Esophageal Baseline Impedance From High-resolution Impedance Manometry Correlates With Mean Nocturnal Baseline Impedance From pH-impedance Monitoring

Utility of the Post-Reflux Swallow-Induced Peristaltic Wave Index and Mean Nocturnal Baseline Impedance for the Diagnosis of Gastroesophageal Reflux Disease Phenotypes in Children

(1) Objectives: Assessment of novel impedance parameters such as the post-reflux swallow-induced peristaltic wave (PSPW) index and mean nocturnal baseline impedance (MNBI) have been proposed to enhance the accuracy of gastroesophageal reflux disease (GERD) diagnosis. We aimed to evaluate the clinical value of MNBI and the PSPW index in discerning different phenotypes of GERD in children. (2) Methods: We conducted a prospective, observational study that included 49 children aged 5-18 years, referred for MII-pH monitoring due to negative endoscopy and persisting gastroesophageal reflux symptoms despite acid-suppressant treatment. The PSPW index and MNBI were assessed along with conventional metrics. (3) Results: Using a receiver operating characteristic (ROC) curve analysis, MNBI (AUC 0.864) and the PSPW index (AUC 0.83) had very good performance in differentiating between non-erosive reflux disease (NERD) and functional phenotypes. The PSPW index (AUC 0.87) discriminated better between functional heartburn (FH) and reflux hypersensitivity (RH) compared to the MNBI (AUC 0.712). A PSPW cut-off value of 65% provided a sensitivity of 76.9% and a specificity of 90% in distinguishing FH and RH. The PSPW index (AUC 0.87) proved to have better performance than the MNBI (AUC 0.802) in differentiating between FH and non-FH patients. MNBI diagnosed FH with a sensitivity of 84% and a specificity of 80.6% at a cut-off value of 2563 Ω. (4) Conclusions: The PSPW index and MNBI are useful to distinguish between GERD phenotypes in pediatric patients.

The Utility of Novel pH-Impedance Monitoring Parameters (PSPW Index and MNBI) in Pediatric Gastroesophageal Reflux Disease Phenotypes-A Systematic Review

Background/Objectives: Researchers have proposed two novel impedance-pH parameters, mean nocturnal baseline impedance (MNBI) and the post-reflux swallow-induced peristaltic wave (PSPW) index, to enhance the diagnosis of gastroesophageal reflux disease (GERD) and enable better predictions of the effectiveness of anti-reflux therapies. This systematic review aims to synthesize the available evidence on the utility of the PSPW index and MNBI as diagnostic tools for pediatric GERD. Methods: A systematic search of studies reporting PSPW index and MNBI values in patients with GERD was performed in PubMed, Embase, Clarivate, Scopus, Cochrane and Google Scholar databases from their beginning until April 2024. The following terms were used: GERD, children, pediatric, PSPW and MNBI. Results: Eight studies were included, describing 479 patients ranging from 2 months to 17 years old over an 8-year period in 12 pediatric centers. Four studies demonstrated that children with pathological acid exposure have a significantly lower MNBI, with a good discriminatory ability to diagnose GERD. The PSPW index showed lower values in patients with reflux hypersensitivity (RH) compared to those with functional heartburn (FH). Conclusions: Patients with pathological acid exposure tend to exhibit lower MNBI and PSPW index values compared to those with normal acid exposure. MNBI and the PSPW index show promise as diagnostic tools in distinguishing between different GERD phenotypes. Further research is needed to establish standardized diagnostic criteria and optimize the clinical applicability in GERD diagnosis and management.

Novel Diagnostic Techniques in the Evaluation of Gastroesophageal Reflux Disease (GERD)

In our present clinical paradigm, patient symptoms and presentation in the setting of traditional findings from endoscopy (erosive esophagitis, Barrett's esophagus, reflux-mediated stenosis), esophageal high-resolution manometry, and/or ambulatory reflux monitoring (distal esophageal acid exposure time, numbers of reflux events, reflux-symptom association) guide the care of patients with suspected GERD. However, novel metrics and techniques acquired from or performed at endoscopy, manometry, or pH-impedance monitoring, beyond conventional evaluation, are of great interest to the gastroenterology community given the frequent (and sometimes challenging) presentation of suspected GERD. These novel and evolving diagnostic approaches have the potential to enhance the evaluation of these patients and optimize their management. In this invited review, we discuss the present evidence and potential clinical utility of selected GERD metrics and techniques of interest at endoscopy (dilated intercellular spaces, mucosal impedance), manometry (contractile integral, impedance analysis, straight leg raise, multiple rapid swallow maneuvers), and reflux monitoring (mean nocturnal baseline impedance, post-reflux swallow-induced peristaltic wave indices), and how these tools may be most optimally adopted and utilized for clinical care (Fig. 1).

Diagnosis and Management of Refractory Gastroesophageal Reflux Disease

In up to half of patients with symptoms suspected to stem from gastroesophageal reflux disease (GERD), these symptoms persist despite treatment with daily proton pump inhibitor (PPI) therapy. The symptoms may be characterized as typical (eg, heartburn or regurgitation) or atypical (eg, chest pain or cough). These refractory symptoms, which are frequently encountered in clinical practice, may stem from GERD as well as non-GERD etiologies. Among those patients with objective GERD proven on esophagogastroduodenoscopy (EGD) and/ or ambulatory reflux testing, approximately one-fifth may manifest suboptimal symptom response to PPI therapy. After introducing the initial evaluation of patients with suspected GERD symptoms, this article discusses approaches to the esophageal diagnostic workup of patients with refractory symptoms in the setting of proven GERD, focusing on EGD, high-resolution manometry (HRM), and pH-impedance monitoring during treatment with PPI therapy. EGD evaluates for esophagitis, peptic stricture, and hiatal hernia, as well as eosinophilic esophagitis. HRM rules out confounding esophageal motor disorders, identifies behavioral disorders, characterizes the antireflux barrier, and assesses esophageal contractile reserve to help tailor potential antireflux interventions. pH-impedance monitoring during treatment with PPI therapy can help distinguish between PPI-refractory GERD-as evidenced by pathologic acid exposure despite PPI therapy and/or excess burden of reflux events regardless of acidity-and PPI-controlled GERD. This article also discusses potential approaches for patients with symptoms stemming from refractory GERD, encompassing lifestyle, pharmacologic, endoscopic, and surgical management options.

The Clinical Utility of Provocative Maneuvers at Esophageal High-resolution Manometry (HRM)

Esophageal high-resolution manometry (HRM) assesses esophageal motor function and is indicated both for evaluation of esophageal symptoms and before antireflux interventions. HRM studies are interpreted and esophageal motor diagnoses made according to the Chicago Classification, version 3.0 algorithm, which is based on ten 5 mL supine water swallows. However, this practice of single liquid swallows performed in the supine position does not reflect typical "real-life" swallowing, and may not reproduce the patient's presenting symptoms. Therefore, provocative maneuvers at HRM-beyond these 10 standard swallows-can afford additional insights into esophageal motor function with clinically significant implications, and represent areas of exciting investigation and innovation. Accordingly, the 2020 American College of Gastroenterology Guidelines on Esophageal Physiologic Testing conditionally recommend their inclusion in the HRM protocol. In this clinical review, we discuss the supporting data for and clinical utility of provocative maneuvers at HRM that include changes in body position or accessories (upright swallows, "bridge" position, straight leg raise, abdominal compression), bolus consistency (solid swallows, test meals, postprandial high-resolution impedance manometry), bolus frequency (multiple rapid swallows), the volume of bolus (rapid drink challenge/multiple water swallows), and the use of pharmacological agents.

Esophageal contractile segment impedance from high-resolution impedance manometry correlates with mean nocturnal baseline impedance and acid exposure time from 24-hour pH-impedance monitoring

Esophageal baseline impedance (BI) acquired during esophageal contraction (contractile segment impedance [CSI]) is proposed to improve BI accuracy in gastroesophageal reflux disease (GERD). We evaluated associations between CSI and conventional and novel GERD metrics. We analyzed high-resolution impedance manometry (HRIM) and ambulatory pH-impedance studies from 51 patients (58.6 ± 1.5 years; 26% F) with GERD symptoms studied off antisecretory therapy. Patients with achalasia or absent contractility were excluded. CSI (averaged across 10 swallows) and BI-HRIM (from the resting landmark phase) were acquired from the distal impedance sensors (distal sensor and 5 cm above the lower esophageal sphincter). Acid exposure time (AET) and mean nocturnal baseline impedance (MNBI) were calculated. Associations between CSI, BI-HRIM, MNBI, and AET were evaluated using correlation (Pearson) and receiver operating characteristic (ROC) analysis. Presenting symptoms included heartburn (67%), regurgitation (12%), cough (12%), and chest pain (10%). CSI-distal and CSI-5 each correlated with BI-HRIM, AET, and distal MNBI. Associations with AET were numerically stronger for CSI-distal (r = -0.46) and BI-HRIM-distal (r = -0.44) than CSI-5 (r = -0.33), BI-HRIM-5 (r = -0.28), or distal MNBI (r < -0.36). When compared to AET <4%, patients with AET >6% had significantly lower CSI-distal and BI-HRIM-distal values but not CSI-5, BI-HRIM-5, or MNBI. ROC areas under the curve for AET >6% were numerically higher for CSI-distal (0.81) than BI-HRIM-distal (0.77), distal MNBI (0.68-0.75), CSI-5 (0.68), or BI-HRIM-5 (0.68). CSI from HRIM studies inversely correlates with pathologic AET and has potential to augment the evaluation of GERD.