Reproducibility of ambulatory oesophageal pH monitoring

Clinical practice guidelines for esophageal ambulatory reflux monitoring in Chinese adults

Esophageal ambulatory reflux monitoring is the current gold standard for the diagnosis of gastroesophageal reflux disease (GERD). In order to facilitate standardized procedure and improve diagnostic accuracy, clinical guidelines for ambulatory esophageal reflux monitoring were developed based on thorough literature search and working group conference by experts in gastrointestinal motility. Indications, contraindications, methodology, and reporting of ambulatory esophageal reflux monitoring were discussed in these clinical guidelines.

Validation of the Lyon classification for GORD diagnosis: acid exposure time assessed by prolonged wireless pH monitoring in healthy controls and patients with erosive oesophagitis

OBJECTIVE

Acid exposure time (AET) from ambulatory pH studies and reflux oesophagitis are independent measurements used by the Lyon classification to diagnose GORD. This study aimed to validate AET reference ranges and diagnostic thresholds by analysis of 96-hour wireless pH studies from healthy, asymptomatic controls (HCs) and patients with and without oesophagitis.

DESIGN

HC and consecutive patients referred for wireless pH studies (off acid suppressants for >7 days) underwent 96-hour pH studies at two tertiary referral centres. Erosive oesophagitis was categorised by the Los Angeles (LA) classification. Linear regression and receiver operating curve (ROC) analysis were performed to define optimal diagnostic cut-offs.

RESULTS

Prolonged, 96-hour pH studies were completed in 39 HCs (age 28 (18-53) years, 72% female) and 944 patients (age 46 (16-85) years, 65% female), of whom 136 (14.5%) had reflux oesophagitis. Median AET in HC was 1.3% (upper 95th percentile 4.6%) for any study day and 2.6% (upper 95th percentile 6.9%) for the worst day (24-hour period) during the study. ROC analysis for average AET differentiated HC from patients with moderate-to-severe oesophagitis (LA BCD; sensitivity 87%, specificity 95%, positive predictive value (PPV) 59%, negative predictive value 99% for a cut-off AET of 4.3%; area under the receiver operating curve 0.95). Specificity was higher, but PPV was substantially lower for severe oesophagitis (LA CD). 'Worst-day' analysis provided similar results; however, day-to-day variability was high.

CONCLUSION

Diagnostic thresholds for average AET were identified that accurately discriminate between HCs and patients with erosive oesophagitis. The findings provide conditional support for diagnostic criteria for GORD proposed by the Lyon Consensus.

British Society of Gastroenterology guidelines for oesophageal manometry and oesophageal reflux monitoring

These guidelines on oesophageal manometry and gastro-oesophageal reflux monitoring supersede those produced in 2006. Since 2006 there have been significant technological advances, in particular, the development of high resolution manometry (HRM) and oesophageal impedance monitoring. The guidelines were developed by a guideline development group of patients and representatives of all the relevant professional groups using the Appraisal of Guidelines for Research and Evaluation (AGREE II) tool. A systematic literature search was performed and the GRADE (Grading of Recommendations Assessment, Development and Evaluation) tool was used to evaluate the quality of evidence and decide on the strength of the recommendations made. Key strong recommendations are made regarding the benefit of: (i) HRM over standard manometry in the investigation of dysphagia and, in particular, in characterising achalasia, (ii) adjunctive testing with larger volumes of water or solids during HRM, (iii) oesophageal manometry prior to antireflux surgery, (iv) pH/impedance monitoring in patients with reflux symptoms not responding to high dose proton pump inhibitors and (v) pH monitoring in all patients with reflux symptoms responsive to proton pump inhibitors in whom surgery is planned, but combined pH/impedance monitoring in those not responsive to proton pump inhibitors in whom surgery is planned. This work has been endorsed by the Clinical Services and Standards Committee of the British Society of Gastroenterology (BSG) under the auspices of the oesophageal section of the BSG.

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.

Long-term wireless pH monitoring of the distal esophagus: prolonging the test beyond 48 hours is unnecessary and may be misleading

Wireless pH monitoring of the esophagus has been widely used to detect GERD for more than a decade. It is generally well tolerated and accepted by patients, but it is still unclear whether prolonging a recording beyond the usual 48 hours can improve the test's diagnostic value. The aim of this study is to examine the diagnostic yield of 96-hour pH monitoring vis-à-vis 24- and 48-hour tests, and to ascertain whether any gain in diagnostic terms was of genuine clinical utility. Patients with suspected GERD underwent 4-day PPI-off wireless pH monitoring of the distal esophagus. The capsule was inserted under endoscopic control, 6 cm above the squamocolumnar junction. Average acid exposure time was calculated after 24, 48, and 96 hours of recording. Ninety-nine patients completed the 96 hour test, and formed the study sample. The wireless test method was used in 42 patients (42.4%) unable to tolerate the traditional pH-monitoring catheter, and in 57 (57.6%) with a previous negative pH study despite symptoms suggestive of GERD. On complete analysis, 47 patients (47.5%) had a pathological test result: 19 patients within the first 24 hours (19.2%, 24 hour group); another 16 after 48 hours (+16.2%, 48 hour group), and a further 12 (+12.1%, 96 hour group) only after 96 hours of monitoring. All 47 patients with an abnormal acid exposure were offered and accepted surgery (10 patients) or medical therapy (37 patients). Clinical follow-up was obtained in all patients with a positive Bravo test result after a median 67 months (IQR: 38-98) using a validated symptom questionnaire. A good outcome after fundoplication or medical therapy was achieved in 73.7% of patients in the 24 hour group, in 62.5% of those in the 48 hour group, and in only 25% of those in the 96 hour group, P = 0.02. Long-term wireless pH monitoring enables an increase in the diagnostic yield over traditional 24- and 48-hour pH studies, but prolonging the test may constitute an unwanted bias and prompt the recruitment of more complex patients, in whom the outcome of surgical or medical therapy may prove less than satisfactory. These findings should be taken into account when establishing the guidelines for assessing GERD with such long-term pH monitoring methods.

Yield of prolonged wireless pH monitoring in achalasia patients successfully treated with pneumatic dilation

BACKGROUND

Gastro-oesophageal reflux disease (GORD) is a long-term complication of achalasia treatments. The aim of our study was to evaluate the yield of prolonged wireless pH monitoring in patients with successfully treated achalasia and its influence on proton pump inhibitor (PPI) use.

METHODS

Twenty-five patients with achalasia who underwent prolonged wireless pH monitoring after a successful treatment with pneumatic dilation were enrolled. pH variables were analysed in the first 24 hours of monitoring to determine if tracings were indicative of GORD; the same variables were analysed in the following 24-hour period in order to obtain a worst-day diagnosis of GORD. PPI therapy before and after the test was recorded.

RESULTS

Five out of 25 patients had GORD diagnosis during the first day of monitoring and four of them had oesophagitis at endoscopy. During the following days of monitoring four more patients had a diagnosis of GORD. Out of the 25 patients, PPIs were started after the test in six asymptomatic GORD-positive ones, whereas prescription of PPIs was stopped without detrimental effect on symptoms in three GORD-negative patients.

CONCLUSIONS

Prolonged wireless pH monitoring is a useful test to be added to endoscopy in order to evaluate GORD and to optimise antisecretory treatment in successfully treated achalasia patients.

More art than science: impedance analysis prone to interpretation error

BACKGROUND

Impedance monitoring for reflux evaluation does not have standardized scoring, which can confound interpretation between observers. We investigated the variability of impedance testing interpretation between physicians and computer software.

METHODS

Raw impedance data from 38 patients that underwent impedance monitoring at a tertiary referral center between 2008 and 2013 were collected. Two physicians and computer software each analyzed the same impedance dataset for reflux activity and symptom-reflux correlation.

RESULTS

Normalized reflux activity interpretations did not differ between physicians and the computer for acid or non-acid reflux. However, for weakly acidic reflux, there was significant difference between physicians (p < 0.01) and between physician and computer (p < 0.01). In analyzing all reflux, significant variability existed between physicians (p < 0.01) but not between physician and computer. Variability in interpretation altered diagnosis in 24 % of patients when comparing between physicians, 18 % of patients when comparing both physicians to the computer, and an additional 24 % of cases when comparing a single physician to the computer. Symptom-reflux correlation differed in 7 % of physician-physician comparisons versus 8 % of computer-physician comparisons.

CONCLUSION

Impedance testing analysis is subject to marked variability between physicians and computer software, making impedance prone to interpretation error that can lead to differences in diagnosis and management.

Inconsistency in the Diagnosis of Functional Heartburn: Usefulness of Prolonged Wireless pH Monitoring in Patients With Proton Pump Inhibitor Refractory Gastroesophageal Reflux Disease

Background/Aims

The diagnosis of functional heartburn is important for management, however it stands on fragile pH monitoring variables, ie, acid exposure time varies from day to day and symptoms are often few or absent. Aim of this study was to investigate consistency of the diagnosis of functional heartburn in subsequent days using prolonged wireless pH monitoring and its impact on patients’ outcome.

Methods

Fifty proton pump inhibitotor refractory patients (11 male, 48 years [range, 38–57 years]) with a diagnosis of functional heart-burn according to Rome III in the first 24 hours of wireless pH monitoring were reviewed. pH variables were analysed in the following 24-hour periods to determine if tracings were indicative of diagnosis of non-erosive reflux disease (either acid exposure time > 5% or normal acid exposure time and symptom index ≥ 50%). Outcome was assessed by review of hospital files and/or telephone interview.

Results

Fifteen out of 50 patients had a pathological acid exposure time after the first day of monitoring (10 in the second day and 5 in subsequent days), which changed their diagnosis from functional heartburn to non-erosive reflux disease. Fifty-four percent of non-erosive reflux disease vs 11% of functional heartburn patients (P < 0.003) increased the dose of proton pump inhibitors or underwent fundoplication after the pH test. Outcome was positive in 77% of non-erosive reflux disease vs 43% of functional heartburn patients (P < 0.05).

Conclusions

One-third of patients classified as functional heartburn at 24-hour pH-monitoring can be re-classified as non-erosive reflux disease after a more prolonged pH recording period. This observation has a positive impact on patients’ management.

Pulsatile exposure to simulated reflux leads to changes in gene expression in a 3D model of oesophageal mucosa

Oesophageal exposure to duodenogastroesophageal refluxate is implicated in the development of Barrett's metaplasia (BM), with increased risk of progression to oesophageal adenocarcinoma. The literature proposes that reflux exposure activates NF-κB, driving the aberrant expression of intestine-specific caudal-related homeobox (CDX) genes. However, early events in the pathogenesis of BM from normal epithelium are poorly understood. To investigate this, our study subjected a 3D model of the normal human oesophageal mucosa to repeated, pulsatile exposure to specific bile components and examined changes in gene expression. Initial 2D experiments with a range of bile salts observed that taurochenodeoxycholate (TCDC) impacted upon NF-κB activation without causing cell death. Informed by this, the 3D oesophageal model was repeatedly exposed to TCDC in the presence and absence of acid, and the epithelial cells underwent gene expression profiling. We identified ~300 differentially expressed genes following each treatment, with a large and significant overlap between treatments. Enrichment analysis (Broad GSEA, DAVID and Metacore™; GeneGo Inc) identified multiple gene sets related to cell signalling, inflammation, proliferation, differentiation and cell adhesion. Specifically NF-κB activation, Wnt signalling, cell adhesion and targets for the transcription factors PTF1A and HNF4α were highlighted. Our data suggest that HNF4α isoform switching may be an early event in Barrett's pathogenesis. CDX1/2 targets were, however, not enriched, suggesting that although CDX1/2 activation reportedly plays a role in BM development, it may not be an initial event. Our findings highlight new areas for investigation in the earliest stages of BM pathogenesis of oesophageal diseases and new potential therapeutic targets.

Can multichannel intraluminal pH-impedance monitoring be limited to 3 hours? Comparison between ambulatory 24-hour and post-prandial 3-hour recording

Esophageal multichannel intraluminal pH-impedance recording (MII) is now a valid technique for determining the acidic, liquid, gas or mixed nature of gastroesophageal reflux episodes. However, some recordings may stop prematurely due to technical reasons or poor patient tolerance of the probe. Therefore, we questioned whether analysis of post-prandial 3-hour recording could predict the results obtained in ambulatory 24-hour recording. Fifty patients with symptoms of gastroesophageal reflux disease were investigated. For each patient, post-prandial 3-hour MII was recorded after a test meal, then followed by ambulatory 21-hour MII. Correlation between the total number of liquid reflux events in the 3-hour and 24-hour recordings was elevated (R=0.71; P<0.001), with better correlation for acid (R=0.80; P<0.001) and weak acid reflux (R=0.56; P<0.001) than non-acid reflux (R=0.44; P<0.01). Sensitivity and specificity of 3-hour recording in detecting elevated liquid reflux over 24 hours (id>75reflux/24 h) were 49% and 100%, respectively, for 8 or less liquid/mixed reflux events per 3 hours, and 78% and 88%, respectively for 15 or more liquid/mixed reflux events per 3 hours. The sensitivity and specificity of symptom association probability (SAP) calculated over 3 hours were 56% and 91%, respectively. In conclusion, we identified relevant indicators on the 3-hour post-prandial recording likely to give accurate prediction of absence or presence of gastroesophageal reflux disease from 24-hour MII recording.

Effect of nitrite delivered in saliva on postprandial gastro-esophageal function

OBJECTIVE

Acid reflux produces troublesome symptoms (heartburn) and complications including esophagitis, Barrett's esophagus, and adenocarcinoma. Reflux occurs due to excessive and inappropriate relaxation of the lower esophageal sphincter. An important mediator of this is nitric oxide, high concentrations of which are generated within the lumen when swallowed saliva meets gastric acid. Saliva contains nitrite, derived from the enterosalivary recirculation of dietary nitrate, which is reduced to nitric oxide by gastric acid. The aim of this study was to investigate whether salivary nitrite contributes to dysfunction of the lower esophageal sphincter.

MATERIALS AND METHODS

In 20 volunteers, studies of gastro-esophageal function were performed on four separate days, following consumption of a standardized meal, with saliva nitrite concentrations modified differently each day by intra-oral nitrite infusion.

RESULTS

The infusions produced an appropriate range in saliva nitrite concentrations, from below to well above the physiological range. The standardized meal induced expected physiological changes in gastro-esophageal function confirming the recordings were sensitive and robust. Esophageal acid exposure (primary outcome) was similar on each study day. Secondary outcomes, including number and duration of reflux events, rate of transient lower esophageal sphincter relaxations, lower esophageal sphincter pressure and rate of gastric emptying were also unaffected by variations in saliva nitrite concentration.

CONCLUSIONS

Nitrite in swallowed saliva does not modify gastro-esophageal junction function or predispose to gastro-esophageal reflux. The wide range in saliva nitrite concentrations, the sensitivity of the physiological recordings and the number of subjects studied make it very unlikely that an effect has been missed.

Wireless ambulatory pH studies: manometric or endoscopic guidance?

Wireless pH studies are widely used to assess the presence and severity of gastroesophageal reflux disease. We hypothesized that sedation or air insufflation during a preceding endoscopy may systematically alter results. A retrospective review of ambulatory pH studies completed between January 2008 and April 2010 was performed. The pH capsule was placed 6 cm above the endoscopically determined location of the squamocolumnar junction or 5 cm above the manometrically localized upper border of the lower esophageal sphincter (LES). A total of 356 patients (65% women) underwent pH studies using the BRAVO system (GIVEN Imaging, Yoqneam, Israel). In 186 patients (E-P), the capsule was placed during endoscopy. In 170 patients (M-P), capsule placement was based on manometric determination of LES boundaries using pharyngeal anesthesia only. Endoscopic placement was successful in all cases, whereas two patients could not tolerate capsule insertion with topical anesthesia only. The mean recording time did not differ between the two groups (E-P: 2468 ± 38 min; M-P: 2415 ± 40 min). The number of patients with abnormal findings on day 1 but normal results for day 2 was similar with 15% for E-P compared with 11% for M-P. However, there was a significant difference in total acid exposure times between days 1 and 2 for endoscopically (day 1: 7.3 ± 1.2; day 2: 4.8 ± 0.5; P < 0.01), but not manometrically based placement (day 1: 7.7 ± 0.7; day 2: 7.2 ± 0.6). There was no difference in the number of symptoms between days or groups (E-P day 1:13.4 ± 1.3; E-P day 2: 16.0 ± 1.6; M-P day 1: 14.1 ± 2.1; M-P day 2: 15.7 ± 2.0). Similarly, the symptom sensitivity index did not differ significantly between days and groups (E-P: day 1: 4.1 ± 0.5; day 2: 5.9 ± 0.8; M-P: day 5.3 ± 0.8; day 2: 5.7 ± 0.8). The majority of patients tolerate insertion of a wireless pH monitoring capsule without sedation. Unsedated placement did not negatively affect total recording times. Although endoscopy resulted in higher acid exposure on day one it did not significantly increase the overall fraction of abnormal tests. If confirmed in prospective studies, the more consistent findings and a potential to lower cost favor manometrically guided capsule placement.

Impact of prolonged 48-h wireless capsule esophageal pH monitoring on diagnosis of gastroesophageal reflux disease and evaluation of the relationship between symptoms and reflux episodes

CONTEXT

Gastroesophageal reflux disease is one of the most common digestive diseases and an important cause of distress to patients. Diagnosis of this condition can require ambulatory pH monitoring.

OBJECTIVES

To determine the diagnostic yield of a wireless ambulatory pH monitoring system of 48-hours, recording to diagnose daily variability of abnormal esophageal acid exposure and its symptom association.

METHODS

A total of 100 consecutive patients with persistent reflux symptoms underwent wireless pH capsule placement from 2004 to 2009. The wireless pH capsule was deployed 5 cm proximal to the squamocolumnar junction after lower esophageal sphincter was manometrically determined. The pH recordings over 48-h were obtained after uploading data to a computer from the receiver that recorded pH signals from the wireless pH capsule. The following parameters were analyzed: (1) percentual time of distal esophageal acid exposure; (2) symptom association probability related to acid reflux. The results between the first and the second day were compared, and the diagnostic yield reached when the second day monitoring was included.

RESULTS

Successful pH data over 48-h was obtained in 95% of patients. Nearly one quarter of patients experienced symptoms ranging from a foreign body sensation to chest pain. Forty-eight hours pH data analysis was statistically significant when compared to isolated analysis of day 1 and day 2. Study on day 2 identified seven patients (30.4%) that would be missed if only day 1 was analyzed. Three patients (18.7%) out of 16 patients with normal esophageal acid exposure on both days, showed positive symptom association probability, which generated an increase in diagnostic yield of 43.4%.

CONCLUSION

Esophageal pH monitoring with wireless capsule is safe, well tolerated, does not require sedation. The extended 48-h period of study poses an increased yield to diagnose gastroesophageal reflux disease patients.

Measurement of acid exposure of proximal esophagus: a better tool for diagnosing non-erosive reflux disease

BACKGROUND

The sensitivity of 24-h pH monitoring is poor in non-erosive reflux disease (NERD). In NERD patients, the proximal extent of acid reflux is one of the main determinants of reflux perception. The present study was aimed to compare the diagnostic accuracy of acid exposure time (AET), at 5 cm above the lower esophageal sphincter, with those at 10 cm and at 3 cm below the upper esophageal sphincter as well as the reproducibility of these parameters.

METHODS

A total of 93 consecutive NERD patients, with typical symptoms responsive to proton pump inhibitor treatment, and 40 controls underwent esophageal manometry and multi-channel 24-h pH-test; 13 patients underwent the same study on two occasions. Symptom association probability (SAP) values were evaluated at each esophageal level.

KEY RESULTS

The ROC curve indicates that the area under the curve was 0.79 at distal (SE=0.039), 0.87 (SE=0.032) at proximal (P=0.029 vs distal), and 0.85 (SE=0.033) at very proximal esophagus (P =0.148). AET showed a reproducibility of 61% (Kappa 0.22) at distal esophagus, 77% (Kappa 0.45) at proximal and 53% (Kappa 0.05) at very proximal esophagus. The percentage of patients with a positive SAP was not significantly different when assessed at the distal compared with the proximal esophagus.

CONCLUSIONS & INFERENCES

In NERD patients, the diagnostic yield of the pH test is significantly improved by the assessment of AET at the proximal esophagus. As this variable seems to be less affected by the day to day variability, it could be considered a reliable and useful diagnostic tool in NERD patients.

Impact of symptom-reflux association analysis on long-term outcome after Nissen fundoplication

BACKGROUND

A positive symptom association probability (SAP) is regarded as an important selection criterion for antireflux surgery by many physicians. However, no data corroborate the relationship between symptom-reflux association and outcome, nor is it clear what impact a negative SAP has on the outcome of antireflux surgery in patients with abnormal oesophageal acid exposure. This study compared long-term outcomes of Nissen fundoplication in patients with a negative versus positive SAP.

METHODS

Five-year outcome of Nissen fundoplication in patients with proton-pump inhibitor (PPI)-refractory reflux and pathological acid exposure was compared between those with (SAP+, 109) and without (SAP-, 29 patients) a positive symptom association. Symptoms, quality of life (QoL), PPI use, endoscopic findings, manometry and acid exposure were evaluated.

RESULTS

At 5 years' follow-up, relief of reflux symptoms (95 versus 87 per cent), reduction in PPI use (80 to 25 per cent versus 85 to 14 per cent; P < 0·050) and improvement in QoL were similar in the SAP- and SAP+ groups. Reduction in acid exposure time (13·4 to 1·6 per cent versus 11·1 to 0·2 per cent of total time; P < 0·010), improvement in oesophagitis (44 to 6 per cent versus 61 to 13 per cent; P < 0·050) and increase in lower oesophageal sphincter pressure were also comparable.

CONCLUSION

The subjective and objective outcomes of fundoplication in patients with pathological acid exposure are comparable among those with a positive and negative SAP. Patients with pathological acid exposure and a negative SAP can also benefit from antireflux surgery.

Comparison of a composite symptom score assessing both symptom frequency and severity with a score that assesses frequency alone: a preliminary study to develop a practical symptom score to detect gastro-oesophageal reflux disease in a resource-poor setting

BACKGROUND

There is a need for a practical instrument to screen for gastro-oesophageal reflux disease (GORD) in epidemiological studies.

OBJECTIVES

To develop a practical score to detect GORD and compare assessment of both symptom frequency and severity with frequency alone.

METHODS

One hundred patients with upper gastrointestinal symptoms and 150 volunteers with no such past history faced an interviewer-administered questionnaire assessing seven symptoms, graded for frequency and severity. Two scores were generated. Score 1, the sum of frequency of symptoms and score 2, the sum of products of frequency and severity of each. Internal consistency, test-retest reliability and criterion validity against 24-h pH monitoring were assessed. Cut-off scores were generated by receiver operating characteristic curves using scores of half the volunteers and patients selected randomly and validated on the other half.

RESULTS

Cut-off scores and area under the curve for score 1 were >/=10.5 and 0.93, and score 2 were >/=12.5 and 0.93, respectively. The sensitivity and specificity of diagnosing the disease in the remaining participants using score 1 was 89.7 and 92.4% and score 2 was 93.8 and 94.0%, respectively. The instrument had good internal consistency (Cronbach alpha = 0.73) and reliability (intraclass correlation coefficient of scores 1 and 2 were 0.94 and 0.95, respectively). Score 2 showed better correlation with 24-h pH monitoring parameters (Spearman's rank correlation, P = 0.01).

CONCLUSION

Our score is valid, reliable and can detect GORD with high sensitivity and specificity. A score assessing both frequency and severity of symptoms correlates better to an objective measure of GORD.

Patients with physiological acid exposure and positive symptom association scores: a distinct group within the GORD spectrum

Studies comparing pH-metrically well-characterized gastro-oesophageal reflux disease (GORD) patients with physiological reflux to GORD patients with pathological reflux, with regard to clinical and epidemiological data, are lacking. We included 273 GORD patients with pathological 24-h pH-monitoring (pH+), defined as pH<4 > or = 6% of time. A symptom index (SI) > or = 50% was considered positive, as well as a symptom association probability (SAP) > or = 95%. We included 84 GORD patients with physiological acid exposure (pH-) and a positive SI and/or SAP. Manometry and endoscopy reports were reviewed. Subjects completed questionnaires about demographics and medical history, functional dyspepsia and irritable bowel syndrome, the Nepean Dyspepsia Index symptom score and the RAND-36 quality of life scale. pH- patients were younger (45 vs 50 years, P = 0.003), more often female (60%vs 39%, P = 0.001), smoked more (31%vs 19%, P = 0.021) and reported proton pump inhibition failure more often (47%vs 32%, P = 0.027). A hypotensive lower oesophageal sphincter was less common in pH- patients (18%vs 34%, P = 0.008) and distal oesophageal contraction amplitude was higher (11 vs 9.5 kPa, P = 0.045). pH- patients had hiatal hernia and oesophagitis less often (48%vs 73%, P < 0.0005; 36%vs 54%, P = 0.012 respectively). pH- patients less often reported no other symptoms besides GORD (20%vs 34%, P = 0.015). pH- patients scored worse at the Nepean (reflux 19 vs 12 out of 39, P < 0.0005; dyspepsia 54 vs 38 out of 156, P < 0.0005). In the subgroup of patients who have physiological oesophageal acid exposure the enhancement of the perceived symptom burden appears to be the most important mechanism in GORD pathogenesis.

Gastroesophageal Reflux Disease: A Population Based Study

Background

The prevalence of gastroesophageal reflux disease varies in different parts of the world. There are no population based studies in Nigeria. The main objectives of this study were to determine the prevalence and risk factors for gastroesophageal reflux disease in a population of Nigerian medical students.

Methods

The Carlsson-Dent questionnaire was administered to medical students in the clinical phase of their training at the University of Nigeria, Enugu Campus. Some putative risk factors for gastroesophageal reflux disease were also included in the questionnaire.

Results

The prevalence of gastroesophageal reflux disease was 26.34%. There was an association between the use of caffeine-containing substances (coffee and kolanuts) and the prevalence of gastroesophageal reflux disease (odds ratio = 2.2 and 2.015, respectively).

Conclusions

Gastroesophageal reflux disease is common among Nigerian medical students. The use of caffeine-containing substances (coffee and kolanuts) by students may have a role in the high prevalence.

Comparison of wireless 48-h (Bravo) versus traditional ambulatory 24-h esophageal pH monitoring

OBJECTIVE

To compare wireless with catheter-based esophageal pH recordings.

MATERIAL AND METHODS

Forty-five patients with symptoms suggestive of gastroesophageal reflux disease and 47 healthy volunteers were investigated in a university-affiliated hospital; 48-h wireless esophageal pH recording was performed. During the first 24 h, simultaneous traditional pH recording by catheter was undertaken. Nine of the volunteers underwent repeated measurements with both techniques. Outcome measures were feasibility, agreement, concordance of diagnostic yield, reproducibility, and subjective symptoms.

RESULTS

Subjective parameters were less affected when using the wireless technique alone (p<0.05). On using the wireless technique, esophageal acid exposure was underestimated approximately by half compared with traditional recording (p<0.05). Although pH data obtained with the two techniques were correlated (r(2)=0.66, p<0.001), the range between limits of agreement was wide (-3.7 to 10.0 percentage units of total time pH <4). Coefficients of variation for repeated measurements were 60.1+/-26.3% for catheter recordings, and 66.0+/-47.3 for wireless recordings on day 1 (NS). Concordance of diagnostic yield was 81.5% with all subjects included.

CONCLUSIONS

Forty-eight-hour wireless Bravo pH monitoring is feasible but consistently underestimates esophageal acid exposure compared to the conventional technique. Although there is a significant correlation between the two techniques for pH recordings, the wide range in limits of agreement and the large coefficient of variation with both techniques suggest that the two methods are not immediately interchangeable for use in clinical practice.

Recurrent symptoms after fundoplication with a negative pH study--recurrent reflux or functional heartburn?

INTRODUCTION

A small cohort of patients present after antireflux surgery complaining of recurrent heartburn. Over two thirds of these patients will have a negative 24-h pH study. The aim of our study is to determine whether these patients have an associated functional disorder or abnormal cytokine activity and to examine the reproducibility of pH testing.

METHODS

A prospective analysis was carried out on a cohort of patients who had undergone a fundoplication and postoperative pH testing for recurrent heartburn: group A--patients with recurrent heartburn and a negative 24-h pH study and group B (control group)--patients with recurrent heartburn and a positive pH study. Questionnaires, a blood sample, and repeat pH testing were completed.

RESULTS

Sixty-nine patients were identified. Group A's depression score (8.6 +/- 4.1) was significantly higher than group B's (5.9 +/- 4.2; P = 0.03). Cytokine levels were similar in both groups. Forty-seven of 49 (96%) patients who underwent repeat pH testing had a negative study. Symptom-reflux correlation was highly significant (P < 0.001).

CONCLUSION

Some patients with recurrent heartburn and a negative pH study have associated functional or psychiatric comorbidities such as depression. Reproducibility of 24-h pH testing in these patients is excellent.

Reproducibility of symptom association analysis in ambulatory reflux monitoring

INTRODUCTION

The temporal relationship between reflux symptoms and reflux episodes during ambulatory reflux monitoring can be studied with symptom association analysis, and the strength of the relationship can be expressed using indices such as the SAP (symptom association probability), SI (symptom index), and SSI (symptom sensitivity index). The reproducibility of these indices has not been determined yet.

METHOD

Twenty-one patients with typical reflux symptoms (9 men, 53 [38-57] yr) underwent two 24-h combined pH-impedance recordings off acid-secretory medication with an interval of 1-4 wk. The SAP, SI, and SSI were calculated for each measurement. Reproducibility of these indices was determined with Kendall's coefficients of concordance.

RESULTS

The number of reflux events were highly reproducible (Kendall W = 0.92, P < 0.01). The number of symptoms related to reflux events was reproducible (Kendall W = 0.91, P < 0.01) while the number of reported reflux symptoms was not (Kendall W = 0.75, P= 0.07). The SAP and SSI were highly reproducible (Kendall W = 0.90, P= 0.01, and W = 0.86, P < 0.05, respectively) but the SI was not (W = 0.73, P= 0.09). The percentage of patients with similar outcomes on two separate test days for the SAP, SI, and SSI was 86%, 67%, and 86%, respectively.

DISCUSSION

In 24-h pH-impedance recordings of patients with reflux symptoms, the number of reflux events and the number of symptoms related to reflux events were highly reproducible as were the SAP and SSI. This supports the use of these indices to express the relationship between symptoms and reflux episodes in clinical practice.

Symptoms experienced during 24-h pH monitoring and their relationship to outcome after laparoscopic total fundoplication

Some patients having a 24-h pH monitoring test prior to laparoscopic fundoplication experience no symptoms at all in spite of having a positive test, and other patients experience only atypical symptoms in spite of having a positive test. This study investigates the postoperative outcome of such patients. All patients underwent esophageal manometry and 24-h esophageal pH monitoring before laparoscopic total fundoplication. Patients were divided into three groups based on their symptom profile recorded during a positive 24-h pH monitoring: those with typical symptoms (n = 104), those with atypical symptoms (n = 28) and those who experienced no symptoms at all (n = 23). The outcomes measured were heartburn score (0-10), dysphagia composite score (0-45) and satisfaction score (0-10) at 12 months after surgery. Outcome analysis reveals the heartburn scores were significantly reduced postoperatively for all groups of patients. At 1 year after surgery, there was no difference among the three groups of patients in terms of heartburn score and dysphagia composite scores, nor the experience of bloating, belching, or their willingness to repeat surgery. Despite one group experiencing no symptoms, and another group atypical symptoms during a positive pH study, the postoperative satisfaction scores for these two groups was good, but significantly less (P = 0.03, P = 0.02, respectively) than the group of patients with a typical symptom index. In conclusion, patients who experience only atypical symptoms or no symptoms at all during their preoperative positive 24-h pH monitoring may still obtain a good result from antireflux surgery. However, these symptom profiles should alert the surgeon that such patients may have an outcome which is not as good as patients who experience only typical symptoms during a pH study.

Acid reflux detection and symptom-reflux association using 4-day wireless pH recording combining 48-hour periods off and on PPI therapy

OBJECTIVES

Studies have shown that extended pH recording improves the sensitivity of esophageal pH monitoring. Controversy exists as to whether pH studies are optimally done off or on proton pump inhibitor (PPI) therapy. The aim of this study was to incorporate periods both off and on PPI therapy in a single, extended pH test and describe the effect of PPI therapy on symptom-reflux associations.

METHODS

Sixty patients underwent 4-day pH recordings using two separate receivers calibrated to a single wireless pH capsule. Patients were off PPI therapy for days 1 and 2. Either rabeprazole 20 mg twice daily or omeprazole/sodium bicarbonate 40 mg twice daily were administered on days 3 and 4. Symptom-reflux correlation was determined by the symptom index (SI), symptom sensitivity index (SSI), and symptom association probability (SAP).

RESULTS

Twenty studies were excluded due to premature detachment (9) or incomplete data capture for >6 of the 96-h period (11). Off therapy, 14 patients (35%) had abnormal esophageal acid exposure values. On day 4, 39 patients (98%) had normal acid exposure. The number of symptoms and acid reflux events were significantly higher off PPI therapy. Furthermore, the percentage of patients with a positive SI fell from 50% off PPI to 9% on PPI (P < 0.01), whereas 63% of patients symptomatic off PPI therapy became asymptomatic on PPI therapy and could not have an SI calculated. Similarly, the SAP was abnormal in 45% of patients off PPI therapy but only 10% on PPI therapy (P < 0.01).

CONCLUSIONS

Extended pH recording improves the detection of abnormal acid reflux and increases the number of recorded symptoms and acid reflux events. Combined off and on PPI therapy pH testing enhances the interpretation of pH monitoring and symptom-reflux correlations, which can be helpful in the management of patients with PPI-unresponsive gastroesophageal acid reflux symptoms.

pH Testing: the basics

Esophageal pH testing, first described more than 3 decades ago, has become incorporated in the diagnostic armamentarium of most gastroenterologists. Using commercially available sophisticated equipment and software, the procedure is easy to perform and the analysis of the signals is automated. Nevertheless, users of esophageal pH testing must remain aware of the technical pitfalls that may stand in the way of the acquisition of meaningful results. Esophageal pH monitoring provides quantitative information about the exposure of the distal esophagus to acid. The technique makes it also possible, however, to quantify the correlation between symptom episodes and reflux events. In clinical practice, the latter is often more relevant than information on esophageal acid exposure.

The impact of prolonged pH measurements on the diagnosis of gastroesophageal reflux disease: 4-day wireless pH studies

INTRODUCTION

Prolonged, 4-day (96 h) measurement by the wireless Bravo system provides an opportunity to assess the variance, diagnostic reproducibility, and yield of 24- and 48-h pH and symptom association studies.

METHOD

Retrospective analysis of 83 patients with suspected reflux symptoms undergoing wireless pH monitoring with the intention of 96-h measurement. Study periods were classified based on esophageal acid exposure, the DeMeester score (DMS), and the association of reflux events and symptoms (symptom index). The technical success of prolonged pH recording and diagnostic accuracy of 24-, 48-, and 72-h pH studies compared to the 96-h "gold standard" were assessed.

RESULTS

Prolonged Bravo pH studies were possible and well tolerated in routine clinical practice. Complete 96-h recordings were available for 34/83 (41%) patients. Variation in pH measurements reduced with increasing study duration (24-h 45%vs 48-h 27%, P<0.01), but no change in reflux severity over time was observed (ANOVA, P=ns). Abnormal acid exposure was found in 7 (19%) on every test day and 21 (58%) on at least one of four test days. A diagnosis consistent with the 96-h "gold standard" was present in 22 (63%), 29 (83%), and 32 (91%) patients for 24-, 48-, and 72-h test periods, respectively, with a significant improvement of diagnostic sensitivity with study duration (P<0.01). Similar findings were present for symptom association.

CONCLUSION

Increasing the duration of pH studies progressively improves measurement variance and the diagnostic reproducibility of reflux studies. Future studies must address the impact of prolonged pH studies on clinical management.

Clinical trial: the effects of adding ranitidine at night to twice daily omeprazole therapy on nocturnal acid breakthrough and acid reflux in patients with systemic sclerosis--a randomized controlled, cross-over trial

BACKGROUND

Gastro-oesophageal reflux disease (GERD) is an important problem in systemic sclerosis due to impaired salivation and oesophageal function.

AIM

To determine the efficacy of adding ranitidine at bedtime to control nocturnal acid breakthrough (NAB) and GERD in patients with systemic sclerosis already prescribed high-dose omeprazole.

METHODS

Patients with systemic sclerosis and GERD symptoms (n = 14) were treated with omeprazole 20 mg b.d. and either placebo or ranitidine 300 mg at bedtime for 6 weeks in a randomized, cross-over, placebo controlled study. At the end of each period a 24 h pH-study with intragastric and oesophageal pH measurement was performed.

RESULTS

Pathological acid reflux occurred in eight patients with omeprazole/placebo and in seven with omeprazole/ranitidine (P = ns) with technically adequate oesophageal pH-studies (n = 13). NAB was present in eight patients with omeprazole/placebo and six with omeprazole/ranitidine (P = ns) in whom technically adequate gastric pH-studies were obtained (n = 10). The addition of ranitidine had no consistent effect on patient symptoms or quality of life.

CONCLUSION

Many patients with systemic sclerosis experienced NAB and pathological oesophageal acid exposure despite high-dose acid suppression with omeprazole b.d. Adding ranitidine at bedtime did not improve NAB, GERD or quality of life in this population.

Determinants of Abnormal Supine Reflux in 24-Hour pH Recordings

A previous study showed that supine gastroesophageal reflux occurs mainly in the early nighttime period and is greater if the patient retires within 2 hr of a meal. We analyzed 306 consecutive esophageal pH studies between January and July 2003. Ninety-two patients had abnormal supine reflux. The recumbent period was divided into quarters (Q1-Q4) and reflux parameters were calculated for each period. Reflux was maximal in Q1, and decreased progressively from Q1 to Q4 (P<0.001). Median time between evening meal and retiring was no different from that for 44 upright gastroesophageal reflux patients. Patients retiring within 2 hr of a meal had a higher percentage supine reflux time (P=0.012), but no increase in reflux was observed in those retiring within 3 hr. Supine reflux occurs maximally in the early nighttime period. Although not fully explained as a postprandial phenomenon, these patients should avoid going to bed within 3 hr of a meal.

ACG practice guidelines: esophageal reflux testing

Investigations and technical advances have enhanced our understanding and management of gastroesophageal reflux disease. The recognition of the prevalence and importance of patients with endoscopy-negative reflux disease as well as those refractory to proton pump inhibitor therapy have led to an increasing need for objective tests of esophageal reflux. Guidelines for esophageal reflux testing are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee and approved by the Board of Trustees. Issues regarding the utilization of conventional, catheter-based pH monitoring are discussed. Improvements in the interpretation of esophageal pH recordings through the use of symptom-reflux association analyses as well as limitations gleaned from recent studies are reviewed. The clinical utility of pH recordings in the proximal esophagus and stomach is examined. Newly introduced techniques of duodenogastroesophageal reflux, wireless pH capsule monitoring and esophageal impedance testing are assessed and put into the context of traditional methodology. Finally, recommendations on the clinical applications of esophageal reflux testing are presented.

Impedance monitoring shows that posture and a meal influence gastro-oesophageal reflux composition and frequency

Impedance monitoring determines reflux composition as liquid and/or gas, and we assess with impedance the effect of posture and a meal on reflux composition. Twenty-nine gastro-oesophageal reflux disease (GORD) patients and 10 normal volunteers underwent simultaneous impedance, manometry and pH for three 40-min periods, each 20-min upright, 10-min left side and 10-min right side. One period was fasting, and two postprandial. We found that reflux event composition on the right side was liquid-only near exclusively (93%). In contrast, 85% of reflux on the left side and 74% upright was gas-only or liquid and gas (P < 0.001). More gas-only reflux occurred fasting (80%) than postprandial (P < 0.01). Reflux composition was similar in the study groups and two postprandial periods (P > 0.25). After confirming gas reflux suppression on the right side, a pilot study assessed gastric anatomy as a cause. Five achalasia patients had fluid injected into the stomach at endoscopy, and the EG junction was submerged below liquid-only on the right side. We conclude that reflux is nearly always liquid-only on the right side where the EG junction may be below fluid. Reflux fasting is usually gas-only. Different posture and fasting times may (i) explain variations in acid exposure during pH monitoring and (ii) promote or prevent GORD symptoms.

Oesophageal pH monitoring using the Bravo catheter-free radio capsule

OBJECTIVES

Oesophageal pH monitoring is the current standard for the diagnosis of gastro-oesophageal reflux disease. The Bravo capsule allows 48-h monitoring without the need for a naso-oesophageal catheter. Our aim was to assess the Bravo capsule in terms of patient discomfort and interference with daily activities, and to determine if 48-h Bravo pH studies facilitate the diagnosis of gastro-oesophageal reflux disease.

METHODS

Ambulatory pH studies were performed at two hospitals using either the Bravo capsule (n=100) or a conventional naso-oesophageal catheter (n=100). Participants were selected either for investigation of symptoms suggestive of gastro-oesophageal reflux disease, or to follow-up antireflux surgery. All participants completed questionnaires to assess discomfort and interference with daily activities.

RESULTS

Eighty-nine Bravo studies recorded at least 48 h of data, and 95 were diagnostic. Bravo participants reported significantly less discomfort during insertion (P<0.0001) and monitoring (P<0.0001), and less interference with daily activities (P<0.0001), eating (P<0.005), sleeping (P<0.0001) and work (P<0.0001). No significant difference was observed between day 1 and 2 median total time pH<4 (4.0 and 4.3%, P=0.64), erect time pH<4 (5.0 and 5.0%, P=0.56), supine time pH<4 (0.5 and 0.5%, P=0.23), and Johnson-DeMeester scores (15.9 and 16.2, P=0.90). Ten Bravo participants (10%) were diagnosed with gastro-oesophageal reflux disease using day 2 data after a normal day 1.

CONCLUSIONS

The Bravo capsule significantly reduces the patient discomfort and interference with normal daily activities during pH monitoring associated with a naso-oesophageal catheter. Moreover, 48-h Bravo studies offer an advantage over conventional 24-h studies in diagnosing gastro-oesophageal reflux disease.

Day-to-day variability in acid reflux patterns using the BRAVO pH monitoring system

BACKGROUND & GOALS

The wireless pH monitoring system such as the BRAVO pH system is a significant advancement in the evaluation of patients with gastroesophageal reflux because of its potentially better tolerability and the ability to record data over a 48-hour period. The aim of our study was to evaluate safety, performance, tolerability, and day-to-day variability in acid reflux patterns using the BRAVO pH system.

METHODS

A total of 90 consecutive patients (48 men and 42 women) with persistent reflux symptoms underwent BRAVO pH capsule placement from October 2002 to August 2003 at a tertiary care hospital. The BRAVO pH capsule was deployed 6 cm proximal to the squamocolumnar junction under endoscopic guidance. The pH recordings over 48 hours were obtained after uploading data to a computer from the pager-like device that recorded pH signals from the BRAVO pH capsule.

RESULTS

Successful pH data over 48 hours was obtained in 90% of patients. Nearly two thirds of patients experienced a variety of symptoms ranging from a foreign body sensation to chest discomfort or pain. Four patients had severe chest pain, 3 of whom required endoscopic removal of the BRAVO pH capsule. In 74.4% of patients, number of reflux events as well as time (%) pH<4 correlated from the first 24-hour period to the second 24-hour period. However, in 28% of patients, no predictable pattern of (%) time pH<4 in the supine position was reproduced from one 24-hour period to the next 24-hour period.

CONCLUSIONS

The BRAVO pH system appears a safe and effective method of recording esophageal acid exposure. It is an acceptable alternative for patients who are unwilling or unable to tolerate nasopharyngeal catheter-based pH studies, and it has a potential advantage of the 2-day recording period.

Acid reflux event detection using the Bravo wireless versus the Slimline catheter pH systems: why are the numbers so different?

OBJECTIVE

This study analysed the relative accuracy of the Bravo wireless and the Slimline catheter-Mark III Digitrapper pH systems in the detection of acid reflux events.

METHODS

Twenty five asymptomatic subjects were studied. A Bravo capsule was placed 6 cm above the squamocolumnar junction (SCJ), marked by an endoclip, and a Slimline pH catheter was placed 5 cm above the manometrically localised lower oesophageal sphincter. The distance between the SCJ and each pH electrode was measured fluoroscopically. An in vivo pH reference was established using swallows of orange juice (pH 3.88). Concurrent pH data from the two systems were analysed in Excel spreadsheets.

RESULTS

Significantly more acid reflux events were reported by the Digitrapper system than the Bravo system (117.0 v 41.8). This was not explained by electrode position as there was no difference in median distance between the SCJ and either pH electrode (7.25 cm v 7.08 cm). The dominant source of discrepancy between systems was inaccuracy in electrode calibration and, after adjustment using the in vivo orange juice pH measurement, the discrepancy improved by 40%. However, discrepancy still existed and was most pronounced with short reflux events (1-15 s for the catheter, 1-17 s for the Bravo) associated with minimal intraoesophageal acidity and poor concordance between systems.

CONCLUSION

Substantially more reflux events were reported by the Digitrapper system compared with the Bravo system; 40% of excess events were attributable to a flawed software scheme for electrode thermal calibration while most of the remainder were brief events with poor reproducibility between systems.

[Correct diagnosis for indication in gastroesophageal reflux disease]

For diagnosis and quantitation of gastroesophageal reflux disease, a number of different examinations are available. The simplest are the patient's history and complaints as well as the proton pump inhibitor test; both methods have a positive predictive value of 65% to 70%. Esophagogastroduodenoscopy is the gold standard for differentiation between erosive and nonerosive reflux disease. Biopsy does not enhance the significance of endoscopy except for proof of Barrett's epithelium or malignant degeneration. Twenty-four-hour pH monitoring has the highest sensitivity and specificity for the diagnosis of gastroesophageal reflux disease. Barium swallow provides only additional information concerning hiatal hernia or stenosis. Manometry can clarify lower esophageal sphincter insufficiency or motility disorders of the tubular esophagus. However, the available studies show that manometry has no influence on postoperative outcome after fundoplication. The indication for medical therapy can primarily be based only on the history and complaints of the patient. As surgical therapy affords a high degree of diagnostic accuracy, at least endoscopy and 24-h pH monitoring are necessary for indication.

Tolerance and reliability of wireless pH monitoring in children

OBJECTIVES

The purpose of this study was to determine whether the placement of a wireless capsule pH monitoring system improved the reproducibility and patient comfort of pH probe studies in children.

METHODS

The records of 50 children who underwent wireless pH monitoring were retrospectively reviewed. Among this group, 44 children (27 males and 17 females) met inclusion criteria. The average age was 11.8 years, with a range from 6 years to 19 years. Each of these patients had a capsule placed 6 cm above the squamocolumnar junction and underwent pH telemetry for 2 days. In addition, 38 of the 44 families were contacted for follow-up to determine the tolerability of the catheter-free monitoring.

RESULTS

Data analysis revealed that the overall reproducibility of a single 24 hour period was 77%. Studies were considered reproducible if the reflux index was normal (pH <4 for less than 5% of study period) or abnormal on both study days. Using McNemar's exact test, we found no significant difference between the two days (P = 0.11). Ten of 44 patients had conflicting results on day 1 compared with results on day 2. The majority (68%) of patients reported some degree of discomfort during the study; however, this pain was generally mild. Ninety-five percent of parents would be willing to have their child undergo pH monitoring in the future with the wireless pH monitoring.

CONCLUSIONS

Catheter-free prolonged esophageal pH monitoring is feasible in children older than 6 years of age. A lack of consistent reproducibility in sequential 24 hour recordings with this technique concurs with findings using the conventional catheter methodologies. The catheter-free system is often associated with discomfort during the study, but these symptoms were generally well tolerated.

Reproducibility of multichannel intraluminal electrical impedance monitoring of gastroesophageal reflux

OBJECTIVE

Esophageal impedance measurement is a novel method for gastroesophageal reflux monitoring. Reproducibility is an important aspect of every biomedical test. The aim of this study was therefore to asses the reproducibility of gastroesophageal reflux monitoring using impedance measurements.

METHODS

Impedance and pH signals were recorded in 20 healthy volunteers during 90-min postprandial periods on two separate days. Hourly rates of gas, liquid, and mixed gas-liquid reflux episodes were measured in each recording period as well as percentage of time with pH < 4 and rate of acid reflux episodes. As a quantitative description of inter- and intraindividual variation for each variable, the mean percentage of covariation (100 x SD/mean: %COV) was calculated. As a second measure for reproducibility, Kendall's coefficients of concordance (W values) were calculated.

RESULTS

For all variables, interindividual %COV was at least 50% higher than intraindividual %COV. Statistically significant concordances were found for gas reflux (W = 0.81, p= 0.04) and mixed reflux (W = 0.85, p= 0.03) while concordance for liquid reflux tended to be significant (W = 0.75, p= 0.08). This was comparable to the reproducibility of the number of acid reflux episodes and percentage of time with pH < 4 (W = 0.78, p= 0.05 and W = 0.88, p= 0.02, respectively).

CONCLUSIONS

Postprandial gastroesophageal reflux data assessed with impedance monitoring are as reproducible as assessed with pH monitoring.

Clinical relevance of esophageal and gastric pH measurements in patients with gastro-esophageal reflux disease (GERD)

BACKGROUND

Gastro-esophageal reflux disease (GERD) is a highly prevalent disease caused by the exposure of the esophagus to refluxed gastric contents. Proton pump inhibitors (PPIs) are the mainstay of current treatment. At present, the assessment of the efficacy of different PPIs in the treatment of GERD employs two measures: esophageal and gastric pH monitoring. Esophageal pH monitoring is the most accurate method of detecting reflux episodes and, therefore, its role as a diagnostic modality is well accepted. Gastric pH monitoring, on the other hand, is an accurate measure of gastric acid pH, but its relevance to patients with GERD is questionable, since recordings correlate poorly with esophageal acid exposure.

OBJECTIVE

This paper reviews (based on a Medline literature search, 1980-2004) the clinical relevance of esophageal and gastric pH measurements in both the management of GERD and in the evaluation of the efficacy of PPI therapy.

FINDINGS AND CONCLUSIONS

Evidence presented suggests that the assessment of esophageal pH yields data of greater relevance to patients with GERD than does data from gastric pH. This largely arises from the fact that esophageal pH monitoring assesses the pH of the refluxate and the frequency of reflux episodes at the mucosal site affected by the disease. The use of esophageal pH monitoring is recommended in patients who fail to present with endoscopic evidence of esophagitis, those with extra-esophageal symptoms, those who have failed traditional anti-reflux therapies, and those who are potential candidates for anti-reflux surgery. In recent years, the technique has benefited from the development of a wireless pH probe, and there is also an increasing body of evidence supporting its use in combination with other emerging technologies, such as Bilitec monitoring and multichannel intraluminal impedance. Such an approach is anticipated to aid both the diagnosis of GERD and the characterization of gastro-esophageal reflux (GER) in these patients.

Fundoplication for laryngopharyngeal reflux disease

BACKGROUND

Laryngopharyngeal reflux (LPR) disease arises from the effects of refluxed gastric contents on the proximal aerodigestive tract. LPR patients are often lumped into the category of "atypical" reflux. LPR symptoms are hoarseness, globus, cough, and pharyngitis. Severe disease is associated with subglottic stenosis and laryngeal cancer. Treatment includes lifestyle modifications and medications. The role of fundoplication for LPR has yet to be defined.

STUDY DESIGN

Forty-one patients underwent fundoplication for LPR. They were prospectively followed with three outcomes measures: The Reflux Symptom Index, a laryngoscopic grading scale (Reflux Finding Score), and a reflux-based specific quality-of-life scale.

RESULTS

Average early followup was at 4 months and late followup was at 14 months. The Reflux Symptom Index improved by 5.4 early (p < 0.05) and 6.5 late (p < 0.05). Improvement between early and late periods approached significance (p < 0.09). Reflux Finding Score improved 3.8 (p < 0.05) early and 4.4 (p < 0.05) late. The Quality of Life Index improved 0.6 early and 2.3 (p < 0.05) late. By Reflux Symptom Index criteria, 26 patients were improved early versus 35 late (p < 0.05). Factors associated with poor outcomes were structural laryngeal changes in five patients (p < 0.05) and no response to proton pump inhibitors in six patients (p < 0.05).

CONCLUSIONS

Fundoplication augments treatment of LPR. Improvement of symptoms continues past the first 4 months. Laryngoscopy is critical in patient selection because selected findings are associated with outcomes, diagnosis, and management.

pH probe positioning for 24-hour pH-metry by manometry or pH step-up

OBJECTIVES

Before pH measurement, manometry is recommended for precise pH probe positioning. We investigated whether the pH probe could be positioned accurately by the pH difference between the oesophagus and the stomach (pH step-up).

METHODS

Dual-channel 24-h pH-metry with probes positioned 5 cm above either the manometrically determined upper lower oesophageal sphincter margin or the pH step-up was performed in healthy volunteers and reflux patients. To determine the pH step-up, the pH probe was pulled back from the stomach until a sudden rise to pH greater than four occurred. Probe position, reflux episodes and the fraction of the time pH was less than four were compared using the Wilcoxon test for difference and the Hodges-Lehman estimate inclusive confidence interval for equivalence. The pH step-up method was evaluated further during proton pump inhibitor therapy and after drug discontinuation.

RESULTS

The pH probe was positioned 2 cm and 1 cm closer to the stomach by the pH step-up method in the volunteers and reflux patients, respectively. A small increase in upright reflux episodes but not in supine reflux episodes was registered by the probe positioned by pH step-up. No significant differences in the fraction of the time pH was less than four were obtained between the two probes. The Hodges-Lehman calculation proved equivalence for both methods of probe positioning for 24-h pH-metry. During proton pump inhibitor therapy, no pH step-up was detectable in three volunteers and in one patient. On the first day after discontinuing therapy, the pH step-up method yielded clear-cut results again.

CONCLUSION

The pH probe for diagnostic 24-h pH-metry and, with some limitations, also for 24-h pH-metry for therapy control, can be positioned accurately by the pH step-up method.

Unsolved problems in the management of patients with gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease is a common problem that brings large numbers of patients to physicians every day. It lowers the quality of life of affected individuals and exposes them to potentially dangerous complications. An increasing awareness exists among patients, doctors and authorities about the relevance of this pathological condition. Despite an improved understanding of many aspects of gastro-oesophageal reflux disease, clinical management of several cases is still unsatisfactory. Atypical cases with extra-oesophageal manifestations often defy diagnosis. Even typical symptoms are often misunderstood and considered to be part of the poorly defined area of dyspepsia by both patients and doctors. As a consequence, management remains uncertain for too many cases. If correctly diagnosed, gastro-oesophageal reflux disease can be efficaciously treated with proton pump inhibitors (PPIs). Although standard doses of PPIs can heal mucosal lesions and provide symptom relief in the vast majority of oesophagitis patients, non-oesophagitis symptomatic individuals and those with extra-oesophageal manifestations may fail to respond to similar regimens. Antireflux surgery is a possible alternative to PPI therapy, but it is hampered by complications in a substantial percentage of cases and by sporadic casualties even when performed by experienced surgeons. The high prevalence of gastro-oesophageal reflux disease in the general population and the relatively high management costs should prompt any doctor to seek the best possible therapeutic approach.

Intra-esophageal pH probe movement during eating and talking. A videoradiographic study

PURPOSE

To registrate the oscillations of the pH probe in the esophagus during phonation and swallowing in the erect and supine positions.

MATERIAL AND METHOD

Sixty-seven patients with suspicion of gastroesophageal reflux disease underwent manometry, 24-h pH monitoring, and videoradiography. In 43 patients the effect of dry, wet, and solid swallows in the erect and supine positions was determined, making a total of 258 swallows. In another 24 patients the effect of pH probe movement during phonation was studied.

RESULTS

During every swallow the probe moved in the proximal direction from 0.5 to 2.0 cm, returned to baseline, and in 48 swallows an additional descendent movement of up to 2.0 cm was seen, the last mentioned more pronounced during solid swallows. In the erect position, no significant difference was observed for the different swallowing types, whereas in the supine position, movements were significantly more pronounced during solid food swallows. During phonation the pH probe only ascended and returned to the baseline, with no descending part.

CONCLUSION

The pH probe movements are dependent on body position, bolus size, bolus composition, and talking. The ascending movements can only partially compensate for the esophageal shortening during swallow because of the time difference, and could perhaps explain the variation in results and reproducibility of 24-h pH monitoring.

Functional Heartburn

Functional heartburn is defined as the presence of a retrosternal burning sensation in the absence of pathologic gastroesophageal reflux. The underlying pathophysiology seems to be heterogeneous. In a subset of patients, esophageal hypersensitivity to physiologic esophageal acid exposure is involved, and this is likely to respond to intensive antireflux treatment. Antireflux surgery was not studied systematically in these patients and should be considered only in exceptional cases. In the remaining patients, non-acid reflux, esophageal mechanosensitivity, and psychological factors may be involved. Treatment options in these patients are limited owing to a lack of studies. Emerging therapies include selective serotonin reuptake inhibitors and relaxation therapy.

Definitions of reflux disease and its separation from dyspepsia

Management strategies for reflux disease are very different from those for dyspepsia and so differentiating between patients with "true" dyspepsia and those whose primary symptom is heartburn is a key step in their management. This separation has become more clear during the last decade as insights into reflux disease and dyspepsia have improved. It is likely that the use of short self administered questionnaires in routine clinical care will improve the reliability of separation of reflux induced symptoms from true dyspepsia.

Ambulatory esophageal pH monitoring: technique, interpretations, and clinical indications

Gastroesophageal reflux disease (GERD) is the most common esophageal disorder and perhaps among the most prevalent conditions seen in the primary care setting. The clinical manifestations of GERD, typical or atypical, such as noncardiac chest pain, respiratory or ear, nose, and throat symptoms, result from the reflux of gastric contents into the esophagus. Thus the clinical spectrum is wide and requires accurate diagnosis. Ambulatory 24-hr esophageal pH monitoring is not useful in all patients suspected to have GERD. This review describes the technique of ambulatory 24-hr esophageal pH monitoring, the interpretation of findings, and clinical applications of this test.

Laparoscopic fundoplication for patients with symptoms but no objective evidence of gastroesophageal reflux

In general terms, all patients who undergo a laparoscopic fundoplication procedure should have objective evidence of gastroesophageal reflux. However, occasionally patients without objective evidence of reflux disease are referred for surgery. This study assessed the outcome of a highly selected group of patients who underwent laparoscopic fundoplication without objective evidence of reflux at either preoperative endoscopy or pH monitoring. Data from all patients undergoing laparoscopic fundoplication in our department over a 9-year period from December 1991 to January 2001 were collected prospectively. From a total of 1,003 patients, a subgroup of 15 patients was identified who had no evidence of ulcerative oesophagitis at endoscopy or abnormal reflux on 24-h pH monitoring. Eight of these patients had typical symptoms of reflux (four had predominantly heartburn, four had predominantly volume regurgitation) and seven patients had atypical symptoms such as cough, bloating, chest pain, or sore throat. All patients had tried medication for acid suppression before surgery, with five gaining little or no benefit. The mean acid exposure time was 2% (range 0.1-3.6%). A correlation between typical symptoms and reflux events of over 50% was noted in three patients. All patients underwent laparoscopic fundoplication, with one conversion to an open procedure. Mean patient satisfaction score (0-10 linear score) was 8.7 at 3 months and 1 year postoperatively. Three patients failed to improve following surgery. These three all had atypical symptoms, a symptom correlation of less than 50% with acid reflux on pH monitoring, and two of the three had a poor response to medication. All other patients benefited symptomatically from surgery. We concluded that the absence of objective evidence of reflux should not always preclude patients from a laparoscopic fundoplication. Carefully selected patients with typical reflux symptoms can have a good outcome. However, patients who do not have typical symptoms and who respond poorly to acid suppression are not likely to benefit from surgery.

Twenty-four hour pH monitoring in the assessment of esophageal function

Ambulatory 24-hour esophageal pH monitoring is an important test in the management of patients with gastroesophageal reflux disease. It quantifies esophageal acid exposure while patients pursue their everyday activities without restrictions. The test is performed with a compact portable data logger, miniature pH electrode, and computerized data analysis. The pH electrode should be positioned 5 cm above the manometrically defined lower esophageal sphincter. The patient is asked to press a button on the data logger indicating the onset of the symptom in question, which allows symptoms and acid reflux correlation. Twenty-four hour pH monitoring is generally performed after a therapeutic trial of antireflux medications, preferably proton pump inhibitors.