Review article: gastro-oesophageal reflux disease as a functional gastrointestinal disorder

Usefulness of baseline impedance in patients with proton pump inhibitor-refractory nonerosive reflux disease

BACKGROUND AND AIM

Approximately more than half of patients with non-erosive reflux disease (NERD) do not respond to proton pump inhibitor (PPI) therapy. Although NERD is a heterogeneous entity, previous study showed that multichannel intraluminal impedance (MII)-pH monitoring could distinguish reflux-related disease from PPI-refractory NERD. The aim of this study was to examine the usefulness of baseline impedance in PPI-refractory NERD patients.

METHODS

We used MII-pH monitoring to analyze reflux parameters, symptom index (SI), and baseline impedance in 37 PPI-refractory NERD patients on PPI. Reflux was divided into acid (nadir pH ≤ 4) and non-acid (nadir pH > 4). Subjects were classified as having reflux-related disease based on abnormal reflux parameters or positive SI (≥ 50%), or non-reflux-related disease, including functional heartburn, based on negative SI with normal reflux parameters.

RESULTS

A total of 26 of the 37 subjects were diagnosed with reflux-related disease, including eight with acid-reflux type and 18 with non-acid-reflux type, and nine with functional heartburn and two with pseudohypersalivation. There were no significant differences in the clinical characteristics of the acid-reflux type, non-acid-reflux type, and functional heartburn groups. The baseline impedance value in the acid-reflux type (1245 ± 392 Ω) was significantly lower than that in the non-acid-reflux type (2824 ± 1160 Ω) and functional heartburn (3546 ± 1353 Ω) groups. Baseline impedance values inversely correlated with reflux percent time, acid-reflux time, and acid exposure time.

CONCLUSION

Among patients with PPI-refractory NERD, acid-reflux type was associated with lower baseline impedance compared with non-acid-reflux type and functional heartburn.

Effect of monotherapy and combination therapy of pantoprazole and aprepitant in gastric esophageal reflux disease in albino rats

The present study was undertaken to elucidate the effect of pantoprazole and aprepitant on experimental esophagitis in albino rats. Groups of rats, fasted overnight, received normal saline (3 mL/kg, sham control) or toxic control (3 mL/kg) or pantoprazole (30 mg/kg) or aprepitant (10 mg/kg), or their combinations and were subjected to pylorus and forestomach ligation. Animals were sacrificed after 8 h and evaluated for the gastric pH, volume of gastric juices, total acidity, esophagitis index, and free acidity. Esophageal tissues were further subjected to estimations of TBARS, GSH, catalase, and SOD. Treatment with pantoprazole and aprepitant significantly inhibited the gastric secretion, total acidity, and esophagitis index. The treatment also helped to restore the altered levels oxidative stress parameters to normal.

Pathogenesis of proton-pump inhibitor-refractory non-erosive reflux disease according to multichannel intraluminal impedance-pH monitoring

BACKGROUND AND AIM

Proton-pump inhibitor (PPI) therapy is the first-line treatment for gastroesophageal reflux disease; however, there are some reports of PPI failure in cases of non-erosive reflux disease (NERD). Among the pathogenic factors associated with PPI-refractory NERD, reflux other than acid reflux can not be detected by conventional pH monitoring. The purpose of this study was to clarify the usefulness of multichannel intraluminal impedance-pH (MII-pH) monitoring for PPI-refractory NERD patients and examine the pathogenesis.

METHODS

We used MII-pH monitoring to examine 29 PPI-refractory NERD patients on PPI treatment. Reflux parameters, symptom index (SI: positive if ≥ 50%), and proximal migration were analyzed. The acidity of the reflux was divided into acid (nadir pH ≤ 4) and non-acid (nadir pH > 4). Subjects were classified into reflux-related disease (abnormal reflux parameters or positive SI) and non-reflux-related disease (normal reflux parameters and negative SI).

RESULTS

Of the 29 subjects, 21 were diagnosed with reflux-related disease, including 6 with acid reflux type and 15 with non-acid reflux type, and 8 were diagnosed with non-reflux-related disease. Of the total 1816 liquid reflux episodes, 834 showed proximal migration, which was more common in symptomatic reflux than in asymptomatic reflux.

CONCLUSIONS

MII-pH monitoring could distinguish reflux-related disease (especially non-acid type) from PPI-refractory NERD. Proximal migration was associated with symptomatic reflux in PPI-refractory NERD patients.

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.

The role of nonacid reflux in NERD: lessons learned from impedance-pH monitoring in 150 patients off therapy

INTRODUCTION

Nonerosive reflux disease (NERD) is the most common form of gastroesophageal reflux disease. While the role of acid reflux has been established, the relevance of nonacid reflux in generating symptoms in NERD is unknown.

AIM

To evaluate the diagnostic utility of impedance-pH monitoring in NERD patients.

METHODS

Patients with typical reflux symptoms (heartburn and/or regurgitation) and normal endoscopy (NERD) underwent a combined impedance-pH monitoring off proton pump inhibitor (PPI) therapy. Previously investigated 48 healthy volunteers served as controls. Distal esophageal acid exposure (% time pH < 4), number of acid and nonacid reflux episodes, 2-min window symptom index (SI; positive if > or = 50%), and symptom association probability (SAP; positive if > or = 95%) were calculated.

RESULTS

Between June 2004 and June 2007, 150 NERD patients (82 women, mean age 48 yr, range 18-78 yr) reported symptoms during the impedance-pH monitoring. NERD patients had more reflux episodes (median [25th-75th percentile]) compared with healthy volunteers (total: 46 [26-65] vs 32 [18-43], P < 0.05; acid: 29 [14-43] vs 17 [8.5-31.0], P < 0.05; and nonacid: 20 [15-27] vs 18 [13.5-26.0], P = NS). Sixty-three (42%) patients had abnormal % time pH < 4. Among 87 patients with normal % time pH < 4., 22 (15%) had a positive SAP for acid, 19 (12%) for nonacid reflux, and 7 (5%) for both. Classifying patients with symptomatic nonacid reflux as having a hypersensitive esophagus reduced the number of patients with functional heartburn from 65 (43%) to 39 (26%).

CONCLUSION

Monitoring for nonacid reflux in NERD patients reduces the proportion of patients classified as having "functional heartburn." Studies assessing the clinical implications of these findings are warranted.

Stratification and symptom characteristics of non-erosive reflux disease based on acid and duodenogastroesophageal reflux

BACKGROUND AND AIM

The subgroups and symptom characteristics of non-erosive reflux disease (NERD) based on acid and duodenogastroesophageal reflux may be different in Chinese patients to Western patients. This study aimed to explore the stratification and symptom characteristics of patients with NERD.

METHODS

Patients with typical heartburn and/or acid regurgitation symptoms were enrolled. Each patient filled out a questionnaire. An upper gastrointestinal endoscopy was performed for each patient followed by simultaneous ambulatory 24-h esophageal pH and Bilitec (bilirubin) monitoring. A symptom index (SI) of > or =50% was considered to be positive.

RESULTS

Eighty-two consecutive NERD patients were evaluated. Abnormal (NERD pH+) and normal (NERD pH-) 24-h pH tests were found in 24 (29.3%) and 58 (70.7%) patients, respectively. Among 42 NERD pH- patients who reported heartburn symptoms during monitoring, SI was positive in 19 (45.2%) patients (NE-SI+) and negative in 23 (54.8%) patients (NE-SI-). Pathological duodenogastroesophageal reflux (DGER) was found in 43 (52.4%) patients. No significant differences were noted regarding the prevalence of other upper gastrointestinal symptoms, except for acid regurgitation in NERD pH+ and NERD pH- groups. Additionally, no significant differences were seen in the prevalence of other symptoms, except for chest pain, in groups with pathological and normal DGER.

CONCLUSION

The proportion of NERD patients with pathological acid reflux was somewhat lower than that reported in Western countries. The role of DGER in NERD may be important. It is difficult to differentiate whether NERD patients have pathological acid or bile reflux according to symptoms.

Endotherapy and surgery for GERD

Today, there are several modalities to treat gastroesophageal reflux disease (GERD) (medications, endoscopic therapies, surgery) and such therapies can be used either singly, or in tandem, or in combination with the others, aiming at "normalization" of the patient's GERD-related quality of life and, if possible, esophageal acid exposure. Several intermediate end points or clinically significant outcomes have not been reached by some therapeutic modalities and no single modality is or can be perfect. Statistically significant improvements in these intermediate end points have been shown in "some" but not all studies. Although healing of esophagitis can be accomplished with either medical or surgical therapy, there is inadequate data with endotherapies, because most patients treated with endotherapies have had prior trials of proton pump inhibitors (PPIs) and hence healed their esophagitis. Effective prevention of complications, such as esophageal adenocarcinoma, remains challenging for all modalities. Patients who have not normalized their GERD-related quality of life with once or twice daily PPI therapy should undergo functional esophageal evaluation with pH testing and esophageal motility study and they should be evaluated by both an endoscopist and a surgeon. The decision on how to proceed should be made on the basis of the criteria for endotherapy and surgery, availability of local endoscopic and surgical expertise and patients' preference. Such multimodality therapy model is in many ways similar to the long-term management of coronary artery disease where pharmacotherapy, angioplasty, and bypass surgery are frequently used in tandem or in combination. Multimodality therapy aiming at normalization of GERD-related quality of life is an option today, and should be available to all patients in need of therapy. The target population for GERD endotherapy currently consists of PPI-dependent GERD patients, who have a small (<2-cm-long) or no sliding hiatal hernia, and without severe esophagitis or Barrett esophagus. Thus far, only Stretta and the NDO plicator have been studied in sham-controlled trials. Registries of complications suggest that these techniques are relatively safe, but serious morbidity, including rare mortality have been reported (for a continuous update on complications related to endoscopic therapies see: http://www.fda.gov/cdrh/maude.html). All can be performed on an outpatient basis, under intravenous sedation and local pharyngeal anesthesia. Future comparative studies with predetermined clinically significant end points, validated outcome measures, prolonged follow-up, and complete complication registries will eventually determine the precise role of endoscopic procedures for the patients with GERD.

Non-erosive reflux disease, functional heartburn and gastroesophageal reflux disease; insights into pathophysiology and clinical presentation

Non-erosive reflux disease (NERD) has emerged as a real entity in the spectrum of gastroesophageal reflux disease (GERD) and may, indeed, represent the most common manifestation of reflux disease. Recent information indicates NERD can be further subclassified based on the results of pH studies and suggests that functional heartburn needs to be differentiated as that subgroup of patients in which there appears to be no relationship between symptoms, however 'typical' of GERD, and acid exposure. Other aspects of NERD need to be appreciated, including overlap with functional dyspepsia and the potential variations in response to such therapeutic interventions as acid-suppressive therapy and fundoplication. It seems quite possible that our failure to separate functional heartburn from NERD, in general, has contributed, in large measure, to diagnostic difficulties and therapeutic disappointment in GERD. An appreciation of the range of entities, of different etiology and pathology, within NERD will foster the development of effective approaches to the assessment and therapy of this challenging disorder.