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

Novel Advanced Impedance Metrics on Impedance-pH Testing Predict Lung Function Decline in Idiopathic Pulmonary Fibrosis

INTRODUCTION

Gastroesophageal reflux has been associated with idiopathic pulmonary fibrosis (IPF). Mean nocturnal baseline impedance (MNBI) is a marker of esophageal mucosal integrity, whereas postreflux swallow-induced peristaltic wave (PSPW) index reflects esophageal chemical clearance. Both metrics offer novel ways to assess reflux burden on multichannel intraluminal impedance-pH testing (MII-pH), but their role in extraesophageal reflux remains unclear. We aimed to evaluate the relationship between these novel metrics and lung function decline in patients with IPF.

METHODS

Adults with IPF undergoing prelung transplant MII-pH were enrolled. All patients completed pulmonary function testing (PFT) at the time of MII-pH and at the 1-year follow-up. MNBI was calculated by averaging baseline impedance at three 10-minute intervals (1 AM/2 AM/3 AM). PSPW index was the proportion of all reflux episodes, followed by a peristaltic swallow within 30 seconds. Univariate (Student t-test/Pearson correlation) and multivariable (general linear regression) analyses were performed.

RESULTS

One hundred twenty-five subjects (mean age = 61.7 years, 62% men) were included. Forced expiratory volume in one second and forced vital capacity declined more significantly over 12 months in subjects with lower distal MNBI, proximal MNBI, and PSPW index (all P < 0.05). On multivariable analyses adjusting for age, sex, proton pump inhibitor use, and baseline lung function, distal MNBI (β = -10.86, P = 0.024; β = -8.03, P = 0.045), proximal MNBI (β = -13.5, P = 0.0068; β = -9.80, P = 0.025), and PSPW index (β = -18.1, P = 0.010; β = -12.55, P = 0.050) remained predictive of greater forced expiratory volume in one second and forced vital capacity decline.

DISCUSSION

Low distal MNBI, proximal MNBI, and PSPW index independently predicted more severe lung function decline over 1 year in patients with IPF. These impedance metrics may have prognostic value and support a role for reflux in IPF pathogenesis.

Esophageal Nocturnal Baseline Impedance and Post-reflux Swallow-induced Peristaltic Wave Index in Identifying Proton Pump Inhibitor-refractory Non-erosive Reflux Disease

Background/Aims

Esophageal mean nocturnal baseline impedance (MNBI) levels and post-reflux swallow-induced peristaltic wave (PSPW) index could increase the diagnostic value of 24-hour multichannel intraluminal impedance and pH monitoring in patients with gastroesophageal reflux disease. This study aims to compare the MNBI and PSPW index in patients with no evidence of erosive reflux disease.

Methods

Impedance-pH monitoring tracings from 70 patients, 50 with non-erosive reflux disease (NERD) and 20 with functional heartburn (FH), were reviewed. According to proton pump inhibitors (PPI) treatment response, NERD patients were divided into NERD/PPI responders and NERD/PPI nonresponders. MNBI, PSPW index, and intercellular spaces were measured and compared among each group.

Results

MNBI values and PSPW index were lower in NERD patients than in FH (P < 0.01 and P < 0.05, respectively). MNBI positively correlated with PSPW index (r = 0.525, P < 0.001). NERD/PPI responders had lower MNBI values and PSPW index compared to NERD/PPI nonresponders (both P < 0.01). MNBI and PSPW index distinguished NERD from FH patients with an area under the curve of 0.914 and 0.677, respectively. Wider intercellular space could be identified in patients with NERD (P < 0.01).

Conclusion

MNBI and PSPW index may differentiate NERD from FH patients and relate to PPI treatment efficacy in patients with NERD.

Non-acid Reflux: When It Matters and Approach to Management

PURPOSE OF REVIEW

This narrative review focuses on the presentation, contributing factors, diagnosis, and treatment of non-acid reflux. We also propose algorithms for diagnosis and treatment.

RECENT FINDINGS

There is a paucity of recent data regarding non-acid reflux. The recent Porto and Lyon consensus statements do not fully address non-acid reflux or give guidance on classification. However, recent developments in the lung transplantation field, as well as older data in the general population, argue for the importance of non-acid reflux. Extrapolating from the Porto and Lyon consensus, we generally classify pathologic non-acid reflux as impedance events > 80, acid exposure time < 4%, and positive symptom correlation on a standard 24-h pH/impedance test. Other groups not meeting this criteria also deserve consideration depending on the clinical situation. Potential treatments include lifestyle modification, increased acid suppression, alginates, treatment of esophageal hypersensitivity, baclofen, buspirone, prokinetics, and anti-reflux surgery in highly selected individuals. More research is needed to clarify appropriate classification, with subsequent focus on targeted treatments.

The Prevalence of Rome IV Nonerosive Esophageal Phenotypes in Children

OBJECTIVES

To assess the prevalence of Rome IV nonerosive esophageal phenotypes in children using multichannel intraluminal impedance testing and to describe the rates of proton pump inhibitor (PPI) responsiveness and the frequency of microscopic esophagitis in these patients.

STUDY DESIGN

We conducted a retrospective review of all children ≥5 years of age who underwent esophagogastroduodenoscopy and multichannel intraluminal impedance testing off PPI therapy for evaluation of typical gastroesophageal reflux symptoms. Only children with symptoms during the multichannel intraluminal impedance testing were included. Children were categorized into the following nonerosive esophageal phenotypes using Rome IV criteria: nonerosive reflux disease, reflux hypersensitivity, and functional heartburn. Rates of esophagitis and responsiveness to acid suppression therapy were assessed.

RESULTS

Forty-five children were included: 27% were categorized as having nonerosive reflux disease, 29% with reflux hypersensitivity (27% acid and 2% nonacid), and 44% with functional heartburn. Older children reported significantly more heartburn (P < .001) than younger children, whereas younger children were more likely to report nonspecific pain (P = .047). There were no differences between groups in other reflux symptoms, rates of responsiveness to PPIs, or the presence of microscopic esophagitis on biopsy.

CONCLUSIONS

Functional heartburn is the most common Rome IV nonerosive esophageal phenotype in children. Neither microscopic esophagitis nor PPI responsiveness can predict phenotype in pediatric patients.

Tailored therapy guided by multichannel intraluminal impedance pH monitoring for refractory non-erosive reflux disease

A relevant percentage of non-erosive reflux disease (NERD) is refractory to proton pump inhibitors (PPIs) treatment. Multichannel intraluminal impedance pH (MII-pH) monitoring should give useful pathophysiological information about refractoriness. Therefore, our aim was to assess whether this technique could be useful to guide a 'tailored' therapy in refractory NERD. We retrospectively recruited NERD patients undergoing MII-pH monitoring for unsuccessful treatment. All patients had undergone upper endoscopy, and those with erosive esophagitis were excluded. No patient received PPI during MII-pH monitoring. Subjects were subgrouped into three categories: acid reflux, non-acid reflux and functional heartburn. MII-pH-guided therapy was performed for 4 weeks as follows: patients with acid reflux received PPI at double dose, patients with non-acid reflux PPI at full dose plus alginate four times a day and patients with functional heartburn levosulpiride 75 mg per day. A visual analog scale (VAS) ranging from 0 to 100 mm was administered before and after such tailored therapy to evaluate overall symptoms. Responders were defined by VAS improvement of at least 40%. Sixty-nine patients with refractory NERD were selected (female-male ratio 43 : 26, mean age 47.6±15.2 years). Overall effectiveness of tailored therapy was 84% without statistical difference among subgroups (88.5% acid reflux, 92% non-acid reflux, 66.6% functional heartburn; P=0.06). Univariate analysis showed that therapy failure directly correlated with functional heartburn diagnosis (OR=4.60) and suggested a trend toward a negative correlation with smoking and a positive one with nausea. However, at multivariate analysis, these parameters were not significant. Functional heartburn experienced a lower median percent VAS reduction than acid reflux (52.5% versus 66.6%, P<0.01) even if equal to non-acid reflux (66.6%). In conclusion, a tailored approach to refractory NERD, guided by MII-pH monitoring, demonstrated to be effective and should be promising to cure symptom persistence after conventional therapy failure. Nevertheless, standardized guidelines are advisable.

Role of altered esophageal intraluminal baseline impedance levels in patients with gatroesophageal reflux disease refractory to proton pump inhibitors

Numerous studies have investigated utility of esophageal intraluminal baseline impedance levels (BILs) in gastroesophageal reflux disease (GERD). However, effect of BILs in refractory GERD (RGERD) has not been well investigated. The aim of this study is to evaluate role of BILs in RGERD patients. Total 62 subjects with refractory gastroesophageal reflux symptoms underwent 24-hour impedance-pH monitoring and gastroendoscopy. Distal BILs in acid reflux type were significantly lower than those in nonacid reflux type and functional heartburn (FH) group. Distal BILs of reflux esophagitis (RE) patients were lower than those of nonerosive reflux disease (NERD) patients, while there were no statistical significance between 2 groups. Patients with severe esophagitis had lower distal BILs than those with mild esophagitis and NERD patients, and patients with severe esophagitis in acid reflux type had the lowest distal BILs. Distal BILs were significantly negatively correlated with DeMeester score, episodes of acid reflux, and acid exposure time, but no correlated with episodes of nonacid reflux. Characteristics of BILs in RGERD patients were similar with those in GERD patients, but might be more complicated. Evaluating BILs in RGERD patients could achieve a better understanding of pathophysiology in RGERD.