Episode-level reflux characteristics: How experienced reviewers differentiate true reflux from artifact on pH-impedance studies

Manual censoring of impedance tracings by the Wingate consensus reduces the number of impedance episodes, impacting on reflux categorization

BACKGROUND

The Lyon consensus classifies the evidence of gastroesophageal reflux (GERD) based on endoscopic features and results of pH/impedance monitoring (pH-MII) including the post-reflux swallow-induced peristaltic wave index (PSPWI) and mean nocturnal baseline impedance (MNBI). The Wingate consensus established criteria to reduce inter-reviewer variability when assessing reflux episodes and PSPWI by impedance. This study aims to assess the influence of the Wingate criteria on the different pH-MII parameters obtained by automated analysis.

METHODS

Thirty consecutive pH-MII off PPI were reviewed according to Wingate criteria. Number of impedance episodes and PSPWI were compared before and after censoring from automatic analysis. Reflux categorization according to Lyon consensus between censored and uncensored data was compared. Pearson correlations between impedance parameters and censored episodes were calculated.

KEY RESULTS

Censoring the tracings significantly reduced the number of reflux episodes (66 [42-90.25] vs. 44.5 [21.5-61.5], p = 0.0105). Reasons for censoring were as follows: 1/ anterograde episode: 9.5 [6-13], 2/ impedance drop <50%: 1 [0-3], 3/ duration <4 s: 1 [0-2], 4/ <2 distal channels: 2.5 [1-4], and 5/ artifacts: 2 [1-5]. Censored episodes were in majority non-acid (16.5 [13-26.5] vs. 2 [0-4], p < 0.00001). Censoring altered the categorization of impedance episodes (<40 episodes, 6 vs. 13 for resp. uncensored vs. censored tracings, 40-80 episodes: 13 vs. 13, and >80 episodes: 11 vs. 4, p = 0.0264), but not the symptom index, the symptom association probability, or the categorization according to the Lyon consensus. Nevertheless, individual tracings were affected. The percentage of censored episodes was inversely correlated with the number of acidic impedance episodes (r = -0.62, p = 0.0002).

CONCLUSION AND INFERENCES

Manual interpretation of impedance tracings based on the Wingate consensus reduces the number of impedance episodes, impacting on reflux categorization. Acidic reflux episodes are less likely to be censored, harboring a potential at improving automatic pH-MII analysis.

Encouraging appropriate use of proton pump inhibitors: existing initiatives and proposals for the future

INTRODUCTION

Proton pump inhibitors (PPIs) have revolutionized the management of acid-related disorders, representing today the mainstay treatment of these conditions. However, despite their large range of indications and usefulness, the remarkable expansion of their use in the last two decades cannot be explained by the increasing prevalence of acid-related diseases only. An inappropriate prescription for clinical conditions in which the pathogenetic role of acid has not been documented has been described, with the natural consequence of increasing the costs and the potential risk of iatrogenic harm due to adverse events and complications recently emerged.

AREAS COVERED

In this review, we summarize current indications of PPIs administration, potential adverse events associated with their chronic utilization, and misuse of PPIs. Moreover, we describe existing and possible initiatives for improving the use of PPIs, and some proposals for the future.

EXPERT OPINION

PPI deprescribing is the preferred and most effective approach to reduce the use of PPIs, rather than adopting sharp discontinuation, probably due to fewer withdrawal symptoms. Nonetheless, large knowledge gaps still exist in clinical practice regarding the optimal approach of PPI deprescribing in various clinical scenarios. Further prospective well-designed international studies are eagerly warranted to improve our perspectives on controlling global PPI inappropriate use.

Application of Artificial Intelligence in Measuring Novel pH-Impedance Metrics for Optimal Diagnosis of GERD

Novel metrics extracted from pH-impedance monitoring can augment the diagnosis of gastroesophageal reflux disease (GERD). Artificial intelligence (AI) is being widely used to improve the diagnostic capabilities of various diseases. In this review, we update the current literature regarding applications of artificial intelligence in measuring novel pH-impedance metrics. AI demonstrates high performance in the measurement of impedance metrics, including numbers of reflux episodes and post-reflux swallow-induced peristaltic wave index and, furthermore, extracts baseline impedance from the entire pH-impedance study. AI is expected to play a reliable role in facilitating measuring novel impedance metrics in patients with GERD in the near future.

Artificial intelligence facilitates measuring reflux episodes and postreflux swallow-induced peristaltic wave index from impedance-pH studies in patients with reflux disease

BACKGROUND/AIM

Reflux episodes and postreflux swallow-induced peristaltic wave (PSPW) index are useful impedance parameters that can augment the diagnosis of gastroesophageal reflux disease (GERD). However, manual analysis of pH-impedance tracings is time consuming, resulting in limited use of these novel impedance metrics. This study aims to evaluate whether a supervised learning artificial intelligence (AI) model is useful to identify reflux episodes and PSPW index.

METHODS

Consecutive patients underwent 24-h impedance-pH monitoring were enrolled for analysis. Multiple AI and machine learning with a deep residual net model for image recognition were explored based on manual interpretation of reflux episodes and PSPW according to criteria from the Wingate Consensus. Intraclass correlation coefficients (ICCs) were used to measure the strength of inter-rater agreement of data between manual and AI interpretations.

RESULTS

We analyzed 106 eligible patients with 7939 impedance events, of whom 38 patients with pathological acid exposure time (AET) and 68 patients with physiological AET. On the manual interpretation, patients with pathological AET had more reflux episodes and lower PSPW index than those with physiological AET. Overall accuracy of AI identification for reflux episodes and PSPW achieved 87% and 82%, respectively. Inter-rater agreements between AI and manual interpretations achieved excellent for individual numbers of reflux episodes and PSPW index (ICC = 0.965 and ICC = 0.921).

CONCLUSIONS

AI has the potential to accurately and efficiently measure impedance metrics including reflux episodes and PSPW index. AI can be a reliable adjunct for measuring novel impedance metrics for GERD in the near future.

Validation of Pharyngeal Acid Reflux Episodes Using Hypopharyngeal Multichannel Intraluminal Impedance-pH

Background/Aims

Hypopharyngeal multichannel intraluminal impedance-pH (HMII-pH) technology incorporating 2 trans-upper esophageal sphincter impedance channels has been developed to detect pharyngeal reflux. We used the HMII-pH technique to validate the candidate pharyngeal acid reflux (PAR) episodes based on the dual-pH tracings and determined the interobserver reproducibility.

Methods

We conducted a cross-sectional study in tertiary centers in Taiwan. Ninety patients with suspected laryngopharyngeal reflux and 28 healthy volunteers underwent HMII-pH test when off acid suppressants. Candidate PAR episodes were characterized by pharyngeal pH drops of at least 2 units and reaching a nadir pH of 5 within 30 seconds during esophageal acidification. Two experts manually independently identified candidate PAR episodes based on the dual-pH tracings. By reviewing the HMII-pH tracings, HMII-pH-proven PAR episodes were subsequently confirmed. The consensus reviews of HMII-pH-proven PAR episodes were considered to be the reference standard diagnosis. The interobserver reproducibility was assessed.

Results

A total of 105 candidate PAR episodes were identified. Among them 84 (80.0%; 95% CI, 71.0-87.0%) were HMII-pH-proven PAR episodes (82 in 16 patients and 2 in 1 healthy subject). Patients tended to have more HMII-pH-proven PAR episodes than healthy controls (median and percentile values [25th, 75th, and 95th percentiles]: 0 [0, 0, 3] vs 0 [0, 0, 0], P = 0.067). The concordance rate in diagnosing HMII-pH-proven PAR episodes between 2 independent observers was 92.2%.

Conclusion

Our preliminary data showed that 80.0% (71.0-87.0%) of the proposed candidate PAR episodes were HMII-pH-proven PAR episodes, among which the interobserver reproducibility was good.

Relevance of Excessive Air Swallowing in GERD Patients With Concomitant Functional Dyspepsia and Poor Response to PPI Therapy

GOALS

The present study was aimed at evaluating the possible role of air swallowing in the association between gastroesophageal reflux disease (GERD) symptoms and concomitant functional dyspepsia (FD) and their role in GERD symptom persistence despite proton pump inhibitor (PPI) therapy.

BACKGROUND

It has been shown that individuals with excessive air swallowing experience FD. It has been also demonstrated that a consistent group of GERD patients not responding to PPI therapy swallow more air during mealtime and also have more mixed refluxes.

MATERIALS AND METHODS

Multichannel intraluminal impedance-pH tracings from consecutive patients were retrospectively evaluated. A validated structured questionnaire was used to evaluate GERD and concomitant FD symptoms. All patients were treated, within the previous year, with at least 8 weeks of standard-dose PPI therapy.

RESULTS

A total of 35 patients with conclusive GERD, 35 patients with reflux hypersensitivity, and 35 with functional heartburn were studied. A direct relationship was observed between the number of air swallows and of mixed refluxes (R=0.64). At receiver operating characteristic curve analysis, air swallows and mixed refluxes were significantly associated to the presence of FD and PPI refractoriness. An air swallow cutoff of 107 episodes/24 hours was identified to discriminate patients with and without FD (sensitivity: 87%, specificity: 82.8%). A mixed reflux cutoff of 34 episodes/24 hours was identified to discriminate PPI responders from nonresponders (sensitivity: 84.8%, specificity: 69%). At multivariate analysis, an abnormal number of air swallows and of mixed refluxes were significantly associated to FD and PPI refractoriness.

CONCLUSION

Our study highlights the relevant role of excessive air swallowing in eliciting both dyspepsia and refractoriness of typical GERD symptoms to PPI therapy.

Applying Lyon Consensus criteria in the work-up of patients with proton pump inhibitory-refractory heartburn

BACKGROUND

A hierarchical approach for gastro-oesophageal reflux disease (GERD) diagnosis by impedance-pH monitoring was proposed by the Lyon Consensus, based on acid exposure time (AET) and supportive impedance metrics.

AIMS

To establish the clinical value of Lyon Consensus criteria in the work-up of patients with proton pump inhibitory (PPI)-refractory heartburn.

METHODS

Expert review of off-therapy impedance-pH tracings from unproven GERD patients with PPI-refractory heartburn prospectively evaluated at referral centers. Impedance metrics, namely total reflux episodes, postreflux swallow-induced peristaltic wave index, and mean nocturnal baseline impedance, were assessed. Expert review of on-therapy preoperative impedance-pH tracings from a separate cohort of surgically treated erosive/nonerosive GERD cases.

RESULTS

Off-therapy, normal, inconclusive, and abnormal AET was found in 59%, 17%, and 23% of 317 cases. Supportive evidence of GERD was provided by abnormal impedance metrics in up to 22% and 62% of cases in the normal and inconclusive AET groups, respectively. Adding the cases with inconclusive AET and abnormal impedance metrics to the abnormal AET group, a significant increase in GERD evidence was observed (from 23% to 37% of cases, p < 0.0002). At the on-therapy presurgical evaluation, abnormal/inconclusive AET and supraphysiological values of impedance metrics showed ongoing reflux in 21% and 90% of 96 cases, respectively (p < 0.00001); a relationship between on-therapy ongoing reflux and PPI-refractory heartburn was confirmed by the favorable surgical outcome at 3-year follow-up, 88% of cases being in persistent off-PPI heartburn remission.

CONCLUSIONS

Impedance-pH monitoring, off- and on-therapy, is of high clinical value in the work-up of patients with PPI-refractory heartburn.