Oesophageal pH monitoring using the Bravo catheter-free radio capsule

Prolonged wireless pH monitoring increases diagnostic yield in patients with reflux symptoms and borderline 24-hour impedance pH

The Lyon Consensus defines pathological gastroesophageal reflux disease (GERD) as an acid exposure time (AET) greater than 6%, while AET less than 4% rules it out. AET between 4% and 6% is borderline. Prolonged wireless capsule pH monitoring may enhance GERD diagnosis, though it is not widely used in Latin America. This study aimed to categorize patients with borderline AET as GERD or non-GERD using prolonged wireless capsule pH monitoring, assess treatment response, and compare tolerance and interference with 24-hour impedance testing. Thirty-three patients with persistent reflux symptoms and borderline AET (4%-6%) from a 24-hour impedance study were included. Exclusions were prior esophageal surgery, major motility disorders, or unreliable impedance tests. A 96-hour off-proton pump inhibitor (PPI) wireless capsule pH monitoring was performed. Patients were categorized as GERD (AET >6% for 2+ days) or non-GERD (AET <4% for 4 days). Treatment was based on these categories, and GerdQ scores were assessed at baseline and 8 weeks. Three patients were excluded due to incomplete data. Of the 30 patients, 16 (53%) were classified as GERD, 6 (20%) as non-GERD, and 8 (27%) remained borderline. Wireless capsule monitoring provided a diagnosis in 73% of borderline cases. GERD patients responded well to PPI optimization, while non-GERD patients benefited from neuromodulation. Tolerance and daily activity interference were better with wireless capsule monitoring. Prolonged wireless capsule pH monitoring effectively categorized over 70% of borderline AET patients, leading to improved treatment outcomes with good patient tolerance.

KEY POINTS

Twenty-four-hour pH metry alone is inferior to additional impedance monitoring in the diagnosis of gastroesophageal reflux disease, particularly in presence of reduced gastric acid secretion

BACKGROUND

Current gold standard for the diagnosis of gastroesophageal reflux disease (GERD) is 24-hour pH metry though it fails to detect non-acidic reflux. The sensitivity of 24-hour pH metry alone (both catheter-based and Bravo capsule) is questionable, especially if gastric acid secretion is low due to reduced parietal cell mass, Helicobacter pylori-induced gastric atrophy and antisecretory therapy. Accordingly, we analyzed the diagnostic ability of 24-hour pH metry as compared to impedance monitoring in relation to the gastric pH without antisecretory therapy.

METHODS

A retrospective analysis of prospectively collected data from 150 patients with suspected GERD undergoing a 24-hour pH impedance study was done.

RESULTS

Among 150 patients with symptoms suggestive of GERD, 106 (70.6%) had confirmed GERD diagnosed either by 24-hour pH metry alone (10 [9.4%]), impedance monitoring alone (49 [46.2%]) or both (47 [44.3%]). Abnormal reflux of acidic and non-acidic gastric contents was detected by 24-hour pH metry and 24-hour impedance monitoring in 57/106 (53.7%) and 96/106 (90.5%) of patients, respectively (p < .00001). Patients with GERD diagnosed by 24-hour impedance monitoring had a higher mean gastric pH (2.9 [median 1.3, IQR 5.3]) than those diagnosed by 24-hour pH metry (2.1 [median 1.4, IQR 2.6]) or both (1.6 [median 1.2, IQR 2.1]) (p = 0.001).

CONCLUSION

Twenty-four-hour impedance monitoring detects GERD more often than 24-hour pH metry. Patients with higher mean gastric pH leading to non-acidic reflux were more often diagnosed by 24-hour impedance monitoring than 24-hour pH metry. Thus, 24-hour pH metry alone is inferior to additional impedance monitoring in the diagnosis of GERD, particularly in presence of reduced gastric acid secretion.

WIRELESS PH MONITORING AND CONVENTIONAL ESOPHAGEAL PH MONITORING: COMPARATIVE STUDY OF DISCOMFORT, LIMITATIONS IN DAILY ACTIVITIES AND COMPLICATIONS

Background:

The catheter of the esophageal pH monitoring is associated with nasal and throat discomfort, and different behave in patients. The capsule of the wireless pH monitoring may cause chest pain and complications.

Aim:

To compare the wireless and conventional pH monitoring concerning the degree of discomfort and limitations in daily activities, complications, ability to diagnose pathological reflux, and costs.

Methods: Twenty-five patients with symptoms of gastroesophageal reflux were prospectively submitted, in a simultaneous initial period, to 24-hour catheter esophageal pH monitoring and 48-hour wireless system. After removing each system, patients underwent a specific clinical questionnaire.

Results:

Fifteen patients (60%) pointed a higher discomfort in the introduction of the capsule (p=0.327). Discomfort and limitations in daily activities were lower on 2^nd day (p<0.05); however, continued to be expressive (32% to 44%). Chest pain occurred in 13 (52%) patients. The diagnostic gain of pathological reflux was 12% with the wireless system (p=0.355).

Conclusions:

1) There is no significant difference between the discomfort mentioned in the introduction of the capsule and the catheter; 2) during reflux monitoring, the wireless system provides significant less discomfort and limitations in daily activities; 3) there is no significant difference between the two methods in the ability to diagnose pathological reflux; 4) wireless pH monitoring has higher cost.

Esophageal pH Capsule Retention

The wireless pH capsule is widely used to evaluate gastroesophageal reflux disease in patients. Common complications include premature capsule detachment, dysphagia, chest pain, and technical malfunctions. We present a 6-year-old boy who presented to our institution with a 2-day history of coffee-ground emesis. A pH capsule was found to be lodged in his distal esophagus 45 days after initial placement. We explore the possible reasons for capsule retention and briefly discuss the safety implications of this finding because we believe that this complication may be underreported.

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.

Safety and Efficacy of Wireless pH Monitoring in Patients Suspected of Gastroesophageal Reflux Disease: A Systematic Review

INTRODUCTION

The primary aim of this systematic review was to determine the safety, technical efficacy, and effectiveness of 48-hour wireless pH monitoring (WM) for gastroesophageal reflux disease (GERD), compared with no pH monitoring in patients who failed to tolerate a catheter. In the absence of eligible studies, the secondary aim was to determine these performance characteristics for WM relative to catheter-based pH monitoring (CBM) in patients suspected of GERD, who are able to tolerate a catheter.

METHODS

A protocol was registered on the PROSPERO database (CRD42013005852) before conducting the systematic review, which included the study selection criteria, and critical appraisal methods. Several key databases were searched to identify eligible comparative studies.

RESULTS

Chest pain occurred more often with WM compared with CBM; however, other adverse events were reported less frequently with WM. Technical failures, mostly due to attachment failures and early capsule detachments, were 3 times higher with WM, compared with CBM, [pooled relative risk (from meta-analysis)=3.3; 95% confidence interval, 1.63-6.81; I=0%; P=0.012; k=8). The sensitivity and specificity of WM varied widely, depending on type of analysis, monitoring time, capsule placement, reference standard, and diagnostic threshold.

DISCUSSION

WM is usually better tolerated than CBM but has more technical problems. Test accuracy was highly variable between studies; therefore, conclusions could not be drawn regarding the performance of the 2 tests. To make meaningful comparisons between WM and CBM a consensus is needed on the diagnostic threshold for GERD, monitoring time, appropriate capsule positioning, and the reference standard.

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.

An Investigation of Oral Exposure Variability and Formulation Strategy: A Case Study of PI3Kδ Inhibitor and Physiologically Based Pharmacokinetic Modeling in Beagle Dogs

It is well acknowledged that drugs with poor aqueous solubility are often associated with poor oral absorption. Fortunately, drugs with a basic pKa can take advantage of solubilization in the stomach under the acidic environment to improve exposure. Consequently, high in vivo variability is often observed when stomach pH is altered. When issue encountered, enabling formulations are often used to solve the problem. However, each enabling formulation has its limitations and the situation can be further complicated by other absorption distribution metabolism elimination parameters. Therefore, formulation strategies need to consider various scenarios in order to be effective. Compound 1 is a potent phosphoinositide 3-kinase delta inhibitor with poor intrinsic solubility and 2 basic pKas. It was dosed as a suspension in dogs and found to have mediocre oral bioavailability with high variability. It was hypothesized that this variability was caused by their stomach pH variability. Pharmacokinetic modeling suggested that the issue could be improved with particle size reduction. Meanwhile, it was found that although the Madin-Darby canine kidney permeability was reasonable, Madin-Darby canine kidney transfected with human MDR1 gene (MDCK-MDR1) suggested that Compound 1 is an efflux transporter substrate. Findings were integrated into the design for in vivo studies in dogs. Data obtained from those studies allowed us to quickly narrow down the formulation approaches.

Wireless esophageal pH capsule for patients with gastroesophageal reflux disease: A multicenter clinical study

AIM: To investigate the feasibility and safety of pH capsule to monitor pH in patients with gastroesophageal reflux disease (GERD).

METHODS: Ninety-one patients with symptoms suggestive of GERD were enrolled in this study, 46 of whom were randomized to the pH capsule group; the remaining 45 patients used the conventional catheter and pH capsule simultaneously. The pH data and traces were recorded via automatic analysis, and capsule detachment was assessed using X-ray images. All of the patients were required to complete a questionnaire regarding tolerance with the capsule.

RESULTS: The capsules were successfully attached on the first attempt, and no early detachment of the capsules was observed. Compared to the 24-h pH data recorded with the conventional catheter, the data collected with the pH capsule showed no significant differences in 24-h esophageal acid exposure. The measurements of esophageal acid exposure over 24 h collected with the two devices showed a significant correlation (r² = 0.996, P < 0.001). Capsule detachment occurred spontaneously in 89 patients, and 2 capsules required endoscopic removal due to chest pain. The capsule was associated with less interference with daily activity.

CONCLUSION: The wireless pH capsule provides a feasible and safe method for monitoring gastroesophageal reflux and therefore may serve as an important tool for diagnosing GERD.

Wireless oesophageal pH monitoring: establishing values in a multiracial cohort of asymptomatic Asian subjects

BACKGROUND

Wireless oesophageal (Bravo) readings in healthy European and American subjects show varied results. Values in Asians remain unstudied.

AIMS

We performed Bravo studies in healthy Asians to determine if values differed from previously published and identified reflux parameters to differentiate healthy volunteers from patients.

METHODS

Fifty healthy volunteers were recruited between August 2009 and August 2011 to undergo 48 h wireless pH monitoring. Bravo capsule was introduced transorally and placed 6 cm above the squamocolumnar junction. Acid reflux parameters were compared against 41 patients previously evaluated for non-erosive reflux disease.

RESULTS

Five volunteers were excluded. Capsule dislodgement occurred in four and three volunteers on study days 1 and 2 respectively. Forty and 37 volunteers (73% male, mean age 33.0 ± 7.6 years) had interpretable readings at 24 and 48 h, respectively. Percentage of time oesophageal pH<4 in 37 volunteers who completed 48 h recordings was 1.6% (7.5%), 1.5% (6.3%) and 1.9% (5.8%) on days 1, 2 and overall study duration, respectively.

CONCLUSION

Bravo readings in Asians differed from previously published. Percentage of time oesophageal pH<4 on day 2 and DeMeester score on day 2 (95th percentile 22.9) best discriminated healthy volunteers from patients.

Comparative study of two modes of gastroesophageal reflux measuring: conventional esophageal pH monitoring and wireless pH monitoring

CONTEXT

Esophageal pH monitoring is considered to be the gold standard for the diagnosis of gastroesophageal acid reflux. However, this method is very troublesome and considerably limits the patient's routine activities. Wireless pH monitoring was developed to avoid these restrictions.

OBJECTIVE

To compare the first 24 hours of the conventional and wireless pH monitoring, positioned 3 cm above the lower esophageal sphincter, in relation to: the occurrence of relevant technical failures, the ability to detect reflux and the ability to correlate the clinical symptoms to reflux.

METHODS

Twenty-five patients referred for esophageal pH monitoring and with typical symptoms of gastroesophageal reflux disease were studied prospectively, underwent clinical interview, endoscopy, esophageal manometry and were submitted, with a simultaneous initial period, to 24-hour catheter pH monitoring and 48-hour wireless pH monitoring.

RESULTS

Early capsule detachment occurred in one (4%) case and there were no technical failures with the catheter pH monitoring (P = 0.463). Percentages of reflux time (total, upright and supine) were higher with the wireless pH monitoring (P < 0.05). Pathological gastroesophageal reflux occurred in 16 (64%) patients submitted to catheter and in 19 (76%) to the capsule (P = 0.355). The symptom index was positive in 12 (48%) patients with catheter pH monitoring and in 13 (52%) with wireless pH monitoring (P = 0.777).

CONCLUSIONS

1) No significant differences were reported between the two methods of pH monitoring (capsule vs catheter), in regard to relevant technical failures; 2) Wireless pH monitoring detected higher percentages of reflux time than the conventional pH-metry; 3) The two methods of pH monitoring were comparable in diagnosis of pathological gastroesophageal reflux and comparable in correlating the clinical symptoms with the gastroesophageal reflux.

Reflux and sex: what drives testing, what drives treatment?

Gastroesophageal reflux (GER) affects ∼10-20% of American adults. Although symptoms are equally common in men and women, we hypothesized that sex influences diagnostic and therapeutic approaches in patients with GER. PubMed database between 1997 and October 2011 was searched for English language studies describing symptoms, consultative visits, endoscopic findings, use and results of ambulatory pH study, and surgical therapy for GER. Using data from Nationwide Inpatient Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality, we determined the sex distribution for admissions and reflux surgery between 1997 and 2008. Studies on symptoms or consultative visits did not show sex-specific differences. Even though women are less likely to have esophagitis or Barrett's esophagus, endoscopic studies enrolled as many women as men, and women were more likely to undergo ambulatory pH studies with a female predominance in studies from the US. Surgical GER treatment is more commonly performed in men. However, studies from the US showed an equal sex distribution, with Nationwide Inpatient Sample data demonstrating an increase in women who accounted for 63% of the annual fundoplications in 2008. Despite less common or severe mucosal disease, women are more likely to undergo invasive diagnostic testing. In the US, women are also more likely to undergo antireflux surgery. These results suggest that healthcare-seeking behavior and socioeconomic factors rather than the biology of disease influence the clinical approaches to reflux disease.

24 Versus 48-hour bravo pH monitoring

BACKGROUND

Historical ambulatory pH monitoring systems for the evaluation of gastroesophageal reflux disease have been catheter based and uncomfortable for patients, commonly limiting both their diet and activities. Catheter-based studies have also been reported to underestimate the amount of reflux a patient may have in a normal, routine day. Compared with conventional catheter-based pH monitoring systems, wireless (Bravo) pH monitoring is better tolerated by patients and allows for an increased duration of pH recording. Currently, there is lack of data regarding the optimal duration of wireless studies and concern that day 1 results are not typical of a patient's routine lifestyle, given the effects of sedation. Few studies have evaluated the merits of 24 versus 48-hour wireless pH monitoring.

AIMS

The aims of this study were (1) to identify differences in reflux parameters between 24 versus 48-hour testing as measured by wireless pH monitoring and (2) to assess the effect of 48-hour studies on the number of reflux episodes and symptom correlation as compared with 24-hour studies.

METHODS

A retrospective chart review of 124 consecutive patients who underwent 48-hour wireless esophageal pH monitoring studies was prepared. All patients underwent esophagogastroduodenoscopy using intravenous conscious sedation before wireless capsule placement. Acid reflux variables (including total reflux time, number of reflux episodes, and total percent time of pH<4) and symptom-association probability (SAP) scores were compared for day 1 versus day 2 versus total.

RESULTS

Forty-eight-hour SAP scores were significantly higher when compared with the first 24 hours for all reported primary symptoms. SAP scores were calculated at 24 and 48 hours, respectively for heartburn (56 vs. 65, P<0.0001), regurgitation (65 vs. 80, P<0.0001), chest pain (59 vs. 78, P=0.0009), and cough (55 vs. 64, P=0.0027). In addition, the percentage of SAP scores >95 was significantly higher for both heartburn and regurgitation (34% vs. 48%, P=0.003 and 38% vs. 62%, P=0.005). As expected, 48-hour testing also captured a significantly higher number of reflux episodes as compared with day 1 results alone (97 vs. 47, P<0.0001). There were no statistical differences noted between the 2 days for total percent time of pH <4.

CONCLUSIONS

Forty-eight-hour wireless (Bravo) pH monitoring strengthens symptom correlation as compared with 24-hour results alone and yields a greater percentage of SAP scores >95 for typical symptoms of gastroesophageal reflux disease. Prolonged recording of patient symptoms and/or sedation effects may account for the better symptom correlation. Although there were no statistical differences seen in this study between 24 and 48-hour studies for total percent time pH <4, 48-hour studies captured significantly more reflux episodes as compared with 24 hours of monitoring alone. These results suggest that patients undergoing wireless pH monitoring should have 48-hour studies performed as a standard of practice.

Prolonged, wireless pH-studies have a high diagnostic yield in patients with reflux symptoms and negative 24-h catheter-based pH-studies

BACKGROUND

Catheter-based esophageal pH-monitoring is used to evaluate patients with suspected gastro-esophageal reflux disease (GERD); however false-negative results may occur due to poor tolerance of the catheter with reduced oral intake and activity, or high day-to-day variation in reflux and symptom events. We assessed diagnostic yield and clinical impact of prolonged, wireless pH-monitoring in patients with negative results from 24-h catheter-based studies and ongoing symptoms.

METHODS

Esophageal acid exposure (percentage time pH <4), Symptom Index, and Symptom Association Probability (SAP) were calculated. Diagnostic yield was assessed using Average (mean) and Worst Day (24-h period with highest acid exposure or symptom load) analyses. Outcome data were assessed 6-36 months (median 24) after initiation of definitive therapy based on physiologic testing.

KEY RESULTS

Data from prolonged pH-monitoring up to 96-h (median 72-h) were available from 38 patients. Using Average and Worst Day analysis, esophageal acid exposure was pathologic in 37% and 47%, whereas SAP was positive in 34% and 63% of patients, respectively. Overall using Average and Worst Day analyses, 61% and 76% patients were diagnosed with GERD based on either pathologic acid exposure or positive symptom association. Of 12 patients that underwent antireflux surgery, 10(83%) reported a good outcome at a median 24 months follow-up.

CONCLUSIONS & INFERENCES

Prolonged, wireless pH-monitoring increases test sensitivity and diagnostic yield in patients with continuing esophageal symptoms despite negative 24-h catheter-based pH-studies. Without a definitive diagnosis, many would not have received effective treatment.

Technical problems produced by the Bravo pH test in nonerosive reflux disease patients

AIM: To evaluate the technical failures of the Bravo pH test in a population with nonerosive gastroesophageal reflux disease.

METHODS: Over the course of a year, we prospectively studied a population of 66 nonerosive reflux disease patients who received a Bravo pH test. The number and frequency of all technical failures were documented, quantified and analyzed.

RESULTS: A total of 66 patients, with a mean age of 41.7 years, were studied. Technical failures occurred in 15.15% of the sample. The most frequent failures were due to poor data reception (4.5%), early dislodgement (4.5%) and capsule removal (6.1%).

CONCLUSION: The Bravo capsule pH test involves a low but non-negligible rate of technical problems, a fact that must always be considered by physicians.

Guidelines for the diagnosis and management of gastroesophageal reflux disease: an evidence-based consensus

Gastroesophageal reflux disease (GERD) is one of the most common disorders in medical practice. A number of guidelines and recommendations for the diagnosis and management of GERD have been published in different countries, but a Brazilian accepted directive by the standards of evidence-based medicine is still lacking. As such, the aim of the Brazilian GERD Consensus Group was to develop guidelines for the diagnosis and management of GERD, strictly using evidence-based medicine methodology that could be clinically used by primary care physicians and specialists and would encompass the needs of physicians, investigators, insurance and regulatory bodies. A total of 30 questions were proposed. Systematic literature reviews, which defined inclusion and/or exclusion criteria, were conducted to identify and grade the available evidence to support each statement. A total of 11,069 papers on GERD were selected, of which 6,474 addressed the diagnosis and 4,595, therapeutics. Regarding diagnosis, 51 met the requirements for the analysis of evidence-based medicine: 19 of them were classified as grade A and 32 as grade B. As for therapeutics, 158 met the evidence-based medicine criteria; 89 were classified as grade A and 69 as grade B. In the topic Diagnosis, answers supported by publications grade A and B were accepted. In the topic Treatment only publications grade A were accepted: answers supported by publications grade B were submitted to the voting by the Consensus Group. The present publication presents the most representative studies that responded to the proposed questions, followed by pertinent comments. Follow examples. In patients with atypical manifestations, the conventional esophageal pH-metry contributes little to the diagnosis of GERD. The sensitivity, however, increases with the use of double-channel pH-metry. In patients with atypical manifestations, the impedance-pHmetry substantially contributes to the diagnosis of GERD. The examination, however, is costly and scarcely available in our country. The evaluation of the histological signs of esophagitis increases the diagnostic probability of GERD; hence, the observation of the dimensions of the intercellular space of the esophageal mucosa increases the probability of diagnostic certainty and also allows the analysis of the therapeutic response. There is no difference in the clinical response to the treatment with PPI in two separate daily doses when compared to a single daily dose. In the long term (>1 year), the eradication of H. pylori in patients with GERD does not decrease the presence of symptoms or the high recurrence rates of the disease, although it decreases the histological signs of gastric inflammation. It seems very likely that there is no association between the eradication of the H. pylori and the manifestations of GERD. The presence of a hiatal hernia requires larger doses of proton-pump inhibitor for the clinical treatment. The presence of permanent migration from the esophagogastric junction and the hernia dimensions (>2 cm) are factors of worse prognosis in GERD. In this case, hiatal hernias associated to GERD, especially the fixed ones and larger than 2 cm, must be considered for surgical treatment. The outcomes of the laparoscopic fundoplication are adequate.

To Bravo or not? A comparison of wireless esophageal pH monitoring and conventional pH catheter to evaluate non-erosive gastroesophageal reflux disease in a multiracial Asian cohort

OBJECTIVE

Non-erosive reflux disease (NERD) constitutes the majority of patients with gastroesophageal reflux disease (GERD). Esophageal pH monitoring is useful in distinguishing patients with NERD from functional heartburn. The gastroenterologist often faces the dilemma of choosing the most appropriate investigative modality. The wireless Bravo capsule allows prolonged 48 hour monitoring with improved patient tolerance, but concerns regarding its reduced sensitivity compared to conventional pH catheter have been raised. We compared the prevalence of high esophageal acid exposure and positive symptom correlation profiles (using the symptom index [SI] and symptom association probability [SAP]) in patients who underwent Bravo compared to patients who underwent conventional pH catheter, and evaluated the efficacy of Bravo monitoring in a multiracial Asian cohort.

METHODS

Retrospective analysis of all pH studies performed between January 2004 and February 2009 for patients with persistent reflux symptoms and a normal gastroscopy.

RESULTS

66 (27 Male, 42.4 +/- 13.4 years) and 55 (24 Male, 47.1 +/- 13.3 years) patients underwent wireless and pH catheter evaluation respectively. "True NERD" (abnormal acid exposure) was diagnosed in 26 (39.4%) and 20 (36.4%) patients (pNS) while "acid-sensitive esophagus" (SI > or = 50% and/or SAP > or = 95%) occurred in 14 (21.2%) and 12 (21.8%) patients (pNS) using the wireless and pH catheter respectively. Extended recording time with Bravo led to an incremental diagnostic yield of 30%.

CONCLUSION

The wireless capsule was well tolerated. The diagnostic yield was similar using both modalities. With the increasing availability of impedance-pH technology, it is uncertain if devices that detect only acid-reflux events will be surpassed.

Patient acceptance and clinical impact of Bravo monitoring in patients with previous failed catheter-based studies

BACKGROUND

Standard pH monitoring is performed over 24 h with a naso-oesophageal catheter (C-pH). Limitations include naso-pharyngeal discomfort, nausea and social embarrassment resulting in reduced reflux-provoking activities. Recently a catheter-free pH-monitoring technique has become available. The tolerability and diagnostic yield of this system in patients who failed standard monitoring remain unknown.

AIM

To examine the tolerability and diagnostic outcome of catheter-free pH-monitoring technique in patients who failed standard monitoring.

METHODS

Patients referred for C-pH and catheter-free pH monitoring completed a tolerability questionnaire. Acid exposure in the distal oesophagus and symptom index (SI) were reviewed.

RESULTS

Over 4 years, 883/1751 (50%) of patients with typical reflux symptoms referred for C-pH were diagnosed with gastro-oesophageal reflux disease (GERD) based on a pathological percentage time acid exposure (%time pH <4);134 (8%) patients failed C-pH and, of these, 129 successfully completed 2-day catheter-free pH monitoring. Ninety-eight (76%) of these patients had a pathological percentage pH <4 on either day compared with 49/102 (49%) of contemporaneous C-pH patients (P < 0.01). There was no difference in SI for heartburn (35% vs. 42%; P = 0.49). The questionnaire demonstrated a preference for catheter-free pH monitoring (96%) with less restriction in activities of daily living, naso-pharyngeal discomfort, dysphagia and chest pain.

CONCLUSIONS

Tolerance and satisfaction with catheter-free pH monitoring are high in patients who had previously failed C-pH; catheter-free pH monitoring assists the definitive diagnosis of GERD in this group.

A novel placement method of the Bravo wireless pH monitoring capsule for measuring intragastric pH

PURPOSE

The delivery system of the Bravo capsule was designed for placement on the esophagus. We evaluated the feasibility of our novel placement method of the Bravo capsule using a clip to monitor intragastric pH and to compare the accuracy of the Bravo wireless system to the traditionally used Slimline catheter-Mark III Digitrapper pH monitoring system.

METHODS

The Bravo capsule was placed by clip or conventional delivery system using suction on the gastric wall in 20 fasted subjects. A separate group of ten healthy volunteers underwent simultaneous intragastric pH monitoring for comparison of the two systems with meals.

RESULTS

Early dislodgment rate of the capsules was lower when placed using clipping (20%) than using conventional delivery system (70%) within 48 h after placement. We observed prominent movement of one catheter in the stomach during the study. Post-test calibration drifts of the catheters at pH 7.01 were significantly greater than those of the Bravo capsules (P = 0.02).

CONCLUSION

Our novel clipping method of the Bravo pH capsule placement provided accurate monitoring of intragastric pH with merits of tolerability, acid stability, and fixing position.

The Bravo pH capsule system

Limitations of existing pH recording methodology have been the impetus for the emergence of new technologies focused on improving ambulatory pH monitoring. The Bravo pH capsule system (Bravo, Medtronic, Shoreview, MN) is one of the recent advances that utilize a wireless system to improve patient compliance and extend the period of monitoring. These changes could potentially improve diagnostic accuracy along with patient acceptance. Given this fact, the following review will evaluate the potential benefits that wireless pH monitoring may have over conventional catheter based pH monitoring based on the available data. In addition, we will also focus on the technical aspects related to its safety, tolerability and diagnostic accuracy.

New method for long-term monitoring of intragastric pH

AIM: Consecutive monitoring of intragastric pH using the Bravo^® capsule.

METHODS: We put threads through a Bravo^® capsule and then affixed it to the gastric wall by endoscopic hemoclipping in seven subjects. Study data were uploaded to a computer via Datalink every 48 h. In this way, repeated monitoring of intragastric pH was undertaken.

RESULTS: All subjects were able to monitor gastric pH over a 1-wk period, and five for > 2 wk. No complications were encountered during the monitoring. After pH monitoring, we safely retrieved the capsule endoscopically.

CONCLUSION: Clipping a Bravo^® capsule onto the gastric wall enabled long-term intragastric pH monitoring. This is a methodological report of pH monitoring over a period of > 2 wk.

Gastric pH and gastric residence time in fasted and fed conscious cynomolgus monkeys using the Bravo pH system

PURPOSE

To measure fasted and fed gastric pH and gastric residence time (GRT) in Cynomolgus monkeys using Bravo radiotelemetry capsules.

METHODS

Continuous pH measurements were recorded with Bravo capsules, which were either attached to the monkeys' stomach or administered as free capsules. Meals (either slurry or standard), were administered at designated times with monkeys chair-restrained during slurry meal ingestion.

RESULTS

From the attached capsule studies, the fasted gastric pH (~1.9-2.2) was consistent among monkeys. Under fasted conditions, pH spikes were infrequently observed (once every 7.9 min to 3.6 h) with peaks reaching pH 9.4 and having short durations (<1 min). After feeding, the gastric pH rose quickly and remained alkaline for approximately 4.5-7.5 h before returning to baseline. Although significantly different (p < 0.05), there was overlap between the fasted (153 +/- 87 min) and fed (436 +/- 265 (slurry) and 697 +/- 193 (standard) min) GRT due to considerable inter- and intra-subject variability.

CONCLUSIONS

Fasted gastric pH was similar between monkeys and literature human values. After a meal, the monkey gastric pH was elevated for a longer duration than that in human. The monkey GRT appears longer than that observed in human under both fasted and fed conditions, although this is likely dependent on the Bravo capsule size.