on dyspeptic symptoms in various subgroups of NERD are available.

AIM

To evaluate the prevalence of dyspeptic symptoms in patients with NERD subclassified by using 24 h impedance-pH monitoring (MII-pH).

METHODS

Patients with typical reflux symptoms and normal endoscopy underwent impedance-pH monitoring off proton pump inhibitor treatment. Oesophageal acid exposure time (AET), type of acid and non-acid reflux episodes, and symptom association probability (SAP) were calculated. A validated dyspepsia questionnaire was used to quantify dyspeptic symptoms prior to reflux monitoring.

RESULTS

Of 200 patients with NERD (105 female; median age, 48 years), 81 (41%) had an abnormal oesophageal AET (NERD pH-POS), 65 (32%) had normal oesophageal AET and positive SAP for acid and/or non-acid reflux (hypersensitive oesophagus), and 54 (27%) had normal oesophageal AET and negative SAP (functional heartburn). Patients with functional heartburn had more frequent (p<0.01) postprandial fullness, bloating, early satiety and nausea compared to patients with NERD pH-POS and hypersensitive oesophagus.

CONCLUSION

The increased prevalence of dyspeptic symptoms in patients with functional heartburn reinforces the concept that functional gastrointestinal disorders extend beyond the boundaries suggested by the anatomical location of symptoms. This should be regarded as a further argument to test patients with symptoms of gastro-oesophageal reflux disease in order to separate patients with functional heartburn from patients with NERD in whom symptoms are associated with gastro-oesophageal reflux.

Symptoms with acid and nonacid reflux may be produced by different mechanisms

Twenty-four-hour multichannel intraluminal impedance and pH (MII-pH) esophageal monitoring detects both acid and nonacid gastroesophageal reflux episodes. The MII-pH catheter contains six impedance segments placed 3, 5, 7, 9, 15, and 17 cm above the lower esophageal sphincter (LES). A pH electrode at 5 cm above the LES identifies the type of reflux, i.e. acid or nonacid. Patients with acid and nonacid reflux exhibit typical and atypical symptoms often within 5 min following a reflux episode. The aim of this study is to compare the timing of symptoms after reflux episodes in patients with acid and nonacid reflux. Methods include a review of 70 MII-pH tracings (42 females, mean age 40, range 18-85 years) either on (50 points) or off (20 points) acid suppression therapy. Typical (heartburn, regurgitation) and atypical (cough) symptoms with acid or nonacid reflux episodes detected by impedance were analyzed. Symptoms were considered positive with acid reflux if there was a pH drop to <4, plus an MII detected a reflux episode and with nonacid reflux if pH remained >4 and MII detected a reflux episode. The timing of the symptom after each reflux episode was recorded. Symptom perception occurred significantly sooner after acid versus nonacid reflux (P < 0.05). Acid reflux episodes are more likely to be perceived in the first 2 min following the reflux episode. Patients with acid reflux are likely to perceive symptoms earlier, and symptoms with acid and nonacid reflux may be produced by different mechanisms.

Correlation between symptoms developed after the oral ingestion of 50 g lactose and results of hydrogen breath testing for lactose intolerance

BACKGROUND

Lactase deficiency is a common condition responsible for various abdominal symptoms. Lactose hydrogen breath test is currently the gold standard in diagnosing lactose intolerance.

AIM

To assess sensitivity and specificity of symptoms developed after oral lactose challenge.

METHODS

Intensity of nausea, abdominal pain, borborygmi, bloating and diarrhoea was recorded every 15 min up to 3 h after ingestion of 50 g lactose in patients with positive (i.e. breath H2-concentration > or =20 p.p.m. above baseline) and negative lactose hydrogen breath test.

RESULTS

Between July 1999 and December 2005, 1127 patients (72% females) underwent lactose hydrogen breath test. A positive result was found in 376 (33%). Sensitivity of individual symptoms ranged from 39% (diarrhoea) to 70% (bloating) while specificity ranged from 69% (bloating) to 90% (diarrhoea). A positive lactose hydrogen breath test was found in 21% of patients with one symptom, 40% of patients with two symptoms, 44% of patients with three symptoms, 67% of patients with four symptoms and 82% of patients with five symptoms. Symptom intensity was significantly higher for each symptom in the positive group.

CONCLUSION

Evaluating symptoms developed after ingestion of 50 g lactose can be used as a simple screening test to select patients who need to be referred for lactose intolerance testing.

Combined multichannel intraluminal impedance and manometry testing

Oesophageal manometry has been considered the "gold standard" test for the evaluation of oesophageal motility. Oesophageal manometry allows physicians to assess peristalsis by using informations about the shape, amplitude and duration of the oesophageal contraction, but it does not offer direct information about bolus transit through the oesophagus. Recent studies demonstrate that combined impedance-manometry provides important additional information about oesophageal motility as compared to conventional manometry such as: (1) monitoring of bolus transport patterns without the use of radiation, (2) calculation of bolus transit parameters, (3) evaluation of bolus clearance and (4) investigation of the relationships between bolus transit and LES relaxation. These changes could potentially improve diagnostic accuracy of oesophageal motility testing, advancing both clinical and basic research. This review focuses on current aspects of the novel technology of combined impedance-manometry for oesophageal motility testing.

Multichannel intraluminal impedance and esophageal manometry data for unrestricted swallowing: establishing normal values

Standard esophageal manometric testing evaluates swallowing in the supine position using small boluses, with a recovery period imposed between swallows. Manometric tests of more physiologic unrestricted swallowing have had limited practical application due to highly variable results. The purpose of this study is to apply multichannel intraluminal impedance and manometry (MII-EM) to test esophageal function during unrestricted upright meal consumption, and to assess results in a normal healthy population. Ten healthy volunteers with normal esophageal impedance and manometry by published criteria underwent MII-EM testing using a combined 5-channel catheter. After transnasal placement of the catheter, each subject sat upright and consumed a meal that consisted of two pieces of toasted bread and two ounces of Gatorade. There were no restrictions placed on chewing, swallowing, or eating time. All data assessed by the MII-EM meal test were normally distributed. Impedance results with limited variability included the meal duration, number of swallows, postprandial emptying time and the percent of bolus presence times at 15, 10, and 5 cm above the lower esophageal sphincter. Manometric results with limited variability included the number of peristaltic sequences, mean time between these sequences and their distal esophageal amplitudes. MII-EM can be used to collect data with minimal variability in healthy subjects during unrestricted upright meal consumption. This technique may be used to identify abnormal motility patterns during physiologic swallowing.

An audit of technical pitfalls of gastric barostat testing in dyspepsia

Sensorimotor dysfunction of the proximal stomach is considered an important mechanism for symptom generation in functional dyspepsia and related conditions. Barostat studies are used to assess gastric sensitivity to distention, compliance and meal-induced accommodation. The aim of the present study was to assess tolerance and pitfalls of gastric barostat studies at a tertiary care centre. We performed a retrospective review of patient barostat studies between 01/2000 and 12/2004 at Leuven University Hospital. We evaluated compliance with the procedure, suggestions of air leaks, unusual sensory reporting, baseline intra-balloon volumes, gastric accommodation and phasic contractions after a meal. About 98.1% of 414 scheduled gastric barostat studies were well tolerated and the majority (94.1%) were technically adequate. Interpretation was hampered in 18 (4.4%) studies because of low intra-balloon volumes and in six (1.5%) studies because of suspected air leaks. Negative accommodation was found in 69% of studies with low volumes and in 9.8% of 382 studies with adequate volumes (27% patients with previous antireflux surgery). About 94% of gastric barostat studies in patients with upper gastrointestinal symptoms are well tolerated and technically adequate. Major artefacts are due to air leak or inappropriately low volumes.

Combined multichannel intraluminal impedance-pH monitoring to select patients with persistent gastro-oesophageal reflux for laparoscopic Nissen fundoplication

BACKGROUND

Combined multichannel intraluminal impedance-pH (MII-pH) monitoring detects gastro-oesophageal reflux and identifies acid and non-acid reflux events. It can be used in patients with persistent symptoms on proton-pump inhibitor (PPI) therapy. The aim of this study was to assess laparoscopic Nissen fundoplication as a treatment for patients with persistent symptoms associated with reflux despite acid suppression documented by MII-pH monitoring.

METHOD

A prospectively maintained database identified patients with persistent symptoms of gastro-oesophageal reflux disease despite PPI therapy who had undergone MII-pH monitoring and this was cross-referenced with patients who had undergone fundoplication at this institution. Follow-up after fundoplication was by periodic telephone interview and review of clinical records.

RESULTS

Of 200 evaluated patients, 19 (14 female; mean age 40 (range 0.7-78) years) underwent laparoscopic Nissen fundoplication. Before surgery, 18 of 19 patients had a positive symptom index (at least half of symptoms associated with reflux) and one, a negative symptom index. After a mean follow-up of 14 (range 7-25) months, 16 of 17 (94 per cent) patients with a positive symptom index were asymptomatic or markedly improved (one patient was lost to follow-up). Persistent symptoms occurred in the patient with a negative symptom index, and one patient had recurrent symptoms after 9 months.

CONCLUSION

Patients with a positive symptom index resistant to PPIs with non-acid or acid reflux demonstrated by MII-pH monitoring can be treated successfully by laparoscopic Nissen fundoplication.

Contribution of sensitivity, volume and tone to visceral perception in the upper gastrointestinal tract in man: emphasis on testing

Upper gastrointestinal (GI) symptoms occur frequently in the general population, making them among the most common indications responsible for patients consulting the healthcare system. Consequently, understanding and characterization of the upper GI symptoms is important for the diagnosis and assessment of organ dysfunction. In practice, assessment of clinical symptoms is difficult and it is still to a large extent unclear how sensitivity, volume and tone contribute to visceral perception in the upper GI tract. The goal of advanced research in upper GI symptoms is to obtain a better understanding of the mechanisms involved in transduction, transmission, and perception under normal and pathophysiological conditions. An important step towards this goal is understanding the information provided by and the inherent limitations of the currently available measuring techniques. This article focuses on the sensory testing of the oesophagus, and methods and concepts used to assess the relation between gastric volumes or tone and upper GI symptoms. It also summarizes the contributions of these techniques towards identifying the components responsible for the generation of upper GI symptoms.

Acid and non-acid reflux in patients with persistent symptoms despite acid suppressive therapy: a multicentre study using combined ambulatory impedance-pH monitoring

BACKGROUND AND AIMS

Empiric proton pump inhibitor (PPI) trials have become increasingly popular leading to gastroenterologists frequently evaluating gastro-oesophageal reflux disease (GORD) patients only after they have "failed" PPI therapy. Combined multichannel intraluminal impedance and pH (MII-pH) monitoring has the ability to detect gastro-oesophageal reflux (GOR) episodes independent of their pH and evaluate the relationship between symptoms and all types of GOR. Using this technique, we aimed to characterise the frequency of acid and non-acid reflux (NAR) and their relationship to typical and atypical GOR symptoms in patients on PPI therapy.

METHODS

Patients with persistent GORD symptoms referred to three centres underwent 24 hour combined MII-pH monitoring while taking PPIs at least twice daily. Reflux episodes were detected by impedance channels located 3, 5, 7, 9, 15, and 17 cm above the lower oesophageal sphincter (LOS) and classified into acid or non-acid based on pH data from 5 cm above the LOS. A positive symptom index (SI) was declared if at least half of each specific symptom events were preceded by reflux episodes within five minutes.

RESULTS

A total of 168 patients (103 (61%) females and 65 (39%) males; mean age 53 (range 18-85) years) underwent combined MII-pH monitoring while taking PPIs at least twice daily. One hundred and forty four (86%) patients recorded symptoms during the study day and 24 (15%) patients had no symptoms during testing. Sixty nine (48%) symptomatic patients had a positive SI for at least one symptom (16 (11%) with acid reflux and 53 (37%) with NAR) and 75 (52%) had a negative SI. A total of 171 (57%) typical GORD symptoms were recorded, 19 (11%) had a positive SI for acid reflux, 52 (31%) for NAR, and 100 (58%) had a negative SI. One hundred and thirty one (43%) atypical symptoms were recorded, four (3%) had a positive SI for acid reflux, 25 (19%) had a positive SI for NAR, and 102 (78%) had a negative SI.

CONCLUSION

Combined MII-pH identifies the relation of reflux of all types to persistent symptoms and the importance of NAR in patients taking PPIs.

Review article: complete gastro-oesophageal reflux monitoring - combined pH and impedance

Gastroesophagel reflux disease (GERD) is a common condition encountered in clinical practice. Over the years there has been a continuous interaction between the understanding of the disease, the diagnostic tools and treatments of GERD. The use of proton pump inhibitor (PPI) trials by primary care physicians as diagnostic tool in patients with symptoms suspected to be due to GERD has led to a shift in the type of patients referred to specialists. Currently, gastrointestinal specialists are frequently asked to evaluate patients with persistent reflux symptoms despite acid suppressive therapy. In these patients symptoms can be associated with reflux (both acid and non-acid) or not associated with reflux. While conventional pH monitoring can quantify esophageal acid exposure and evaluate the association between symptoms and acid reflux, it cannot reliably detect reflux episodes with a pH > 4 (i.e. non-acid reflux). Detecting reflux episodes by changes in intraluminal resistance to alternating current (i.e. impedance), combined multichannel intraluminal impedance and pH (MII-pH) monitoring offers the opportunity to detect both acid and non-acid reflux episodes and to evaluate the relationship between symptoms and reflux. We believe that MII-pH monitoring has become the new ''gold standard'' for clarifying the mechanisms of persistent symptom on PPI therapy.

Effects of a 5-HT(4) receptor agonist on oesophageal function and gastro-oesophageal reflux: studies using combined impedance-manometry and combined impedance-pH

BACKGROUND

5-HT(4) receptor agonists are used as promotility agents of the stomach, small and large intestine. There is limited information on the influence of 5-HT(4) receptor agonists on oesophageal function and gastro-oesophageal reflux.

AIM

To evaluate the effects of tegaserod, a 5-HT(4) agonist on oesophageal function using impedance-manometry and postprandial reflux using impedance-pH monitoring.

METHODS

Twenty healthy volunteers were enrolled in a double-blind randomized three-period crossover placebo-controlled study. Impedance-manometry and impedance-pH monitoring after a refluxogenic meal were performed at baseline and after 2 days of dosing with tegaserod 6 mg b.d. or placebo. Multichannel intraluminal impedance-EM recorded pressure and bolus transit data during standardized swallows. Multichannel intraluminal impedance-pH monitoring recorded the number of 2-h postprandial acid and non-acid reflux episodes.

RESULTS

We found no significant difference in distal oesophageal amplitude when subjects received placebo (median 94.5; range: 53-243 mmHg) or tegaserod (93.6; 43-216 mmHg). Bolus transit time was similar during dosing with placebo (7.1; 5.3-9.4 s) and tegaserod (7.2; 5.9-11.1 s). We observed similar numbers of acid and non-acid reflux episodes during dosing with placebo (5; 0-15 and 3; 0-18, respectively) and tegaserod (2; 0-11 and 4; 0-19, respectively).

CONCLUSION

Tegaserod, a 5-HT(4) receptor agonist does not change oesophageal motility and gastro-oesophageal reflux parameters in healthy volunteers.

Review article: oesophageal spasm - diagnosis and management

Oesophageal spasm is a common empiric diagnosis clinically applied to patients with unexplained chest pain. In contrast it is an uncommon manometric abnormality found in patients presenting with chest pain and/or dysphagia and diagnosed by >or=20% simultaneous oesophageal contractions during standardized motility testing. Using Medline we searched for diagnostic criteria and treatment options for oesophageal spasm. While the aetiology of this condition is unclear, studies suggest the culprit being a defect in the nitric oxide pathway. Well-known radiographic patterns have low sensitivities and specificities to identify intermittent simultaneous contractions. Recognizing that simultaneous contractions may result from gastro-oesophageal reflux this diagnosis should be investigated or treated first. Studies have documented improvements with proton-pump inhibitors, nitrates, calcium-channel blockers and tricyclic antidepressants or serotonin reuptake inhibitors. Small case series reported benefits after botulinium toxin injections, dilatations and myotomies. Uncertainties persist regarding the optimal management of oesophageal spasm and recommendations are based on controlled studies with small numbers of patients or on case series. Acid suppression, muscle relaxants and visceral analgetics should be tried first. Botulinium toxin injections should be reserved for patients who do not respond. Pneumatic dilatations or myotomies represent rather heroic approaches for non-responding patients.

Histamine-2 receptor antagonists at night improve gastroesophageal reflux disease symptoms for patients on proton pump inhibitor therapy

While night-time symptoms of gastroesophageal reflux disease (GERD) are common, considerable controversy exists regarding the use of histamine-2 receptor antagonists (H2Ras) for night-time reflux control. Some studies have suggested possible tolerance to H2RA while others have suggested that long-term efficacy of gastric acid control can be maintained with night-time H2RA use. The aim of this study was to identify if GERD patients have sustained symptom improvement with long-term use of night-time H2RA. Records of 56 consecutive GERD patients on twice daily proton pump inhibitor (PPI) and night-time H2RA therapy were reviewed. During a phone interview patients were asked a 5-item questionnaire, which included overall assessment of symptoms, night-time symptoms, sleep disturbance, duration and frequency of therapy. Of the 56 patients, 39 (31 women, mean age 56) completed the questionnaire (15 were not reached and 2 did not recall enough information). All respondents had taken night-time H2RA for at least 1 month (28/39 patients with > 6 months duration) with 33/39 patients taking H2RAs every night. The addition of H2RA led to an improvement in overall symptoms in 28/39 (72%) patients, improvement in night-time reflux symptoms in 25/34 (74%) patients and improvement of GERD-associated sleep disturbance in 18/27 (67%) patients. Five (13%) patients had stopped the H2RA on their own, stating that its efficacy waned after 1 month. Our results suggest that the majority of patients report persistent improvement in GERD symptoms from night-time H2RA use and that possible clinically important tolerance to H2RAs occurs in a small number of patients. Further prospective, placebo-controlled studies may help confirm that there is a role for night-time H2RAs in GERD symptom control.

Identification of hiatal hernia by esophageal manometry: is it reliable?

Hiatal hernias are frequently diagnosed during upper endoscopy or barium radiography. They can also be identified based on the typical 'double high pressure zone' or 'double hump' during stationary manometric pull-through. This paper aims to compare manometric and endoscopic identification of hiatal hernias. We retrospectively reviewed records of patients who had an esophageal manometry performed in our laboratory between July 2002 and July 2003. We identified 153 patients (104 females, mean age 56 years) who had both an esophageal manometry and upper endoscopy. The manometric studies were reviewed looking for the characteristic double high-pressure zone characteristic of hiatal hernia. The endoscopic reports were reviewed for the independent identification of an hiatal hernia. Information on race, gender, presence of hiatal hernias, esophagitis, and symptoms during esophagogastroduodenoscopy (EGD) exams was recorded from the reports of patients who had both EGD and manometric studies at our institution. Of the 153 patients with both endoscopy and manometry, 11 (7%) had an hiatal hernia identified by manometry compared to 51 (33%) by endoscopy. Ten (91%) of the manometrically identified hiatal hernias were also seen on endoscopy. Compared to endoscopy (gold standard), esophageal manometry had a sensitivity of 20% and a specificity of 99% for detecting hiatal hernias. Manometric identification of an hiatal hernia is an infrequent finding with low sensitivity but high specificity compared to endoscopy.

Fundoplication eliminates chronic cough due to non-acid reflux identified by impedance pH monitoring

The symptoms of extra-oesophageal gastro-oesophageal reflux disease (GORD) (such as chronic cough and hoarseness) are traditionally more difficult to treat than typical GORD symptoms (heartburn and regurgitation). Patients with extra-oesophageal manifestations may require longer and higher doses of acid suppressive therapy. In patients not responding to acid suppressive therapy the physician faces a dilemma as to whether the symptoms are due to ongoing acid reflux, non-acid reflux, or not associated with reflux. We report the case of a 45 year old woman with a history of a chronic cough referred for fundoplication after documenting her symptoms were associated with non-acid reflux using multichannel intraluminal impedance and pH (MII-pH).

Disposable balloon-based oesophageal motility catheters: comparison with solid-state transducers

BACKGROUND

Current oesophageal manometry systems use either water-perfused or solid-state pressure transducers. Recently developed single-use disposable catheters use small balloons prefilled with air that transmit the pressure of oesophageal contractions to external transducers.

AIM

To compare data obtained from single-use disposable balloon catheters to data from solid-state systems.

METHODS

Healthy volunteers, patients with ineffective oesophageal motility and nutcracker oesophagus were studied to include a broad range of pressures. A single-use disposable Clinical Innovations (CI) catheter was placed adjacent to a solid-state Konigsberg Instruments (KI) catheter with pressure transducers at 5, 10, 15 and 20 cm above the lower oesophageal sphincter (LOS). Subjects received liquid and viscous swallows at 30-s intervals. Healthy volunteers received additional sets of swallows while having only one catheter in the oesophagus.

RESULTS

When both catheters were present in the oesophagus, no differences were noted between mean pressure measurements in the distal oesophagus and there was good correlation between pressures recorded in response to individual swallows. When present alone in the oesophagus the CI catheter recorded lower mean pressures compared with the KI catheter. Overall there was good agreement in classifying swallows as normal, ineffective and simultaneous.

CONCLUSION

Single-use oesophageal manometry catheters are promising alternatives to solid-state manometry systems in measuring intra-oesophageal pressures.

Review article: the pathophysiology of gastro-oesophageal reflux disease - oesophageal manifestations

The pathogenesis of gastro-oesophageal reflux disease (GERD) is multifactorial, involving transient lower oesophageal sphincter relaxations (TLESRs) as well as other lower oesophageal sphincter (LES) pressure abnormalities. GERD is associated with a decrease in LES pressure, which can be provoked by factors such as foods (fat, chocolate, etc.), alcohol, smoking and medications. These factors have also been shown to increase TLESRs. As a result, reflux of acid, bile, pepsin and pancreatic enzymes occurs, leading to oesophageal mucosal injury, which can potentially progress to oesophageal adenocarcinoma in a minority of patients with Barrett's metaplasia. In addition, duodenogastric contents can also contribute to oesophageal injury. Other factors contributing to the pathophysiology of GERD include hiatal hernia, poor oesophageal clearance, delayed gastric emptying and impaired mucosal defensive factors. Hiatal hernia has a permissive role in the pathogenesis of reflux oesophagitis by promoting LES dysfunction. Delayed gastric emptying, resulting in gastric distension, can significantly increase the rate of TLESRs, contributing to postprandial GER. The mucosal defensive factors have an important role in GERD. When excessive acid causes a breakdown in oesophageal epithelial defenses, epithelial resistance may be reduced. Nocturnal GERD is associated with prolonged acid exposure and proximal extent of acid contact, which elevates the risk for oesophageal damage and GERD-related complications. In sum, GERD is a complex problem caused by many factors that are exacerbated when the patient is in the supine position.

The acidity index: a simple approach to the measurement of gastric acidity

BACKGROUND

The percentage of time intragastric pH < 4 is a major parameter in evaluating the efficiency of acid-suppressive therapies. This parameter is easy to calculate, but does not identify the actual pH level. Recent studies have recommended the use of the integrated intragastric acidity as a more refined method of assessing intragastric acid control.

AIM

To describe a new parameter, the acidity index, based on the logarithmic aspect of pH calculation, which may overcome the limitations of the percentage of time intragastric pH < 4 and the integrated intragastric acidity.

METHODS

The acidity index was calculated by obtaining the sum of 1000 x % time pH < 1, 100 x % time pH < 2 and >or= 1, 10 x % time pH < 3 and >or= 2 and % time pH < 4 and >or= 3. The total percentage of time pH < 4 and the integrated intragastric acidity were calculated based on previous descriptions. The correlations between these parameters were analysed.

RESULTS

The mean +/- s.d. values were 60% +/- 22% for the percentage of time pH < 4, 172 +/- 178 for the acidity index and 1114 +/- 1176 mmol/L.h for the integrated intragastric acidity. Both the integrated intragastric acidity (r = 0.63) and acidity index (r = 0.70) showed only fair correlation with the percentage of time pH < 4. In contrast, there was a strong positive correlation (r = 0.93) between the acidity index and integrated intragastric acidity.

CONCLUSION

The acidity index is easy to calculate, allows a more accurate assessment of the intragastric acidity than does the percentage of time pH < 4, and is comparable with the more complicated integrated gastric acidity in assessing intragastric pH control.

Effect of interval between swallows on oesophageal pressures and bolus movement in normal subjects - Studies with combined multichannel intraluminal impedance and oesophageal manometry

The effect of closely spaced swallows to decrease peristalsis ('deglutitive inhibition') is believed to be due to both central inhibitory impulses and smooth muscle refractoriness. Ten volunteers (three females, age 26-65) were given both four pairs and two series of four swallows at 5-, 10-, 15-s intervals and control swallows at 30-s intervals. Oesophageal function was assessed using combined multichannel intraluminal impedance and oesophageal manometry (MII-OM). Swallows were considered manometrical effective if distal oesophageal pressures >/=30 mmHg. Complete bolus transit was defined as bolus exiting from all three distal impedance segments. During swallowing at 5-s intervals the majority of initial swallows were ineffective with incomplete bolus transit while the last swallow in both series and pairs was manometrically effective with complete bolus transit. During swallowing at 10-15-s intervals the number of manometric ineffective swallows and swallows with incomplete bolus transit progressively increased with the number of swallows. The functional information obtained by MII-OM indicates pooling of liquid in the distal oesophagus that is cleared by the last swallow determined by, previously reported, neural inhibition occurring during swallowing spaced 5 s apart whereas incomplete bolus transit is related to manometrically ineffective swallows resulting from muscle refractoriness occurring during swallowing at 10-15-s intervals.

Effects of position on oesophageal function: studies using combined manometry and multichannel intraluminal impedance

Multichannel intraluminal impedance (MII) allows assessment of intraoesophageal bolus transit. In the supine position, bolus transit is produced almost exclusively by peristaltic contractions; in the upright position, gravity also contributes to bolus transit. MII and peristaltic pressures were measured in four positions (0, 30, 60 and 90 degrees ) using ten swallows (5 cc each) of both water and viscous liquid with body position determined by random choice. Tracings were analysed for total bolus transit time: time interval between bolus entry at 20 cm above and bolus exit at 5 cm above the lower oesophageal sphincter (LOS) and contraction amplitudes at 5 and 10 cm above the LOS. Statistical comparison of mean values of all four body positions was done using anova and Bonnferoni post-test. Ten normal subjects (five females and five males, age 24-45 years) completed the study. At each body position, liquid material transited faster (P < 0.001) than viscous material. Both liquid and viscous materials transited at lower inclinations (0 and 30 degrees ) significantly slower than at higher inclinations (60 and 90 degrees ). There was an almost perfect inverse linear correlation between angle of inclination and bolus transit time for both liquid (r = -0.99) and viscous (r = -1.00) boluses (Spearman correlation r > 0.99 and P < 0.02 for both substances). Contraction amplitudes for liquid vs viscous material were not significantly different at a given degree of inclination. Mean distal oesophageal amplitude declined with increasing inclination. Combined MII-OM identifies and quantifies the effects of gravity on the dichotomy between specific pressures measured by OM and function assessed as transit measured by MII.

Baclofen decreases acid and non-acid post-prandial gastro-oesophageal reflux measured by combined multichannel intraluminal impedance and pH

BACKGROUND

Omeprazole controls acid but not non-acid reflux. The GABA B agonist baclofen decreases acid reflux through the inhibition of transient lower oesophageal sphincter relaxations (TLESRs) and should similarly decrease non-acid reflux. Using combined multichannel intraluminal impedance and pH (MII/pH), we compared acid and non-acid reflux after placebo and baclofen.

METHODS

Nine healthy volunteers and nine heartburn patients underwent two 2-h studies of combined MII/pH in right lateral decubitus after a refluxogenic meal in random order: on placebo and after baclofen 40 mg p.o. Tracings were analysed for acid and non-acid reflux episodes, re-reflux and symptoms in the heartburn patients.

RESULTS

In normal subjects baclofen significantly reduced the median number of episodes of acid (7 vs. 1, P = 0.02), non-acid (2 vs. 0, P = 0.005), and all reflux combined (10 vs. 2, P = 0.006); re-reflux was not reduced (0 vs. 0, P = N.S.). In heartburn patients, baclofen significantly decreased the median number of episodes of acid (15 vs. 6, P = 0.004), non-acid (4 vs. 2, P = 0.003), re-reflux (2 vs. 0, P = 0.02), and all reflux combined (23 vs. 8, P = 0.004); it also reduced the median number of acid-related (9 vs. 1, P = 0.008) and non-acid-related (1 vs. 0, P = 0.04) symptoms.

CONCLUSIONS

Baclofen reduces post-prandial acid and non-acid reflux and their associated symptoms. GABA B agonists may have a role in treating GERD.

Dose-dependent control of intragastric pH by pantoprazole, 10, 20 or 40 mg, in healthy volunteers

BACKGROUND

Proton pump inhibitors have emerged as the most effective class of drugs for the treatment of gastro-oesophageal reflux. Pantoprazole is a proton pump inhibitor that has demonstrated high clinical efficacy.

AIM

To evaluate the effect of once-daily doses of pantoprazole, 10, 20 and 40 mg, on gastric acidity in healthy volunteers.

METHODS

Thirty-six subjects received pantoprazole in a three-way crossover design study. Ambulatory 24-h intragastric pH and distal oesophageal pH were monitored at baseline and on the last day of each treatment period. The measured endpoints were the median intragastric and oesophageal pH, the percentage of time the intragastric pH < 4 and oesophageal pH < 4 and the area under the curve for gastric acidity over 24 h. Safety was evaluated by incidence and severity of adverse events.

RESULTS

Pantoprazole demonstrated a linear dose- dependent suppression of gastric acidity over the dose range 10-40 mg. The dose of 40 mg demonstrated a significantly greater response than the lower doses, particularly at night. All pantoprazole doses were well tolerated.

CONCLUSIONS

Pantoprazole demonstrates a dose-related effect in the range 10-40 mg once daily. The once-daily dose of 40 mg provides the highest and most consistent control of gastric pH, especially at night.

Over-the-counter H(2)-receptor antagonists do not compromise intragastric pH control with proton pump inhibitors

BACKGROUND

Proton pump inhibitors effectively suppress intragastric acid. Nocturnal acid breakthrough occurs on any dosing regimen of oral proton pump inhibitors. Histamine(2)-receptor antagonists (H(2)RA) suppress intragastric acidity independently of meals and help to control nocturnal acid breakthrough. Because proton pump inhibitors require an acid intragastric milieu for activation, nocturnal dosing of H(2)RA might decrease the effect of proton pump inhibitors taken in the morning by decreasing their gastric-acid-driven activation.

AIM

Assess intragastric acid control on omeprazole, 20 mg, taken every morning, after variable dosing of over-the-counter famotidine, 10 mg.

METHODS

Twelve Helicobacter pylori-negative, healthy volunteers received omeprazole, 20 mg, every morning before breakfast for 15 days. Baseline studies on omeprazole, 20 mg, in the morning, were done on day 7. On nights between days 8-9, 11-12 and 14-15, famotidine, 10 mg at bedtime, and 10 mg at bedtime and/or at 05.30 h, was given in a three-way, crossover, double-blind randomized design. Intragastric pH monitoring was performed on days 9, 12 and 15, starting at 08.00 h.

RESULTS

Percentage times intragastric pH < 4 on omeprazole, 20 mg, in the morning of the day after receiving famotidine, 10 mg, at bedtime (58.6 +/- 4.8); at 05.30 h (54.1 +/- 5.1); or at bedtime and at 05.30 h (54.3 +/- 5.0) did not differ significantly (P=0.65) from percentage times intragastric pH on day 7 of omeprazole, 20 mg, in the morning (49.5 +/- 5.1).

CONCLUSION

Concerns over inhibition of next-day daytime proton-pump inhibitor effect should not preclude use of nocturnal H(2)RAs in patients with gastro-oesophageal reflux disease.

Bedtime H2 blockers improve nocturnal gastric acid control in GERD patients on proton pump inhibitors

AIM

Proton pump inhibitors taken twice daily before meals (proton pump inhibitor b.d. AC) effectively controls daytime gastric pH; however, nocturnal gastric acid breakthrough (NAB) occurs in more than 75% of patients. Adding an H2-blocker at bedtime decreases NAB in normal subjects. The efficacy of this regimen has not been evaluated in GERD patients. The aim of this study was to assess the effects of proton pump inhibitor b.d., both with and without bedtime H2-blocker on intragastric pH and the occurrence of NAB in GERD patients.

METHODS

Prolonged ambulatory pH studies in GERD patients were reviewed. Group A: 60 patients (mean age 53 years, male 30) taking either omeprazole 20 mg or lansoprazole 30 mg b.d. Group B: 45 patients (mean age 49 years, male 23) on proton pump inhibitor b.d. (omeprazole 20 mg or lansoprazole 30 mg) plus an H2-blocker at bedtime (ranitidine 300 mg, famotidine 40 mg or nizatidine 300 mg). Eleven patients were evaluated during treatment with both regimens (group C). The percentage time of nocturnal and daytime intragastric pH > 4 and per cent of patients with gastric NAB were analysed. In the patients with NAB, its duration and associated oesophageal acid exposure also were analysed.

RESULTS

Median percentage time intragastric pH > 4 overnight was 51% in group A, compared to 96% in group B (P < 0.0001). Median percentage daytime pH > 4 was 73% in group A and 79.8% in group B (P=0.14). Median percentage time intragastric pH >p 4 overnight increased from 54.6% without H2RA to 96.5% after adding bedtime H2RA (P=0.0013) in group C patients. NAB occurred in 82% patients in group A and 40% in group B (P < 0.0001). The mean duration of oesophageal acid exposure during NAB was significantly shorter in group B (18 +/- 6 min) than in group A (42 +/- 9 min, P=0.04).

SUMMARY

Adding a bedtime H2-blocker to the treatment enhanced nocturnal gastric pH control and decreased NAB compared to the proton pump inhibitor b.d. regimen. A bedtime H2-blocker also decreased oesophageal acid exposure during NAB.

CONCLUSION

Adding a bedtime H2-blocker to a proton pump inhibitor b.d. regimen should be considered in patients who require continued nocturnal gastric acid control whilst taking proton pump inhibitor b.d.

Simultaneous intraesophageal impedance and pH measurement of acid and nonacid gastroesophageal reflux: effect of omeprazole

BACKGROUND & AIMS

Nonacid reflux may explain symptoms in acid-suppressed patients. Simultaneous intraesophageal impedance and pH measurement was used to evaluate the frequencies of postprandial acid and nonacid reflux before and after omeprazole administration.

METHODS

Twelve heartburn patients underwent two 2-hour studies of intraesophageal impedance and pH in the right lateral decubitus position after a refluxogenic meal; session 1 without medication, session 2 after 7 days of omeprazole twice daily. Acid and nonacid reflux were quantified.

RESULTS

Two hundred seventeen reflux episodes were detected before and 261 after omeprazole treatment (P > 0.05). Percentage of acid reflux decreased (from 45% to 3%, P = 0.02) and nonacid reflux increased (from 55% to 97%, P = 0.03) after omeprazole. Heartburn and acid taste were more commonly linked to acid reflux but were also produced by nonacid reflux. Regurgitation was reported equally in acid and nonacid reflux. Delta(pH) > 1 did not help predict the presence of symptoms during nonacid reflux.

CONCLUSIONS

During treatment with omeprazole, postprandial reflux becomes predominantly nonacid. Symptoms are more common with acid reflux but are also produced by nonacid reflux. Simultaneous intraesophageal impedance and pH may be useful in evaluating the role of nonacid reflux in symptoms that persist despite adequate acid suppression.

Histamine receptor antagonists, proton pump inhibitors and their combination in the treatment of gastro-oesophageal reflux disease

The medical treatment of gastro-oesophageal reflux disease is accomplished with the appropriate use of anti-secretory therapy, principally H(2)-receptor antagonists and proton pump inhibitors. In fact, there is a direct correlation between the length of time, in terms of the number of hours per day that the intragastric pH is above 4, and the healing of the oesophagitis. Nowadays, H(2)-receptor antagonists are of limited use as primary treatment, being inferior to proton pump inhibitors in both healing and symptom relief. Although the majority of patients can be effectively managed with carefully titrated doses of proton pump inhibitors, a small number will continue to show difficulty in the management of their disease, principally because of inadequate nocturnal acid control. These patients may benefit from a combination of proton pump inhibitors twice daily with an H(2)-receptor antagonist at bedtime. This article reviews the use of H(2)-antagonists, proton pump inhibitors and their combination in the management of the patient with gastro-oesophageal reflux disease.

Esophageal function testing using multichannel intraluminal impedance

Multichannel intraluminal impedance (MII) is a new technique for evaluation of bolus transport. We evaluated esophageal function using bolus transport time (BTT) and contraction wave velocity (CWV) of liquid, semisolid, and solid boluses. Ten healthy subjects underwent MII swallow evaluation with various boluses of sterile water (pH 5), applesauce, three different sized marshmallows, and iced and 130 degrees F water. The effect of bethanechol was also studied. There was no difference in BTT or CWV for all water volumes from 1 to 20 ml. There was significant linear increase of BTT with progressively larger volumes of applesauce, and BTT of applesauce was longer than for water. BTT was significantly longer with large marshmallows vs. small and medium and was longer than for water. BTT for iced water was similar to 130 degrees F water. Applesauce showed a significant linear decrease of CWV with progressively larger volumes and was slower than water. Marshmallow showed significantly slower CWV with the large vs. small, and CWV for ice water was significantly slower than 130 degrees F water. Therefore, BTT of liquid is constant, whereas BTT of semisolid and solid are volume dependent and longer than liquids. CWV of semisolids and solids are slower than liquids. CWV of cold liquids is slower than warm liquids. MII can be used as a discriminating test of esophageal function.